text: /*
   * pgbench.c
   *
   * A simple benchmark program for PostgreSQL
   * Originally written by Tatsuo Ishii and enhanced by many contributors.
   *
   * src/bin/pgbench/pgbench.c
   * Copyright (c) 2000-2019, PostgreSQL Global Development Group
   * ALL RIGHTS RESERVED;
   *
   * Permission to use, copy, modify, and distribute this software and its
   * documentation for any purpose, without fee, and without a written agreement
   * is hereby granted, provided that the above copyright notice and this
   * paragraph and the following two paragraphs appear in all copies.
   *
   * IN NO EVENT SHALL THE AUTHOR OR DISTRIBUTORS BE LIABLE TO ANY PARTY FOR
   * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING
   * LOST PROFITS, ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS
   * DOCUMENTATION, EVEN IF THE AUTHOR OR DISTRIBUTORS HAVE BEEN ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   *
   * THE AUTHOR AND DISTRIBUTORS SPECIFICALLY DISCLAIMS ANY WARRANTIES,
   * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
   * AND FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS
   * ON AN "AS IS" BASIS, AND THE AUTHOR AND DISTRIBUTORS HAS NO OBLIGATIONS TO
   * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
   *
   */
  
  #ifdef WIN32
  #define FD_SETSIZE 1024			/* must set before winsock2.h is included */
  #endif
  
  #include "postgres_fe.h"
  #include "common/int.h"
  #include "common/logging.h"
  #include "fe_utils/conditional.h"
  #include "getopt_long.h"
  #include "libpq-fe.h"
  #include "portability/instr_time.h"
  
  #include <ctype.h>
  #include <float.h>
  #include <limits.h>
  #include <math.h>
  #include <signal.h>
  #include <time.h>
  #include <sys/time.h>
  #ifdef HAVE_SYS_RESOURCE_H
  #include <sys/resource.h>		/* for getrlimit */
  #endif
  
  /* For testing, PGBENCH_USE_SELECT can be defined to force use of that code */
  #if defined(HAVE_PPOLL) && !defined(PGBENCH_USE_SELECT)
  #define POLL_USING_PPOLL
  #ifdef HAVE_POLL_H
  #include <poll.h>
  #endif
  #else							/* no ppoll(), so use select() */
  #define POLL_USING_SELECT
  #ifdef HAVE_SYS_SELECT_H
  #include <sys/select.h>
  #endif
  #endif
  
  #ifndef M_PI
  #define M_PI 3.14159265358979323846
  #endif
  
  #include "pgbench.h"
  
  #define ERRCODE_UNDEFINED_TABLE  "42P01"
  
  /*
   * Hashing constants
   */
  #define FNV_PRIME			UINT64CONST(0x100000001b3)
  #define FNV_OFFSET_BASIS	UINT64CONST(0xcbf29ce484222325)
  #define MM2_MUL				UINT64CONST(0xc6a4a7935bd1e995)
  #define MM2_MUL_TIMES_8		UINT64CONST(0x35253c9ade8f4ca8)
  #define MM2_ROT				47
  
  /*
   * Multi-platform socket set implementations
   */
  
  #ifdef POLL_USING_PPOLL
  #define SOCKET_WAIT_METHOD "ppoll"
  
  typedef struct socket_set
  {
  	int			maxfds;			/* allocated length of pollfds[] array */
  	int			curfds;			/* number currently in use */
  	struct pollfd pollfds[FLEXIBLE_ARRAY_MEMBER];
  } socket_set;
  
  #endif							/* POLL_USING_PPOLL */
  
  #ifdef POLL_USING_SELECT
  #define SOCKET_WAIT_METHOD "select"
  
  typedef struct socket_set
  {
  	int			maxfd;			/* largest FD currently set in fds */
  	fd_set		fds;
  } socket_set;
  
  #endif							/* POLL_USING_SELECT */
  
  /*
   * Multi-platform pthread implementations
   */
  
  #ifdef WIN32
  /* Use native win32 threads on Windows */
  typedef struct win32_pthread *pthread_t;
  typedef int pthread_attr_t;
  
  static int	pthread_create(pthread_t *thread, pthread_attr_t *attr, void *(*start_routine) (void *), void *arg);
  static int	pthread_join(pthread_t th, void **thread_return);
  #elif defined(ENABLE_THREAD_SAFETY)
  /* Use platform-dependent pthread capability */
  #include <pthread.h>
  #else
  /* No threads implementation, use none (-j 1) */
  #define pthread_t void *
  #endif
  
  
  /********************************************************************
   * some configurable parameters */
  
  #define DEFAULT_INIT_STEPS "dtgvp"	/* default -I setting */
  
  #define LOG_STEP_SECONDS	5	/* seconds between log messages */
  #define DEFAULT_NXACTS	10		/* default nxacts */
  
  #define MIN_GAUSSIAN_PARAM		2.0 /* minimum parameter for gauss */
  
  #define MIN_ZIPFIAN_PARAM		1.001	/* minimum parameter for zipfian */
  #define MAX_ZIPFIAN_PARAM		1000.0	/* maximum parameter for zipfian */
  
  int			nxacts = 0;			/* number of transactions per client */
  int			duration = 0;		/* duration in seconds */
  int64		end_time = 0;		/* when to stop in micro seconds, under -T */
  
  /*
   * scaling factor. for example, scale = 10 will make 1000000 tuples in
   * pgbench_accounts table.
   */
  int			scale = 1;
  
  /*
   * fillfactor. for example, fillfactor = 90 will use only 90 percent
   * space during inserts and leave 10 percent free.
   */
  int			fillfactor = 100;
  
  /*
   * use unlogged tables?
   */
  bool		unlogged_tables = false;
  
  /*
   * log sampling rate (1.0 = log everything, 0.0 = option not given)
   */
  double		sample_rate = 0.0;
  
  /*
   * When threads are throttled to a given rate limit, this is the target delay
   * to reach that rate in usec.  0 is the default and means no throttling.
   */
  double		throttle_delay = 0;
  
  /*
   * Transactions which take longer than this limit (in usec) are counted as
   * late, and reported as such, although they are completed anyway. When
   * throttling is enabled, execution time slots that are more than this late
   * are skipped altogether, and counted separately.
   */
  int64		latency_limit = 0;
  
  /*
   * tablespace selection
   */
  char	   *tablespace = NULL;
  char	   *index_tablespace = NULL;
  
  /* random seed used to initialize base_random_sequence */
  int64		random_seed = -1;
  
  /*
   * end of configurable parameters
   *********************************************************************/
  
  #define nbranches	1			/* Makes little sense to change this.  Change
  								 * -s instead */
  #define ntellers	10
  #define naccounts	100000
  
  /*
   * The scale factor at/beyond which 32bit integers are incapable of storing
   * 64bit values.
   *
   * Although the actual threshold is 21474, we use 20000 because it is easier to
   * document and remember, and isn't that far away from the real threshold.
   */
  #define SCALE_32BIT_THRESHOLD 20000
  
  bool		use_log;			/* log transaction latencies to a file */
  bool		use_quiet;			/* quiet logging onto stderr */
  int			agg_interval;		/* log aggregates instead of individual
  								 * transactions */
  bool		per_script_stats = false;	/* whether to collect stats per script */
  int			progress = 0;		/* thread progress report every this seconds */
  bool		progress_timestamp = false; /* progress report with Unix time */
  int			nclients = 1;		/* number of clients */
  int			nthreads = 1;		/* number of threads */
  bool		is_connect;			/* establish connection for each transaction */
  bool		report_per_command;	/* report per-command latencies */
  int			main_pid;			/* main process id used in log filename */
  
  char	   *pghost = "";
  char	   *pgport = "";
  char	   *login = NULL;
  char	   *dbName;
  char	   *logfile_prefix = NULL;
  const char *progname;
  
  #define WSEP '@'				/* weight separator */
  
  volatile bool timer_exceeded = false;	/* flag from signal handler */
  
  /*
   * Variable definitions.
   *
   * If a variable only has a string value, "svalue" is that value, and value is
   * "not set".  If the value is known, "value" contains the value (in any
   * variant).
   *
   * In this case "svalue" contains the string equivalent of the value, if we've
   * had occasion to compute that, or NULL if we haven't.
   */
  typedef struct
  {
  	char	   *name;			/* variable's name */
  	char	   *svalue;			/* its value in string form, if known */
  	PgBenchValue value;			/* actual variable's value */
  } Variable;
  
  #define MAX_SCRIPTS		128		/* max number of SQL scripts allowed */
  #define SHELL_COMMAND_SIZE	256 /* maximum size allowed for shell command */
  
  /*
   * Simple data structure to keep stats about something.
   *
   * XXX probably the first value should be kept and used as an offset for
   * better numerical stability...
   */
  typedef struct SimpleStats
  {
  	int64		count;			/* how many values were encountered */
  	double		min;			/* the minimum seen */
  	double		max;			/* the maximum seen */
  	double		sum;			/* sum of values */
  	double		sum2;			/* sum of squared values */
  } SimpleStats;
  
  /*
   * Data structure to hold various statistics: per-thread and per-script stats
   * are maintained and merged together.
   */
  typedef struct StatsData
  {
  	time_t		start_time;		/* interval start time, for aggregates */
  	int64		cnt;			/* number of transactions, including skipped */
  	int64		skipped;		/* number of transactions skipped under --rate
  								 * and --latency-limit */
  	SimpleStats latency;
  	SimpleStats lag;
  } StatsData;
  
  /*
   * Struct to keep random state.
   */
  typedef struct RandomState
  {
  	unsigned short xseed[3];
  } RandomState;
  
  /* Various random sequences are initialized from this one. */
  static RandomState base_random_sequence;
  
  /*
   * Connection state machine states.
   */
  typedef enum
  {
  	/*
  	 * The client must first choose a script to execute.  Once chosen, it can
  	 * either be throttled (state CSTATE_PREPARE_THROTTLE under --rate), start
  	 * right away (state CSTATE_START_TX) or not start at all if the timer was
  	 * exceeded (state CSTATE_FINISHED).
  	 */
  	CSTATE_CHOOSE_SCRIPT,
  
  	/*
  	 * CSTATE_START_TX performs start-of-transaction processing.  Establishes
  	 * a new connection for the transaction in --connect mode, records the
  	 * transaction start time, and proceed to the first command.
  	 *
  	 * Note: once a script is started, it will either error or run till its
  	 * end, where it may be interrupted. It is not interrupted while running,
  	 * so pgbench --time is to be understood as tx are allowed to start in
  	 * that time, and will finish when their work is completed.
  	 */
  	CSTATE_START_TX,
  
  	/*
  	 * In CSTATE_PREPARE_THROTTLE state, we calculate when to begin the next
  	 * transaction, and advance to CSTATE_THROTTLE.  CSTATE_THROTTLE state
  	 * sleeps until that moment, then advances to CSTATE_START_TX, or
  	 * CSTATE_FINISHED if the next transaction would start beyond the end of
  	 * the run.
  	 */
  	CSTATE_PREPARE_THROTTLE,
  	CSTATE_THROTTLE,
  
  	/*
  	 * We loop through these states, to process each command in the script:
  	 *
  	 * CSTATE_START_COMMAND starts the execution of a command.  On a SQL
  	 * command, the command is sent to the server, and we move to
  	 * CSTATE_WAIT_RESULT state.  On a \sleep meta-command, the timer is set,
  	 * and we enter the CSTATE_SLEEP state to wait for it to expire. Other
  	 * meta-commands are executed immediately.  If the command about to start
  	 * is actually beyond the end of the script, advance to CSTATE_END_TX.
  	 *
  	 * CSTATE_WAIT_RESULT waits until we get a result set back from the server
  	 * for the current command.
  	 *
  	 * CSTATE_SLEEP waits until the end of \sleep.
  	 *
  	 * CSTATE_END_COMMAND records the end-of-command timestamp, increments the
  	 * command counter, and loops back to CSTATE_START_COMMAND state.
  	 *
  	 * CSTATE_SKIP_COMMAND is used by conditional branches which are not
  	 * executed. It quickly skip commands that do not need any evaluation.
  	 * This state can move forward several commands, till there is something
  	 * to do or the end of the script.
  	 */
  	CSTATE_START_COMMAND,
  	CSTATE_WAIT_RESULT,
  	CSTATE_SLEEP,
  	CSTATE_END_COMMAND,
  	CSTATE_SKIP_COMMAND,
  
  	/*
  	 * CSTATE_END_TX performs end-of-transaction processing.  It calculates
  	 * latency, and logs the transaction.  In --connect mode, it closes the
  	 * current connection.
  	 *
  	 * Then either starts over in CSTATE_CHOOSE_SCRIPT, or enters
  	 * CSTATE_FINISHED if we have no more work to do.
  	 */
  	CSTATE_END_TX,
  
  	/*
  	 * Final states.  CSTATE_ABORTED means that the script execution was
  	 * aborted because a command failed, CSTATE_FINISHED means success.
  	 */
  	CSTATE_ABORTED,
  	CSTATE_FINISHED
  } ConnectionStateEnum;
  
  /*
   * Connection state.
   */
  typedef struct
  {
  	PGconn	   *con;			/* connection handle to DB */
  	int			id;				/* client No. */
  	ConnectionStateEnum state;	/* state machine's current state. */
  	ConditionalStack cstack;	/* enclosing conditionals state */
  
  	/*
  	 * Separate randomness for each client. This is used for random functions
  	 * PGBENCH_RANDOM_* during the execution of the script.
  	 */
  	RandomState cs_func_rs;
  
  	int			use_file;		/* index in sql_script for this client */
  	int			command;		/* command number in script */
  
  	/* client variables */
  	Variable   *variables;		/* array of variable definitions */
  	int			nvariables;		/* number of variables */
  	bool		vars_sorted;	/* are variables sorted by name? */
  
  	/* various times about current transaction */
  	int64		txn_scheduled;	/* scheduled start time of transaction (usec) */
  	int64		sleep_until;	/* scheduled start time of next cmd (usec) */
  	instr_time	txn_begin;		/* used for measuring schedule lag times */
  	instr_time	stmt_begin;		/* used for measuring statement latencies */
  
  	bool		prepared[MAX_SCRIPTS];	/* whether client prepared the script */
  
  	/* per client collected stats */
  	int64		cnt;			/* client transaction count, for -t */
  	int			ecnt;			/* error count */
  } CState;
  
  /*
   * Thread state
   */
  typedef struct
  {
  	int			tid;			/* thread id */
  	pthread_t	thread;			/* thread handle */
  	CState	   *state;			/* array of CState */
  	int			nstate;			/* length of state[] */
  
  	/*
  	 * Separate randomness for each thread. Each thread option uses its own
  	 * random state to make all of them independent of each other and therefore
  	 * deterministic at the thread level.
  	 */
  	RandomState ts_choose_rs;	/* random state for selecting a script */
  	RandomState ts_throttle_rs;	/* random state for transaction throttling */
  	RandomState ts_sample_rs;	/* random state for log sampling */
  
  	int64		throttle_trigger;	/* previous/next throttling (us) */
  	FILE	   *logfile;		/* where to log, or NULL */
  
  	/* per thread collected stats */
  	instr_time	start_time;		/* thread start time */
  	instr_time	conn_time;
  	StatsData	stats;
  	int64		latency_late;	/* executed but late transactions */
  } TState;
  
  #define INVALID_THREAD		((pthread_t) 0)
  
  /*
   * queries read from files
   */
  #define SQL_COMMAND		1
  #define META_COMMAND	2
  
  /*
   * max number of backslash command arguments or SQL variables,
   * including the command or SQL statement itself
   */
  #define MAX_ARGS		256
  
  typedef enum MetaCommand
  {
  	META_NONE,					/* not a known meta-command */
  	META_SET,					/* \set */
  	META_SETSHELL,				/* \setshell */
  	META_SHELL,					/* \shell */
  	META_SLEEP,					/* \sleep */
  	META_GSET,					/* \gset */
  	META_IF,					/* \if */
  	META_ELIF,					/* \elif */
  	META_ELSE,					/* \else */
  	META_ENDIF					/* \endif */
  } MetaCommand;
  
  typedef enum QueryMode
  {
  	QUERY_SIMPLE,				/* simple query */
  	QUERY_EXTENDED,				/* extended query */
  	QUERY_PREPARED,				/* extended query with prepared statements */
  	NUM_QUERYMODE
  } QueryMode;
  
  static QueryMode querymode = QUERY_SIMPLE;
  static const char *QUERYMODE[] = {"simple", "extended", "prepared"};
  
  /*
   * struct Command represents one command in a script.
   *
   * lines		The raw, possibly multi-line command text.  Variable substitution
   *				not applied.
   * first_line	A short, single-line extract of 'lines', for error reporting.
   * type			SQL_COMMAND or META_COMMAND
   * meta			The type of meta-command, or META_NONE if command is SQL
   * argc			Number of arguments of the command, 0 if not yet processed.
   * argv			Command arguments, the first of which is the command or SQL
   *				string itself.  For SQL commands, after post-processing
   *				argv[0] is the same as 'lines' with variables substituted.
   * varprefix 	SQL commands terminated with \gset have this set
   *				to a non NULL value.  If nonempty, it's used to prefix the
   *				variable name that receives the value.
   * expr			Parsed expression, if needed.
   * stats		Time spent in this command.
   */
  typedef struct Command
  {
  	PQExpBufferData lines;
  	char	   *first_line;
  	int			type;
  	MetaCommand meta;
  	int			argc;
  	char	   *argv[MAX_ARGS];
  	char	   *varprefix;
  	PgBenchExpr *expr;
  	SimpleStats stats;
  } Command;
  
  typedef struct ParsedScript
  {
  	const char *desc;			/* script descriptor (eg, file name) */
  	int			weight;			/* selection weight */
  	Command   **commands;		/* NULL-terminated array of Commands */
  	StatsData	stats;			/* total time spent in script */
  } ParsedScript;
  
  static ParsedScript sql_script[MAX_SCRIPTS];	/* SQL script files */
  static int	num_scripts;		/* number of scripts in sql_script[] */
  static int64 total_weight = 0;
  
  static int	debug = 0;			/* debug flag */
  
  /* Builtin test scripts */
  typedef struct BuiltinScript
  {
  	const char *name;			/* very short name for -b ... */
  	const char *desc;			/* short description */
  	const char *script;			/* actual pgbench script */
  } BuiltinScript;
  
  static const BuiltinScript builtin_script[] =
  {
  	{
  		"tpcb-like",
  		"<builtin: TPC-B (sort of)>",
  		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
  		"\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
  		"\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
  		"\\set delta random(-5000, 5000)\n"
  		"BEGIN;\n"
  		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
  		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
  		"UPDATE pgbench_tellers SET tbalance = tbalance + :delta WHERE tid = :tid;\n"
  		"UPDATE pgbench_branches SET bbalance = bbalance + :delta WHERE bid = :bid;\n"
  		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
  		"END;\n"
  	},
  	{
  		"simple-update",
  		"<builtin: simple update>",
  		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
  		"\\set bid random(1, " CppAsString2(nbranches) " * :scale)\n"
  		"\\set tid random(1, " CppAsString2(ntellers) " * :scale)\n"
  		"\\set delta random(-5000, 5000)\n"
  		"BEGIN;\n"
  		"UPDATE pgbench_accounts SET abalance = abalance + :delta WHERE aid = :aid;\n"
  		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
  		"INSERT INTO pgbench_history (tid, bid, aid, delta, mtime) VALUES (:tid, :bid, :aid, :delta, CURRENT_TIMESTAMP);\n"
  		"END;\n"
  	},
  	{
  		"select-only",
  		"<builtin: select only>",
  		"\\set aid random(1, " CppAsString2(naccounts) " * :scale)\n"
  		"SELECT abalance FROM pgbench_accounts WHERE aid = :aid;\n"
  	}
  };
  
  
  /* Function prototypes */
  static void setNullValue(PgBenchValue *pv);
  static void setBoolValue(PgBenchValue *pv, bool bval);
  static void setIntValue(PgBenchValue *pv, int64 ival);
  static void setDoubleValue(PgBenchValue *pv, double dval);
  static bool evaluateExpr(CState *st, PgBenchExpr *expr,
  			 PgBenchValue *retval);
  static ConnectionStateEnum executeMetaCommand(CState *st, instr_time *now);
  static void doLog(TState *thread, CState *st,
  	  StatsData *agg, bool skipped, double latency, double lag);
  static void processXactStats(TState *thread, CState *st, instr_time *now,
  				 bool skipped, StatsData *agg);
  static void addScript(ParsedScript script);
  static void *threadRun(void *arg);
  static void finishCon(CState *st);
  static void setalarm(int seconds);
  static socket_set *alloc_socket_set(int count);
  static void free_socket_set(socket_set *sa);
  static void clear_socket_set(socket_set *sa);
  static void add_socket_to_set(socket_set *sa, int fd, int idx);
  static int	wait_on_socket_set(socket_set *sa, int64 usecs);
  static bool socket_has_input(socket_set *sa, int fd, int idx);
  
  
  /* callback functions for our flex lexer */
  static const PsqlScanCallbacks pgbench_callbacks = {
  	NULL,						/* don't need get_variable functionality */
  };
  
  
  static void
  usage(void)
  {
  	printf("%s is a benchmarking tool for PostgreSQL.\n\n"
  		   "Usage:\n"
  		   "  %s [OPTION]... [DBNAME]\n"
  		   "\nInitialization options:\n"
  		   "  -i, --initialize         invokes initialization mode\n"
  		   "  -I, --init-steps=[dtgvpf]+ (default \"dtgvp\")\n"
  		   "                           run selected initialization steps\n"
  		   "  -F, --fillfactor=NUM     set fill factor\n"
  		   "  -n, --no-vacuum          do not run VACUUM during initialization\n"
  		   "  -q, --quiet              quiet logging (one message each 5 seconds)\n"
  		   "  -s, --scale=NUM          scaling factor\n"
  		   "  --foreign-keys           create foreign key constraints between tables\n"
  		   "  --index-tablespace=TABLESPACE\n"
  		   "                           create indexes in the specified tablespace\n"
  		   "  --tablespace=TABLESPACE  create tables in the specified tablespace\n"
  		   "  --unlogged-tables        create tables as unlogged tables\n"
  		   "\nOptions to select what to run:\n"
  		   "  -b, --builtin=NAME[@W]   add builtin script NAME weighted at W (default: 1)\n"
  		   "                           (use \"-b list\" to list available scripts)\n"
  		   "  -f, --file=FILENAME[@W]  add script FILENAME weighted at W (default: 1)\n"
  		   "  -N, --skip-some-updates  skip updates of pgbench_tellers and pgbench_branches\n"
  		   "                           (same as \"-b simple-update\")\n"
  		   "  -S, --select-only        perform SELECT-only transactions\n"
  		   "                           (same as \"-b select-only\")\n"
  		   "\nBenchmarking options:\n"
  		   "  -c, --client=NUM         number of concurrent database clients (default: 1)\n"
  		   "  -C, --connect            establish new connection for each transaction\n"
  		   "  -D, --define=VARNAME=VALUE\n"
  		   "                           define variable for use by custom script\n"
  		   "  -j, --jobs=NUM           number of threads (default: 1)\n"
  		   "  -l, --log                write transaction times to log file\n"
  		   "  -L, --latency-limit=NUM  count transactions lasting more than NUM ms as late\n"
  		   "  -M, --protocol=simple|extended|prepared\n"
  		   "                           protocol for submitting queries (default: simple)\n"
  		   "  -n, --no-vacuum          do not run VACUUM before tests\n"
  		   "  -P, --progress=NUM       show thread progress report every NUM seconds\n"
  		   "  -r, --report-latencies   report average latency per command\n"
  		   "  -R, --rate=NUM           target rate in transactions per second\n"
  		   "  -s, --scale=NUM          report this scale factor in output\n"
  		   "  -t, --transactions=NUM   number of transactions each client runs (default: 10)\n"
  		   "  -T, --time=NUM           duration of benchmark test in seconds\n"
  		   "  -v, --vacuum-all         vacuum all four standard tables before tests\n"
  		   "  --aggregate-interval=NUM aggregate data over NUM seconds\n"
  		   "  --log-prefix=PREFIX      prefix for transaction time log file\n"
  		   "                           (default: \"pgbench_log\")\n"
  		   "  --progress-timestamp     use Unix epoch timestamps for progress\n"
  		   "  --random-seed=SEED       set random seed (\"time\", \"rand\", integer)\n"
  		   "  --sampling-rate=NUM      fraction of transactions to log (e.g., 0.01 for 1%%)\n"
  		   "\nCommon options:\n"
  		   "  -d, --debug              print debugging output\n"
  		   "  -h, --host=HOSTNAME      database server host or socket directory\n"
  		   "  -p, --port=PORT          database server port number\n"
  		   "  -U, --username=USERNAME  connect as specified database user\n"
  		   "  -V, --version            output version information, then exit\n"
  		   "  -?, --help               show this help, then exit\n"
  		   "\n"
  		   "Report bugs to <pgsql-bugs@lists.postgresql.org>.\n",
  		   progname, progname);
  }
  
  /* return whether str matches "^\s*[-+]?[0-9]+$" */
  static bool
  is_an_int(const char *str)
  {
  	const char *ptr = str;
  
  	/* skip leading spaces; cast is consistent with strtoint64 */
  	while (*ptr && isspace((unsigned char) *ptr))
  		ptr++;
  
  	/* skip sign */
  	if (*ptr == '+' || *ptr == '-')
  		ptr++;
  
  	/* at least one digit */
  	if (*ptr && !isdigit((unsigned char) *ptr))
  		return false;
  
  	/* eat all digits */
  	while (*ptr && isdigit((unsigned char) *ptr))
  		ptr++;
  
  	/* must have reached end of string */
  	return *ptr == '\0';
  }
  
  
  /*
   * strtoint64 -- convert a string to 64-bit integer
   *
   * This function is a slightly modified version of scanint8() from
   * src/backend/utils/adt/int8.c.
   *
   * The function returns whether the conversion worked, and if so
   * "*result" is set to the result.
   *
   * If not errorOK, an error message is also printed out on errors.
   */
  bool
  strtoint64(const char *str, bool errorOK, int64 *result)
  {
  	const char *ptr = str;
  	int64		tmp = 0;
  	bool		neg = false;
  
  	/*
  	 * Do our own scan, rather than relying on sscanf which might be broken
  	 * for long long.
  	 *
  	 * As INT64_MIN can't be stored as a positive 64 bit integer, accumulate
  	 * value as a negative number.
  	 */
  
  	/* skip leading spaces */
  	while (*ptr && isspace((unsigned char) *ptr))
  		ptr++;
  
  	/* handle sign */
  	if (*ptr == '-')
  	{
  		ptr++;
  		neg = true;
  	}
  	else if (*ptr == '+')
  		ptr++;
  
  	/* require at least one digit */
  	if (unlikely(!isdigit((unsigned char) *ptr)))
  		goto invalid_syntax;
  
  	/* process digits */
  	while (*ptr && isdigit((unsigned char) *ptr))
  	{
  		int8		digit = (*ptr++ - '0');
  
  		if (unlikely(pg_mul_s64_overflow(tmp, 10, &tmp)) ||
  			unlikely(pg_sub_s64_overflow(tmp, digit, &tmp)))
  			goto out_of_range;
  	}
  
  	/* allow trailing whitespace, but not other trailing chars */
  	while (*ptr != '\0' && isspace((unsigned char) *ptr))
  		ptr++;
  
  	if (unlikely(*ptr != '\0'))
  		goto invalid_syntax;
  
  	if (!neg)
  	{
  		if (unlikely(tmp == PG_INT64_MIN))
  			goto out_of_range;
  		tmp = -tmp;
  	}
  
  	*result = tmp;
  	return true;
  
  out_of_range:
  	if (!errorOK)
  		fprintf(stderr,
  				"value \"%s\" is out of range for type bigint\n", str);
  	return false;
  
  invalid_syntax:
  	if (!errorOK)
  		fprintf(stderr,
  				"invalid input syntax for type bigint: \"%s\"\n", str);
  	return false;
  }
  
  /* convert string to double, detecting overflows/underflows */
  bool
  strtodouble(const char *str, bool errorOK, double *dv)
  {
  	char *end;
  
  	errno = 0;
  	*dv = strtod(str, &end);
  
  	if (unlikely(errno != 0))
  	{
  		if (!errorOK)
  			fprintf(stderr,
  					"value \"%s\" is out of range for type double\n", str);
  		return false;
  	}
  
  	if (unlikely(end == str || *end != '\0'))
  	{
  		if (!errorOK)
  			fprintf(stderr,
  					"invalid input syntax for type double: \"%s\"\n", str);
  		return false;
  	}
  	return true;
  }
  
  /*
   * Initialize a random state struct.
   *
   * We derive the seed from base_random_sequence, which must be set up already.
   */
  static void
  initRandomState(RandomState *random_state)
  {
  	random_state->xseed[0] = (unsigned short)
  		(pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
  	random_state->xseed[1] = (unsigned short)
  		(pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
  	random_state->xseed[2] = (unsigned short)
  		(pg_jrand48(base_random_sequence.xseed) & 0xFFFF);
  }
  
  /*
   * Random number generator: uniform distribution from min to max inclusive.
   *
   * Although the limits are expressed as int64, you can't generate the full
   * int64 range in one call, because the difference of the limits mustn't
   * overflow int64.  In practice it's unwise to ask for more than an int32
   * range, because of the limited precision of pg_erand48().
   */
  static int64
  getrand(RandomState *random_state, int64 min, int64 max)
  {
  	/*
  	 * Odd coding is so that min and max have approximately the same chance of
  	 * being selected as do numbers between them.
  	 *
  	 * pg_erand48() is thread-safe and concurrent, which is why we use it
  	 * rather than random(), which in glibc is non-reentrant, and therefore
  	 * protected by a mutex, and therefore a bottleneck on machines with many
  	 * CPUs.
  	 */
  	return min + (int64) ((max - min + 1) * pg_erand48(random_state->xseed));
  }
  
  /*
   * random number generator: exponential distribution from min to max inclusive.
   * the parameter is so that the density of probability for the last cut-off max
   * value is exp(-parameter).
   */
  static int64
  getExponentialRand(RandomState *random_state, int64 min, int64 max,
  				   double parameter)
  {
  	double		cut,
  				uniform,
  				rand;
  
  	/* abort if wrong parameter, but must really be checked beforehand */
  	Assert(parameter > 0.0);
  	cut = exp(-parameter);
  	/* erand in [0, 1), uniform in (0, 1] */
  	uniform = 1.0 - pg_erand48(random_state->xseed);
  
  	/*
  	 * inner expression in (cut, 1] (if parameter > 0), rand in [0, 1)
  	 */
  	Assert((1.0 - cut) != 0.0);
  	rand = -log(cut + (1.0 - cut) * uniform) / parameter;
  	/* return int64 random number within between min and max */
  	return min + (int64) ((max - min + 1) * rand);
  }
  
  /* random number generator: gaussian distribution from min to max inclusive */
  static int64
  getGaussianRand(RandomState *random_state, int64 min, int64 max,
  				double parameter)
  {
  	double		stdev;
  	double		rand;
  
  	/* abort if parameter is too low, but must really be checked beforehand */
  	Assert(parameter >= MIN_GAUSSIAN_PARAM);
  
  	/*
  	 * Get user specified random number from this loop, with -parameter <
  	 * stdev <= parameter
  	 *
  	 * This loop is executed until the number is in the expected range.
  	 *
  	 * As the minimum parameter is 2.0, the probability of looping is low:
  	 * sqrt(-2 ln(r)) <= 2 => r >= e^{-2} ~ 0.135, then when taking the
  	 * average sinus multiplier as 2/pi, we have a 8.6% looping probability in
  	 * the worst case. For a parameter value of 5.0, the looping probability
  	 * is about e^{-5} * 2 / pi ~ 0.43%.
  	 */
  	do
  	{
  		/*
  		 * pg_erand48 generates [0,1), but for the basic version of the
  		 * Box-Muller transform the two uniformly distributed random numbers
  		 * are expected in (0, 1] (see
  		 * https://en.wikipedia.org/wiki/Box-Muller_transform)
  		 */
  		double		rand1 = 1.0 - pg_erand48(random_state->xseed);
  		double		rand2 = 1.0 - pg_erand48(random_state->xseed);
  
  		/* Box-Muller basic form transform */
  		double		var_sqrt = sqrt(-2.0 * log(rand1));
  
  		stdev = var_sqrt * sin(2.0 * M_PI * rand2);
  
  		/*
  		 * we may try with cos, but there may be a bias induced if the
  		 * previous value fails the test. To be on the safe side, let us try
  		 * over.
  		 */
  	}
  	while (stdev < -parameter || stdev >= parameter);
  
  	/* stdev is in [-parameter, parameter), normalization to [0,1) */
  	rand = (stdev + parameter) / (parameter * 2.0);
  
  	/* return int64 random number within between min and max */
  	return min + (int64) ((max - min + 1) * rand);
  }
  
  /*
   * random number generator: generate a value, such that the series of values
   * will approximate a Poisson distribution centered on the given value.
   *
   * Individual results are rounded to integers, though the center value need
   * not be one.
   */
  static int64
  getPoissonRand(RandomState *random_state, double center)
  {
  	/*
  	 * Use inverse transform sampling to generate a value > 0, such that the
  	 * expected (i.e. average) value is the given argument.
  	 */
  	double		uniform;
  
  	/* erand in [0, 1), uniform in (0, 1] */
  	uniform = 1.0 - pg_erand48(random_state->xseed);
  
  	return (int64) (-log(uniform) * center + 0.5);
  }
  
  /*
   * Computing zipfian using rejection method, based on
   * "Non-Uniform Random Variate Generation",
   * Luc Devroye, p. 550-551, Springer 1986.
   *
   * This works for s > 1.0, but may perform badly for s very close to 1.0.
   */
  static int64
  computeIterativeZipfian(RandomState *random_state, int64 n, double s)
  {
  	double		b = pow(2.0, s - 1.0);
  	double		x,
  				t,
  				u,
  				v;
  
  	/* Ensure n is sane */
  	if (n <= 1)
  		return 1;
  
  	while (true)
  	{
  		/* random variates */
  		u = pg_erand48(random_state->xseed);
  		v = pg_erand48(random_state->xseed);
  
  		x = floor(pow(u, -1.0 / (s - 1.0)));
  
  		t = pow(1.0 + 1.0 / x, s - 1.0);
  		/* reject if too large or out of bound */
  		if (v * x * (t - 1.0) / (b - 1.0) <= t / b && x <= n)
  			break;
  	}
  	return (int64) x;
  }
  
  /* random number generator: zipfian distribution from min to max inclusive */
  static int64
  getZipfianRand(RandomState *random_state, int64 min, int64 max, double s)
  {
  	int64		n = max - min + 1;
  
  	/* abort if parameter is invalid */
  	Assert(MIN_ZIPFIAN_PARAM <= s && s <= MAX_ZIPFIAN_PARAM);
  
  	return min - 1 + computeIterativeZipfian(random_state, n, s);
  }
  
  /*
   * FNV-1a hash function
   */
  static int64
  getHashFnv1a(int64 val, uint64 seed)
  {
  	int64		result;
  	int			i;
  
  	result = FNV_OFFSET_BASIS ^ seed;
  	for (i = 0; i < 8; ++i)
  	{
  		int32		octet = val & 0xff;
  
  		val = val >> 8;
  		result = result ^ octet;
  		result = result * FNV_PRIME;
  	}
  
  	return result;
  }
  
  /*
   * Murmur2 hash function
   *
   * Based on original work of Austin Appleby
   * https://github.com/aappleby/smhasher/blob/master/src/MurmurHash2.cpp
   */
  static int64
  getHashMurmur2(int64 val, uint64 seed)
  {
  	uint64		result = seed ^ MM2_MUL_TIMES_8;	/* sizeof(int64) */
  	uint64		k = (uint64) val;
  
  	k *= MM2_MUL;
  	k ^= k >> MM2_ROT;
  	k *= MM2_MUL;
  
  	result ^= k;
  	result *= MM2_MUL;
  
  	result ^= result >> MM2_ROT;
  	result *= MM2_MUL;
  	result ^= result >> MM2_ROT;
  
  	return (int64) result;
  }
  
  /*
   * Initialize the given SimpleStats struct to all zeroes
   */
  static void
  initSimpleStats(SimpleStats *ss)
  {
  	memset(ss, 0, sizeof(SimpleStats));
  }
  
  /*
   * Accumulate one value into a SimpleStats struct.
   */
  static void
  addToSimpleStats(SimpleStats *ss, double val)
  {
  	if (ss->count == 0 || val < ss->min)
  		ss->min = val;
  	if (ss->count == 0 || val > ss->max)
  		ss->max = val;
  	ss->count++;
  	ss->sum += val;
  	ss->sum2 += val * val;
  }
  
  /*
   * Merge two SimpleStats objects
   */
  static void
  mergeSimpleStats(SimpleStats *acc, SimpleStats *ss)
  {
  	if (acc->count == 0 || ss->min < acc->min)
  		acc->min = ss->min;
  	if (acc->count == 0 || ss->max > acc->max)
  		acc->max = ss->max;
  	acc->count += ss->count;
  	acc->sum += ss->sum;
  	acc->sum2 += ss->sum2;
  }
  
  /*
   * Initialize a StatsData struct to mostly zeroes, with its start time set to
   * the given value.
   */
  static void
  initStats(StatsData *sd, time_t start_time)
  {
  	sd->start_time = start_time;
  	sd->cnt = 0;
  	sd->skipped = 0;
  	initSimpleStats(&sd->latency);
  	initSimpleStats(&sd->lag);
  }
  
  /*
   * Accumulate one additional item into the given stats object.
   */
  static void
  accumStats(StatsData *stats, bool skipped, double lat, double lag)
  {
  	stats->cnt++;
  
  	if (skipped)
  	{
  		/* no latency to record on skipped transactions */
  		stats->skipped++;
  	}
  	else
  	{
  		addToSimpleStats(&stats->latency, lat);
  
  		/* and possibly the same for schedule lag */
  		if (throttle_delay)
  			addToSimpleStats(&stats->lag, lag);
  	}
  }
  
  /* call PQexec() and exit() on failure */
  static void
  executeStatement(PGconn *con, const char *sql)
  {
  	PGresult   *res;
  
  	res = PQexec(con, sql);
  	if (PQresultStatus(res) != PGRES_COMMAND_OK)
  	{
  		fprintf(stderr, "%s", PQerrorMessage(con));
  		exit(1);
  	}
  	PQclear(res);
  }
  
  /* call PQexec() and complain, but without exiting, on failure */
  static void
  tryExecuteStatement(PGconn *con, const char *sql)
  {
  	PGresult   *res;
  
  	res = PQexec(con, sql);
  	if (PQresultStatus(res) != PGRES_COMMAND_OK)
  	{
  		fprintf(stderr, "%s", PQerrorMessage(con));
  		fprintf(stderr, "(ignoring this error and continuing anyway)\n");
  	}
  	PQclear(res);
  }
  
  /* set up a connection to the backend */
  static PGconn *
  doConnect(void)
  {
  	PGconn	   *conn;
  	bool		new_pass;
  	static bool have_password = false;
  	static char password[100];
  
  	/*
  	 * Start the connection.  Loop until we have a password if requested by
  	 * backend.
  	 */
  	do
  	{
  #define PARAMS_ARRAY_SIZE	7
  
  		const char *keywords[PARAMS_ARRAY_SIZE];
  		const char *values[PARAMS_ARRAY_SIZE];
  
  		keywords[0] = "host";
  		values[0] = pghost;
  		keywords[1] = "port";
  		values[1] = pgport;
  		keywords[2] = "user";
  		values[2] = login;
  		keywords[3] = "password";
  		values[3] = have_password ? password : NULL;
  		keywords[4] = "dbname";
  		values[4] = dbName;
  		keywords[5] = "fallback_application_name";
  		values[5] = progname;
  		keywords[6] = NULL;
  		values[6] = NULL;
  
  		new_pass = false;
  
  		conn = PQconnectdbParams(keywords, values, true);
  
  		if (!conn)
  		{
  			fprintf(stderr, "connection to database \"%s\" failed\n",
  					dbName);
  			return NULL;
  		}
  
  		if (PQstatus(conn) == CONNECTION_BAD &&
  			PQconnectionNeedsPassword(conn) &&
  			!have_password)
  		{
  			PQfinish(conn);
  			simple_prompt("Password: ", password, sizeof(password), false);
  			have_password = true;
  			new_pass = true;
  		}
  	} while (new_pass);
  
  	/* check to see that the backend connection was successfully made */
  	if (PQstatus(conn) == CONNECTION_BAD)
  	{
  		fprintf(stderr, "connection to database \"%s\" failed:\n%s",
  				dbName, PQerrorMessage(conn));
  		PQfinish(conn);
  		return NULL;
  	}
  
  	return conn;
  }
  
  /* qsort comparator for Variable array */
  static int
  compareVariableNames(const void *v1, const void *v2)
  {
  	return strcmp(((const Variable *) v1)->name,
  				  ((const Variable *) v2)->name);
  }
  
  /* Locate a variable by name; returns NULL if unknown */
  static Variable *
  lookupVariable(CState *st, char *name)
  {
  	Variable	key;
  
  	/* On some versions of Solaris, bsearch of zero items dumps core */
  	if (st->nvariables <= 0)
  		return NULL;
  
  	/* Sort if we have to */
  	if (!st->vars_sorted)
  	{
  		qsort((void *) st->variables, st->nvariables, sizeof(Variable),
  			  compareVariableNames);
  		st->vars_sorted = true;
  	}
  
  	/* Now we can search */
  	key.name = name;
  	return (Variable *) bsearch((void *) &key,
  								(void *) st->variables,
  								st->nvariables,
  								sizeof(Variable),
  								compareVariableNames);
  }
  
  /* Get the value of a variable, in string form; returns NULL if unknown */
  static char *
  getVariable(CState *st, char *name)
  {
  	Variable   *var;
  	char		stringform[64];
  
  	var = lookupVariable(st, name);
  	if (var == NULL)
  		return NULL;			/* not found */
  
  	if (var->svalue)
  		return var->svalue;		/* we have it in string form */
  
  	/* We need to produce a string equivalent of the value */
  	Assert(var->value.type != PGBT_NO_VALUE);
  	if (var->value.type == PGBT_NULL)
  		snprintf(stringform, sizeof(stringform), "NULL");
  	else if (var->value.type == PGBT_BOOLEAN)
  		snprintf(stringform, sizeof(stringform),
  				 "%s", var->value.u.bval ? "true" : "false");
  	else if (var->value.type == PGBT_INT)
  		snprintf(stringform, sizeof(stringform),
  				 INT64_FORMAT, var->value.u.ival);
  	else if (var->value.type == PGBT_DOUBLE)
  		snprintf(stringform, sizeof(stringform),
  				 "%.*g", DBL_DIG, var->value.u.dval);
  	else						/* internal error, unexpected type */
  		Assert(0);
  	var->svalue = pg_strdup(stringform);
  	return var->svalue;
  }
  
  /* Try to convert variable to a value; return false on failure */
  static bool
  makeVariableValue(Variable *var)
  {
  	size_t		slen;
  
  	if (var->value.type != PGBT_NO_VALUE)
  		return true;			/* no work */
  
  	slen = strlen(var->svalue);
  
  	if (slen == 0)
  		/* what should it do on ""? */
  		return false;
  
  	if (pg_strcasecmp(var->svalue, "null") == 0)
  	{
  		setNullValue(&var->value);
  	}
  
  	/*
  	 * accept prefixes such as y, ye, n, no... but not for "o". 0/1 are
  	 * recognized later as an int, which is converted to bool if needed.
  	 */
  	else if (pg_strncasecmp(var->svalue, "true", slen) == 0 ||
  			 pg_strncasecmp(var->svalue, "yes", slen) == 0 ||
  			 pg_strcasecmp(var->svalue, "on") == 0)
  	{
  		setBoolValue(&var->value, true);
  	}
  	else if (pg_strncasecmp(var->svalue, "false", slen) == 0 ||
  			 pg_strncasecmp(var->svalue, "no", slen) == 0 ||
  			 pg_strcasecmp(var->svalue, "off") == 0 ||
  			 pg_strcasecmp(var->svalue, "of") == 0)
  	{
  		setBoolValue(&var->value, false);
  	}
  	else if (is_an_int(var->svalue))
  	{
  		/* if it looks like an int, it must be an int without overflow */
  		int64 iv;
  
  		if (!strtoint64(var->svalue, false, &iv))
  			return false;
  
  		setIntValue(&var->value, iv);
  	}
  	else						/* type should be double */
  	{
  		double		dv;
  
  		if (!strtodouble(var->svalue, true, &dv))
  		{
  			fprintf(stderr,
  					"malformed variable \"%s\" value: \"%s\"\n",
  					var->name, var->svalue);
  			return false;
  		}
  		setDoubleValue(&var->value, dv);
  	}
  	return true;
  }
  
  /*
   * Check whether a variable's name is allowed.
   *
   * We allow any non-ASCII character, as well as ASCII letters, digits, and
   * underscore.
   *
   * Keep this in sync with the definitions of variable name characters in
   * "src/fe_utils/psqlscan.l", "src/bin/psql/psqlscanslash.l" and
   * "src/bin/pgbench/exprscan.l".  Also see parseVariable(), below.
   *
   * Note: this static function is copied from "src/bin/psql/variables.c"
   */
  static bool
  valid_variable_name(const char *name)
  {
  	const unsigned char *ptr = (const unsigned char *) name;
  
  	/* Mustn't be zero-length */
  	if (*ptr == '\0')
  		return false;
  
  	while (*ptr)
  	{
  		if (IS_HIGHBIT_SET(*ptr) ||
  			strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
  				   "_0123456789", *ptr) != NULL)
  			ptr++;
  		else
  			return false;
  	}
  
  	return true;
  }
  
  /*
   * Lookup a variable by name, creating it if need be.
   * Caller is expected to assign a value to the variable.
   * Returns NULL on failure (bad name).
   */
  static Variable *
  lookupCreateVariable(CState *st, const char *context, char *name)
  {
  	Variable   *var;
  
  	var = lookupVariable(st, name);
  	if (var == NULL)
  	{
  		Variable   *newvars;
  
  		/*
  		 * Check for the name only when declaring a new variable to avoid
  		 * overhead.
  		 */
  		if (!valid_variable_name(name))
  		{
  			fprintf(stderr, "%s: invalid variable name: \"%s\"\n",
  					context, name);
  			return NULL;
  		}
  
  		/* Create variable at the end of the array */
  		if (st->variables)
  			newvars = (Variable *) pg_realloc(st->variables,
  											  (st->nvariables + 1) * sizeof(Variable));
  		else
  			newvars = (Variable *) pg_malloc(sizeof(Variable));
  
  		st->variables = newvars;
  
  		var = &newvars[st->nvariables];
  
  		var->name = pg_strdup(name);
  		var->svalue = NULL;
  		/* caller is expected to initialize remaining fields */
  
  		st->nvariables++;
  		/* we don't re-sort the array till we have to */
  		st->vars_sorted = false;
  	}
  
  	return var;
  }
  
  /* Assign a string value to a variable, creating it if need be */
  /* Returns false on failure (bad name) */
  static bool
  putVariable(CState *st, const char *context, char *name, const char *value)
  {
  	Variable   *var;
  	char	   *val;
  
  	var = lookupCreateVariable(st, context, name);
  	if (!var)
  		return false;
  
  	/* dup then free, in case value is pointing at this variable */
  	val = pg_strdup(value);
  
  	if (var->svalue)
  		free(var->svalue);
  	var->svalue = val;
  	var->value.type = PGBT_NO_VALUE;
  
  	return true;
  }
  
  /* Assign a value to a variable, creating it if need be */
  /* Returns false on failure (bad name) */
  static bool
  putVariableValue(CState *st, const char *context, char *name,
  				 const PgBenchValue *value)
  {
  	Variable   *var;
  
  	var = lookupCreateVariable(st, context, name);
  	if (!var)
  		return false;
  
  	if (var->svalue)
  		free(var->svalue);
  	var->svalue = NULL;
  	var->value = *value;
  
  	return true;
  }
  
  /* Assign an integer value to a variable, creating it if need be */
  /* Returns false on failure (bad name) */
  static bool
  putVariableInt(CState *st, const char *context, char *name, int64 value)
  {
  	PgBenchValue val;
  
  	setIntValue(&val, value);
  	return putVariableValue(st, context, name, &val);
  }
  
  /*
   * Parse a possible variable reference (:varname).
   *
   * "sql" points at a colon.  If what follows it looks like a valid
   * variable name, return a malloc'd string containing the variable name,
   * and set *eaten to the number of characters consumed.
   * Otherwise, return NULL.
   */
  static char *
  parseVariable(const char *sql, int *eaten)
  {
  	int			i = 0;
  	char	   *name;
  
  	do
  	{
  		i++;
  	} while (IS_HIGHBIT_SET(sql[i]) ||
  			 strchr("ABCDEFGHIJKLMNOPQRSTUVWXYZ" "abcdefghijklmnopqrstuvwxyz"
  					"_0123456789", sql[i]) != NULL);
  	if (i == 1)
  		return NULL;			/* no valid variable name chars */
  
  	name = pg_malloc(i);
  	memcpy(name, &sql[1], i - 1);
  	name[i - 1] = '\0';
  
  	*eaten = i;
  	return name;
  }
  
  static char *
  replaceVariable(char **sql, char *param, int len, char *value)
  {
  	int			valueln = strlen(value);
  
  	if (valueln > len)
  	{
  		size_t		offset = param - *sql;
  
  		*sql = pg_realloc(*sql, strlen(*sql) - len + valueln + 1);
  		param = *sql + offset;
  	}
  
  	if (valueln != len)
  		memmove(param + valueln, param + len, strlen(param + len) + 1);
  	memcpy(param, value, valueln);
  
  	return param + valueln;
  }
  
  static char *
  assignVariables(CState *st, char *sql)
  {
  	char	   *p,
  			   *name,
  			   *val;
  
  	p = sql;
  	while ((p = strchr(p, ':')) != NULL)
  	{
  		int			eaten;
  
  		name = parseVariable(p, &eaten);
  		if (name == NULL)
  		{
  			while (*p == ':')
  			{
  				p++;
  			}
  			continue;
  		}
  
  		val = getVariable(st, name);
  		free(name);
  		if (val == NULL)
  		{
  			p++;
  			continue;
  		}
  
  		p = replaceVariable(&sql, p, eaten, val);
  	}
  
  	return sql;
  }
  
  static void
  getQueryParams(CState *st, const Command *command, const char **params)
  {
  	int			i;
  
  	for (i = 0; i < command->argc - 1; i++)
  		params[i] = getVariable(st, command->argv[i + 1]);
  }
  
  static char *
  valueTypeName(PgBenchValue *pval)
  {
  	if (pval->type == PGBT_NO_VALUE)
  		return "none";
  	else if (pval->type == PGBT_NULL)
  		return "null";
  	else if (pval->type == PGBT_INT)
  		return "int";
  	else if (pval->type == PGBT_DOUBLE)
  		return "double";
  	else if (pval->type == PGBT_BOOLEAN)
  		return "boolean";
  	else
  	{
  		/* internal error, should never get there */
  		Assert(false);
  		return NULL;
  	}
  }
  
  /* get a value as a boolean, or tell if there is a problem */
  static bool
  coerceToBool(PgBenchValue *pval, bool *bval)
  {
  	if (pval->type == PGBT_BOOLEAN)
  	{
  		*bval = pval->u.bval;
  		return true;
  	}
  	else						/* NULL, INT or DOUBLE */
  	{
  		fprintf(stderr, "cannot coerce %s to boolean\n", valueTypeName(pval));
  		*bval = false;			/* suppress uninitialized-variable warnings */
  		return false;
  	}
  }
  
  /*
   * Return true or false from an expression for conditional purposes.
   * Non zero numerical values are true, zero and NULL are false.
   */
  static bool
  valueTruth(PgBenchValue *pval)
  {
  	switch (pval->type)
  	{
  		case PGBT_NULL:
  			return false;
  		case PGBT_BOOLEAN:
  			return pval->u.bval;
  		case PGBT_INT:
  			return pval->u.ival != 0;
  		case PGBT_DOUBLE:
  			return pval->u.dval != 0.0;
  		default:
  			/* internal error, unexpected type */
  			Assert(0);
  			return false;
  	}
  }
  
  /* get a value as an int, tell if there is a problem */
  static bool
  coerceToInt(PgBenchValue *pval, int64 *ival)
  {
  	if (pval->type == PGBT_INT)
  	{
  		*ival = pval->u.ival;
  		return true;
  	}
  	else if (pval->type == PGBT_DOUBLE)
  	{
  		double		dval = pval->u.dval;
  
  		if (dval < PG_INT64_MIN || PG_INT64_MAX < dval)
  		{
  			fprintf(stderr, "double to int overflow for %f\n", dval);
  			return false;
  		}
  		*ival = (int64) dval;
  		return true;
  	}
  	else						/* BOOLEAN or NULL */
  	{
  		fprintf(stderr, "cannot coerce %s to int\n", valueTypeName(pval));
  		return false;
  	}
  }
  
  /* get a value as a double, or tell if there is a problem */
  static bool
  coerceToDouble(PgBenchValue *pval, double *dval)
  {
  	if (pval->type == PGBT_DOUBLE)
  	{
  		*dval = pval->u.dval;
  		return true;
  	}
  	else if (pval->type == PGBT_INT)
  	{
  		*dval = (double) pval->u.ival;
  		return true;
  	}
  	else						/* BOOLEAN or NULL */
  	{
  		fprintf(stderr, "cannot coerce %s to double\n", valueTypeName(pval));
  		return false;
  	}
  }
  
  /* assign a null value */
  static void
  setNullValue(PgBenchValue *pv)
  {
  	pv->type = PGBT_NULL;
  	pv->u.ival = 0;
  }
  
  /* assign a boolean value */
  static void
  setBoolValue(PgBenchValue *pv, bool bval)
  {
  	pv->type = PGBT_BOOLEAN;
  	pv->u.bval = bval;
  }
  
  /* assign an integer value */
  static void
  setIntValue(PgBenchValue *pv, int64 ival)
  {
  	pv->type = PGBT_INT;
  	pv->u.ival = ival;
  }
  
  /* assign a double value */
  static void
  setDoubleValue(PgBenchValue *pv, double dval)
  {
  	pv->type = PGBT_DOUBLE;
  	pv->u.dval = dval;
  }
  
  static bool
  isLazyFunc(PgBenchFunction func)
  {
  	return func == PGBENCH_AND || func == PGBENCH_OR || func == PGBENCH_CASE;
  }
  
  /* lazy evaluation of some functions */
  static bool
  evalLazyFunc(CState *st,
  			 PgBenchFunction func, PgBenchExprLink *args, PgBenchValue *retval)
  {
  	PgBenchValue a1,
  				a2;
  	bool		ba1,
  				ba2;
  
  	Assert(isLazyFunc(func) && args != NULL && args->next != NULL);
  
  	/* args points to first condition */
  	if (!evaluateExpr(st, args->expr, &a1))
  		return false;
  
  	/* second condition for AND/OR and corresponding branch for CASE */
  	args = args->next;
  
  	switch (func)
  	{
  		case PGBENCH_AND:
  			if (a1.type == PGBT_NULL)
  			{
  				setNullValue(retval);
  				return true;
  			}
  
  			if (!coerceToBool(&a1, &ba1))
  				return false;
  
  			if (!ba1)
  			{
  				setBoolValue(retval, false);
  				return true;
  			}
  
  			if (!evaluateExpr(st, args->expr, &a2))
  				return false;
  
  			if (a2.type == PGBT_NULL)
  			{
  				setNullValue(retval);
  				return true;
  			}
  			else if (!coerceToBool(&a2, &ba2))
  				return false;
  			else
  			{
  				setBoolValue(retval, ba2);
  				return true;
  			}
  
  			return true;
  
  		case PGBENCH_OR:
  
  			if (a1.type == PGBT_NULL)
  			{
  				setNullValue(retval);
  				return true;
  			}
  
  			if (!coerceToBool(&a1, &ba1))
  				return false;
  
  			if (ba1)
  			{
  				setBoolValue(retval, true);
  				return true;
  			}
  
  			if (!evaluateExpr(st, args->expr, &a2))
  				return false;
  
  			if (a2.type == PGBT_NULL)
  			{
  				setNullValue(retval);
  				return true;
  			}
  			else if (!coerceToBool(&a2, &ba2))
  				return false;
  			else
  			{
  				setBoolValue(retval, ba2);
  				return true;
  			}
  
  		case PGBENCH_CASE:
  			/* when true, execute branch */
  			if (valueTruth(&a1))
  				return evaluateExpr(st, args->expr, retval);
  
  			/* now args contains next condition or final else expression */
  			args = args->next;
  
  			/* final else case? */
  			if (args->next == NULL)
  				return evaluateExpr(st, args->expr, retval);
  
  			/* no, another when, proceed */
  			return evalLazyFunc(st, PGBENCH_CASE, args, retval);
  
  		default:
  			/* internal error, cannot get here */
  			Assert(0);
  			break;
  	}
  	return false;
  }
  
  /* maximum number of function arguments */
  #define MAX_FARGS 16
  
  /*
   * Recursive evaluation of standard functions,
   * which do not require lazy evaluation.
   */
  static bool
  evalStandardFunc(CState *st,
  				 PgBenchFunction func, PgBenchExprLink *args,
  				 PgBenchValue *retval)
  {
  	/* evaluate all function arguments */
  	int			nargs = 0;
  	PgBenchValue vargs[MAX_FARGS];
  	PgBenchExprLink *l = args;
  	bool		has_null = false;
  
  	for (nargs = 0; nargs < MAX_FARGS && l != NULL; nargs++, l = l->next)
  	{
  		if (!evaluateExpr(st, l->expr, &vargs[nargs]))
  			return false;
  		has_null |= vargs[nargs].type == PGBT_NULL;
  	}
  
  	if (l != NULL)
  	{
  		fprintf(stderr,
  				"too many function arguments, maximum is %d\n", MAX_FARGS);
  		return false;
  	}
  
  	/* NULL arguments */
  	if (has_null && func != PGBENCH_IS && func != PGBENCH_DEBUG)
  	{
  		setNullValue(retval);
  		return true;
  	}
  
  	/* then evaluate function */
  	switch (func)
  	{
  			/* overloaded operators */
  		case PGBENCH_ADD:
  		case PGBENCH_SUB:
  		case PGBENCH_MUL:
  		case PGBENCH_DIV:
  		case PGBENCH_MOD:
  		case PGBENCH_EQ:
  		case PGBENCH_NE:
  		case PGBENCH_LE:
  		case PGBENCH_LT:
  			{
  				PgBenchValue *lval = &vargs[0],
  						   *rval = &vargs[1];
  
  				Assert(nargs == 2);
  
  				/* overloaded type management, double if some double */
  				if ((lval->type == PGBT_DOUBLE ||
  					 rval->type == PGBT_DOUBLE) && func != PGBENCH_MOD)
  				{
  					double		ld,
  								rd;
  
  					if (!coerceToDouble(lval, &ld) ||
  						!coerceToDouble(rval, &rd))
  						return false;
  
  					switch (func)
  					{
  						case PGBENCH_ADD:
  							setDoubleValue(retval, ld + rd);
  							return true;
  
  						case PGBENCH_SUB:
  							setDoubleValue(retval, ld - rd);
  							return true;
  
  						case PGBENCH_MUL:
  							setDoubleValue(retval, ld * rd);
  							return true;
  
  						case PGBENCH_DIV:
  							setDoubleValue(retval, ld / rd);
  							return true;
  
  						case PGBENCH_EQ:
  							setBoolValue(retval, ld == rd);
  							return true;
  
  						case PGBENCH_NE:
  							setBoolValue(retval, ld != rd);
  							return true;
  
  						case PGBENCH_LE:
  							setBoolValue(retval, ld <= rd);
  							return true;
  
  						case PGBENCH_LT:
  							setBoolValue(retval, ld < rd);
  							return true;
  
  						default:
  							/* cannot get here */
  							Assert(0);
  					}
  				}
  				else			/* we have integer operands, or % */
  				{
  					int64		li,
  								ri,
  								res;
  
  					if (!coerceToInt(lval, &li) ||
  						!coerceToInt(rval, &ri))
  						return false;
  
  					switch (func)
  					{
  						case PGBENCH_ADD:
  							if (pg_add_s64_overflow(li, ri, &res))
  							{
  								fprintf(stderr, "bigint add out of range\n");
  								return false;
  							}
  							setIntValue(retval, res);
  							return true;
  
  						case PGBENCH_SUB:
  							if (pg_sub_s64_overflow(li, ri, &res))
  							{
  								fprintf(stderr, "bigint sub out of range\n");
  								return false;
  							}
  							setIntValue(retval, res);
  							return true;
  
  						case PGBENCH_MUL:
  							if (pg_mul_s64_overflow(li, ri, &res))
  							{
  								fprintf(stderr, "bigint mul out of range\n");
  								return false;
  							}
  							setIntValue(retval, res);
  							return true;
  
  						case PGBENCH_EQ:
  							setBoolValue(retval, li == ri);
  							return true;
  
  						case PGBENCH_NE:
  							setBoolValue(retval, li != ri);
  							return true;
  
  						case PGBENCH_LE:
  							setBoolValue(retval, li <= ri);
  							return true;
  
  						case PGBENCH_LT:
  							setBoolValue(retval, li < ri);
  							return true;
  
  						case PGBENCH_DIV:
  						case PGBENCH_MOD:
  							if (ri == 0)
  							{
  								fprintf(stderr, "division by zero\n");
  								return false;
  							}
  							/* special handling of -1 divisor */
  							if (ri == -1)
  							{
  								if (func == PGBENCH_DIV)
  								{
  									/* overflow check (needed for INT64_MIN) */
  									if (li == PG_INT64_MIN)
  									{
  										fprintf(stderr, "bigint div out of range\n");
  										return false;
  									}
  									else
  										setIntValue(retval, -li);
  								}
  								else
  									setIntValue(retval, 0);
  								return true;
  							}
  							/* else divisor is not -1 */
  							if (func == PGBENCH_DIV)
  								setIntValue(retval, li / ri);
  							else	/* func == PGBENCH_MOD */
  								setIntValue(retval, li % ri);
  
  							return true;
  
  						default:
  							/* cannot get here */
  							Assert(0);
  					}
  				}
  
  				Assert(0);
  				return false;	/* NOTREACHED */
  			}
  
  			/* integer bitwise operators */
  		case PGBENCH_BITAND:
  		case PGBENCH_BITOR:
  		case PGBENCH_BITXOR:
  		case PGBENCH_LSHIFT:
  		case PGBENCH_RSHIFT:
  			{
  				int64		li,
  							ri;
  
  				if (!coerceToInt(&vargs[0], &li) || !coerceToInt(&vargs[1], &ri))
  					return false;
  
  				if (func == PGBENCH_BITAND)
  					setIntValue(retval, li & ri);
  				else if (func == PGBENCH_BITOR)
  					setIntValue(retval, li | ri);
  				else if (func == PGBENCH_BITXOR)
  					setIntValue(retval, li ^ ri);
  				else if (func == PGBENCH_LSHIFT)
  					setIntValue(retval, li << ri);
  				else if (func == PGBENCH_RSHIFT)
  					setIntValue(retval, li >> ri);
  				else			/* cannot get here */
  					Assert(0);
  
  				return true;
  			}
  
  			/* logical operators */
  		case PGBENCH_NOT:
  			{
  				bool		b;
  
  				if (!coerceToBool(&vargs[0], &b))
  					return false;
  
  				setBoolValue(retval, !b);
  				return true;
  			}
  
  			/* no arguments */
  		case PGBENCH_PI:
  			setDoubleValue(retval, M_PI);
  			return true;
  
  			/* 1 overloaded argument */
  		case PGBENCH_ABS:
  			{
  				PgBenchValue *varg = &vargs[0];
  
  				Assert(nargs == 1);
  
  				if (varg->type == PGBT_INT)
  				{
  					int64		i = varg->u.ival;
  
  					setIntValue(retval, i < 0 ? -i : i);
  				}
  				else
  				{
  					double		d = varg->u.dval;
  
  					Assert(varg->type == PGBT_DOUBLE);
  					setDoubleValue(retval, d < 0.0 ? -d : d);
  				}
  
  				return true;
  			}
  
  		case PGBENCH_DEBUG:
  			{
  				PgBenchValue *varg = &vargs[0];
  
  				Assert(nargs == 1);
  
  				fprintf(stderr, "debug(script=%d,command=%d): ",
  						st->use_file, st->command + 1);
  
  				if (varg->type == PGBT_NULL)
  					fprintf(stderr, "null\n");
  				else if (varg->type == PGBT_BOOLEAN)
  					fprintf(stderr, "boolean %s\n", varg->u.bval ? "true" : "false");
  				else if (varg->type == PGBT_INT)
  					fprintf(stderr, "int " INT64_FORMAT "\n", varg->u.ival);
  				else if (varg->type == PGBT_DOUBLE)
  					fprintf(stderr, "double %.*g\n", DBL_DIG, varg->u.dval);
  				else			/* internal error, unexpected type */
  					Assert(0);
  
  				*retval = *varg;
  
  				return true;
  			}
  
  			/* 1 double argument */
  		case PGBENCH_DOUBLE:
  		case PGBENCH_SQRT:
  		case PGBENCH_LN:
  		case PGBENCH_EXP:
  			{
  				double		dval;
  
  				Assert(nargs == 1);
  
  				if (!coerceToDouble(&vargs[0], &dval))
  					return false;
  
  				if (func == PGBENCH_SQRT)
  					dval = sqrt(dval);
  				else if (func == PGBENCH_LN)
  					dval = log(dval);
  				else if (func == PGBENCH_EXP)
  					dval = exp(dval);
  				/* else is cast: do nothing */
  
  				setDoubleValue(retval, dval);
  				return true;
  			}
  
  			/* 1 int argument */
  		case PGBENCH_INT:
  			{
  				int64		ival;
  
  				Assert(nargs == 1);
  
  				if (!coerceToInt(&vargs[0], &ival))
  					return false;
  
  				setIntValue(retval, ival);
  				return true;
  			}
  
  			/* variable number of arguments */
  		case PGBENCH_LEAST:
  		case PGBENCH_GREATEST:
  			{
  				bool		havedouble;
  				int			i;
  
  				Assert(nargs >= 1);
  
  				/* need double result if any input is double */
  				havedouble = false;
  				for (i = 0; i < nargs; i++)
  				{
  					if (vargs[i].type == PGBT_DOUBLE)
  					{
  						havedouble = true;
  						break;
  					}
  				}
  				if (havedouble)
  				{
  					double		extremum;
  
  					if (!coerceToDouble(&vargs[0], &extremum))
  						return false;
  					for (i = 1; i < nargs; i++)
  					{
  						double		dval;
  
  						if (!coerceToDouble(&vargs[i], &dval))
  							return false;
  						if (func == PGBENCH_LEAST)
  							extremum = Min(extremum, dval);
  						else
  							extremum = Max(extremum, dval);
  					}
  					setDoubleValue(retval, extremum);
  				}
  				else
  				{
  					int64		extremum;
  
  					if (!coerceToInt(&vargs[0], &extremum))
  						return false;
  					for (i = 1; i < nargs; i++)
  					{
  						int64		ival;
  
  						if (!coerceToInt(&vargs[i], &ival))
  							return false;
  						if (func == PGBENCH_LEAST)
  							extremum = Min(extremum, ival);
  						else
  							extremum = Max(extremum, ival);
  					}
  					setIntValue(retval, extremum);
  				}
  				return true;
  			}
  
  			/* random functions */
  		case PGBENCH_RANDOM:
  		case PGBENCH_RANDOM_EXPONENTIAL:
  		case PGBENCH_RANDOM_GAUSSIAN:
  		case PGBENCH_RANDOM_ZIPFIAN:
  			{
  				int64		imin,
  							imax;
  
  				Assert(nargs >= 2);
  
  				if (!coerceToInt(&vargs[0], &imin) ||
  					!coerceToInt(&vargs[1], &imax))
  					return false;
  
  				/* check random range */
  				if (imin > imax)
  				{
  					fprintf(stderr, "empty range given to random\n");
  					return false;
  				}
  				else if (imax - imin < 0 || (imax - imin) + 1 < 0)
  				{
  					/* prevent int overflows in random functions */
  					fprintf(stderr, "random range is too large\n");
  					return false;
  				}
  
  				if (func == PGBENCH_RANDOM)
  				{
  					Assert(nargs == 2);
  					setIntValue(retval, getrand(&st->cs_func_rs, imin, imax));
  				}
  				else			/* gaussian & exponential */
  				{
  					double		param;
  
  					Assert(nargs == 3);
  
  					if (!coerceToDouble(&vargs[2], &param))
  						return false;
  
  					if (func == PGBENCH_RANDOM_GAUSSIAN)
  					{
  						if (param < MIN_GAUSSIAN_PARAM)
  						{
  							fprintf(stderr,
  									"gaussian parameter must be at least %f "
  									"(not %f)\n", MIN_GAUSSIAN_PARAM, param);
  							return false;
  						}
  
  						setIntValue(retval,
  									getGaussianRand(&st->cs_func_rs,
  													imin, imax, param));
  					}
  					else if (func == PGBENCH_RANDOM_ZIPFIAN)
  					{
  						if (param < MIN_ZIPFIAN_PARAM || param > MAX_ZIPFIAN_PARAM)
  						{
  							fprintf(stderr,
  									"zipfian parameter must be in range [%.3f, %.0f]"
  									" (not %f)\n",
  									MIN_ZIPFIAN_PARAM, MAX_ZIPFIAN_PARAM, param);
  							return false;
  						}
  
  						setIntValue(retval,
  									getZipfianRand(&st->cs_func_rs, imin, imax, param));
  					}
  					else		/* exponential */
  					{
  						if (param <= 0.0)
  						{
  							fprintf(stderr,
  									"exponential parameter must be greater than zero"
  									" (not %f)\n", param);
  							return false;
  						}
  
  						setIntValue(retval,
  									getExponentialRand(&st->cs_func_rs,
  													   imin, imax, param));
  					}
  				}
  
  				return true;
  			}
  
  		case PGBENCH_POW:
  			{
  				PgBenchValue *lval = &vargs[0];
  				PgBenchValue *rval = &vargs[1];
  				double		ld,
  							rd;
  
  				Assert(nargs == 2);
  
  				if (!coerceToDouble(lval, &ld) ||
  					!coerceToDouble(rval, &rd))
  					return false;
  
  				setDoubleValue(retval, pow(ld, rd));
  
  				return true;
  			}
  
  		case PGBENCH_IS:
  			{
  				Assert(nargs == 2);
  
  				/*
  				 * note: this simple implementation is more permissive than
  				 * SQL
  				 */
  				setBoolValue(retval,
  							 vargs[0].type == vargs[1].type &&
  							 vargs[0].u.bval == vargs[1].u.bval);
  				return true;
  			}
  
  			/* hashing */
  		case PGBENCH_HASH_FNV1A:
  		case PGBENCH_HASH_MURMUR2:
  			{
  				int64		val,
  							seed;
  
  				Assert(nargs == 2);
  
  				if (!coerceToInt(&vargs[0], &val) ||
  					!coerceToInt(&vargs[1], &seed))
  					return false;
  
  				if (func == PGBENCH_HASH_MURMUR2)
  					setIntValue(retval, getHashMurmur2(val, seed));
  				else if (func == PGBENCH_HASH_FNV1A)
  					setIntValue(retval, getHashFnv1a(val, seed));
  				else
  					/* cannot get here */
  					Assert(0);
  
  				return true;
  			}
  
  		default:
  			/* cannot get here */
  			Assert(0);
  			/* dead code to avoid a compiler warning */
  			return false;
  	}
  }
  
  /* evaluate some function */
  static bool
  evalFunc(CState *st,
  		 PgBenchFunction func, PgBenchExprLink *args, PgBenchValue *retval)
  {
  	if (isLazyFunc(func))
  		return evalLazyFunc(st, func, args, retval);
  	else
  		return evalStandardFunc(st, func, args, retval);
  }
  
  /*
   * Recursive evaluation of an expression in a pgbench script
   * using the current state of variables.
   * Returns whether the evaluation was ok,
   * the value itself is returned through the retval pointer.
   */
  static bool
  evaluateExpr(CState *st, PgBenchExpr *expr, PgBenchValue *retval)
  {
  	switch (expr->etype)
  	{
  		case ENODE_CONSTANT:
  			{
  				*retval = expr->u.constant;
  				return true;
  			}
  
  		case ENODE_VARIABLE:
  			{
  				Variable   *var;
  
  				if ((var = lookupVariable(st, expr->u.variable.varname)) == NULL)
  				{
  					fprintf(stderr, "undefined variable \"%s\"\n",
  							expr->u.variable.varname);
  					return false;
  				}
  
  				if (!makeVariableValue(var))
  					return false;
  
  				*retval = var->value;
  				return true;
  			}
  
  		case ENODE_FUNCTION:
  			return evalFunc(st,
  							expr->u.function.function,
  							expr->u.function.args,
  							retval);
  
  		default:
  			/* internal error which should never occur */
  			fprintf(stderr, "unexpected enode type in evaluation: %d\n",
  					expr->etype);
  			exit(1);
  	}
  }
  
  /*
   * Convert command name to meta-command enum identifier
   */
  static MetaCommand
  getMetaCommand(const char *cmd)
  {
  	MetaCommand mc;
  
  	if (cmd == NULL)
  		mc = META_NONE;
  	else if (pg_strcasecmp(cmd, "set") == 0)
  		mc = META_SET;
  	else if (pg_strcasecmp(cmd, "setshell") == 0)
  		mc = META_SETSHELL;
  	else if (pg_strcasecmp(cmd, "shell") == 0)
  		mc = META_SHELL;
  	else if (pg_strcasecmp(cmd, "sleep") == 0)
  		mc = META_SLEEP;
  	else if (pg_strcasecmp(cmd, "if") == 0)
  		mc = META_IF;
  	else if (pg_strcasecmp(cmd, "elif") == 0)
  		mc = META_ELIF;
  	else if (pg_strcasecmp(cmd, "else") == 0)
  		mc = META_ELSE;
  	else if (pg_strcasecmp(cmd, "endif") == 0)
  		mc = META_ENDIF;
  	else if (pg_strcasecmp(cmd, "gset") == 0)
  		mc = META_GSET;
  	else
  		mc = META_NONE;
  	return mc;
  }
  
  /*
   * Run a shell command. The result is assigned to the variable if not NULL.
   * Return true if succeeded, or false on error.
   */
  static bool
  runShellCommand(CState *st, char *variable, char **argv, int argc)
  {
  	char		command[SHELL_COMMAND_SIZE];
  	int			i,
  				len = 0;
  	FILE	   *fp;
  	char		res[64];
  	char	   *endptr;
  	int			retval;
  
  	/*----------
  	 * Join arguments with whitespace separators. Arguments starting with
  	 * exactly one colon are treated as variables:
  	 *	name - append a string "name"
  	 *	:var - append a variable named 'var'
  	 *	::name - append a string ":name"
  	 *----------
  	 */
  	for (i = 0; i < argc; i++)
  	{
  		char	   *arg;
  		int			arglen;
  
  		if (argv[i][0] != ':')
  		{
  			arg = argv[i];		/* a string literal */
  		}
  		else if (argv[i][1] == ':')
  		{
  			arg = argv[i] + 1;	/* a string literal starting with colons */
  		}
  		else if ((arg = getVariable(st, argv[i] + 1)) == NULL)
  		{
  			fprintf(stderr, "%s: undefined variable \"%s\"\n",
  					argv[0], argv[i]);
  			return false;
  		}
  
  		arglen = strlen(arg);
  		if (len + arglen + (i > 0 ? 1 : 0) >= SHELL_COMMAND_SIZE - 1)
  		{
  			fprintf(stderr, "%s: shell command is too long\n", argv[0]);
  			return false;
  		}
  
  		if (i > 0)
  			command[len++] = ' ';
  		memcpy(command + len, arg, arglen);
  		len += arglen;
  	}
  
  	command[len] = '\0';
  
  	/* Fast path for non-assignment case */
  	if (variable == NULL)
  	{
  		if (system(command))
  		{
  			if (!timer_exceeded)
  				fprintf(stderr, "%s: could not launch shell command\n", argv[0]);
  			return false;
  		}
  		return true;
  	}
  
  	/* Execute the command with pipe and read the standard output. */
  	if ((fp = popen(command, "r")) == NULL)
  	{
  		fprintf(stderr, "%s: could not launch shell command\n", argv[0]);
  		return false;
  	}
  	if (fgets(res, sizeof(res), fp) == NULL)
  	{
  		if (!timer_exceeded)
  			fprintf(stderr, "%s: could not read result of shell command\n", argv[0]);
  		(void) pclose(fp);
  		return false;
  	}
  	if (pclose(fp) < 0)
  	{
  		fprintf(stderr, "%s: could not close shell command\n", argv[0]);
  		return false;
  	}
  
  	/* Check whether the result is an integer and assign it to the variable */
  	retval = (int) strtol(res, &endptr, 10);
  	while (*endptr != '\0' && isspace((unsigned char) *endptr))
  		endptr++;
  	if (*res == '\0' || *endptr != '\0')
  	{
  		fprintf(stderr, "%s: shell command must return an integer (not \"%s\")\n",
  				argv[0], res);
  		return false;
  	}
  	if (!putVariableInt(st, "setshell", variable, retval))
  		return false;
  
  #ifdef DEBUG
  	printf("shell parameter name: \"%s\", value: \"%s\"\n", argv[1], res);
  #endif
  	return true;
  }
  
  #define MAX_PREPARE_NAME		32
  static void
  preparedStatementName(char *buffer, int file, int state)
  {
  	sprintf(buffer, "P%d_%d", file, state);
  }
  
  static void
  commandFailed(CState *st, const char *cmd, const char *message)
  {
  	fprintf(stderr,
  			"client %d aborted in command %d (%s) of script %d; %s\n",
  			st->id, st->command, cmd, st->use_file, message);
  }
  
  /* return a script number with a weighted choice. */
  static int
  chooseScript(TState *thread)
  {
  	int			i = 0;
  	int64		w;
  
  	if (num_scripts == 1)
  		return 0;
  
  	w = getrand(&thread->ts_choose_rs, 0, total_weight - 1);
  	do
  	{
  		w -= sql_script[i++].weight;
  	} while (w >= 0);
  
  	return i - 1;
  }
  
  /* Send a SQL command, using the chosen querymode */
  static bool
  sendCommand(CState *st, Command *command)
  {
  	int			r;
  
  	if (querymode == QUERY_SIMPLE)
  	{
  		char	   *sql;
  
  		sql = pg_strdup(command->argv[0]);
  		sql = assignVariables(st, sql);
  
  		if (debug)
  			fprintf(stderr, "client %d sending %s\n", st->id, sql);
  		r = PQsendQuery(st->con, sql);
  		free(sql);
  	}
  	else if (querymode == QUERY_EXTENDED)
  	{
  		const char *sql = command->argv[0];
  		const char *params[MAX_ARGS];
  
  		getQueryParams(st, command, params);
  
  		if (debug)
  			fprintf(stderr, "client %d sending %s\n", st->id, sql);
  		r = PQsendQueryParams(st->con, sql, command->argc - 1,
  							  NULL, params, NULL, NULL, 0);
  	}
  	else if (querymode == QUERY_PREPARED)
  	{
  		char		name[MAX_PREPARE_NAME];
  		const char *params[MAX_ARGS];
  
  		if (!st->prepared[st->use_file])
  		{
  			int			j;
  			Command   **commands = sql_script[st->use_file].commands;
  
  			for (j = 0; commands[j] != NULL; j++)
  			{
  				PGresult   *res;
  				char		name[MAX_PREPARE_NAME];
  
  				if (commands[j]->type != SQL_COMMAND)
  					continue;
  				preparedStatementName(name, st->use_file, j);
  				res = PQprepare(st->con, name,
  								commands[j]->argv[0], commands[j]->argc - 1, NULL);
  				if (PQresultStatus(res) != PGRES_COMMAND_OK)
  					fprintf(stderr, "%s", PQerrorMessage(st->con));
  				PQclear(res);
  			}
  			st->prepared[st->use_file] = true;
  		}
  
  		getQueryParams(st, command, params);
  		preparedStatementName(name, st->use_file, st->command);
  
  		if (debug)
  			fprintf(stderr, "client %d sending %s\n", st->id, name);
  		r = PQsendQueryPrepared(st->con, name, command->argc - 1,
  								params, NULL, NULL, 0);
  	}
  	else						/* unknown sql mode */
  		r = 0;
  
  	if (r == 0)
  	{
  		if (debug)
  			fprintf(stderr, "client %d could not send %s\n",
  					st->id, command->argv[0]);
  		st->ecnt++;
  		return false;
  	}
  	else
  		return true;
  }
  
  /*
   * Process query response from the backend.
   *
   * If varprefix is not NULL, it's the variable name prefix where to store
   * the results of the *last* command.
   *
   * Returns true if everything is A-OK, false if any error occurs.
   */
  static bool
  readCommandResponse(CState *st, char *varprefix)
  {
  	PGresult   *res;
  	PGresult   *next_res;
  	int			qrynum = 0;
  
  	res = PQgetResult(st->con);
  
  	while (res != NULL)
  	{
  		bool	is_last;
  
  		/* peek at the next result to know whether the current is last */
  		next_res = PQgetResult(st->con);
  		is_last = (next_res == NULL);
  
  		switch (PQresultStatus(res))
  		{
  			case PGRES_COMMAND_OK:	/* non-SELECT commands */
  			case PGRES_EMPTY_QUERY: /* may be used for testing no-op overhead */
  				if (is_last && varprefix != NULL)
  				{
  					fprintf(stderr,
  							"client %d script %d command %d query %d: expected one row, got %d\n",
  							st->id, st->use_file, st->command, qrynum, 0);
  					goto error;
  				}
  				break;
  
  			case PGRES_TUPLES_OK:
  				if (is_last && varprefix != NULL)
  				{
  					if (PQntuples(res) != 1)
  					{
  						fprintf(stderr,
  								"client %d script %d command %d query %d: expected one row, got %d\n",
  								st->id, st->use_file, st->command, qrynum, PQntuples(res));
  						goto error;
  					}
  
  					/* store results into variables */
  					for (int fld = 0; fld < PQnfields(res); fld++)
  					{
  						char	   *varname = PQfname(res, fld);
  
  						/* allocate varname only if necessary, freed below */
  						if (*varprefix != '\0')
  							varname = psprintf("%s%s", varprefix, varname);
  
  						/* store result as a string */
  						if (!putVariable(st, "gset", varname,
  										 PQgetvalue(res, 0, fld)))
  						{
  							/* internal error */
  							fprintf(stderr,
  									"client %d script %d command %d query %d: error storing into variable %s\n",
  									st->id, st->use_file, st->command, qrynum,
  									varname);
  							goto error;
  						}
  
  						if (*varprefix != '\0')
  							pg_free(varname);
  					}
  				}
  				/* otherwise the result is simply thrown away by PQclear below */
  				break;
  
  			default:
  				/* anything else is unexpected */
  				fprintf(stderr,
  						"client %d script %d aborted in command %d query %d: %s",
  						st->id, st->use_file, st->command, qrynum,
  						PQerrorMessage(st->con));
  				goto error;
  		}
  
  		PQclear(res);
  		qrynum++;
  		res = next_res;
  	}
  
  	if (qrynum == 0)
  	{
  		fprintf(stderr, "client %d command %d: no results\n", st->id, st->command);
  		st->ecnt++;
  		return false;
  	}
  
  	return true;
  
  error:
  	st->ecnt++;
  	PQclear(res);
  	PQclear(next_res);
  	do
  	{
  		res = PQgetResult(st->con);
  		PQclear(res);
  	} while (res);
  
  	return false;
  }
  
  /*
   * Parse the argument to a \sleep command, and return the requested amount
   * of delay, in microseconds.  Returns true on success, false on error.
   */
  static bool
  evaluateSleep(CState *st, int argc, char **argv, int *usecs)
  {
  	char	   *var;
  	int			usec;
  
  	if (*argv[1] == ':')
  	{
  		if ((var = getVariable(st, argv[1] + 1)) == NULL)
  		{
  			fprintf(stderr, "%s: undefined variable \"%s\"\n",
  					argv[0], argv[1]);
  			return false;
  		}
  		usec = atoi(var);
  	}
  	else
  		usec = atoi(argv[1]);
  
  	if (argc > 2)
  	{
  		if (pg_strcasecmp(argv[2], "ms") == 0)
  			usec *= 1000;
  		else if (pg_strcasecmp(argv[2], "s") == 0)
  			usec *= 1000000;
  	}
  	else
  		usec *= 1000000;
  
  	*usecs = usec;
  	return true;
  }
  
  /*
   * Advance the state machine of a connection.
   */
  static void
  advanceConnectionState(TState *thread, CState *st, StatsData *agg)
  {
  	instr_time	now;
  
  	/*
  	 * gettimeofday() isn't free, so we get the current timestamp lazily the
  	 * first time it's needed, and reuse the same value throughout this
  	 * function after that.  This also ensures that e.g. the calculated
  	 * latency reported in the log file and in the totals are the same. Zero
  	 * means "not set yet".  Reset "now" when we execute shell commands or
  	 * expressions, which might take a non-negligible amount of time, though.
  	 */
  	INSTR_TIME_SET_ZERO(now);
  
  	/*
  	 * Loop in the state machine, until we have to wait for a result from the
  	 * server or have to sleep for throttling or \sleep.
  	 *
  	 * Note: In the switch-statement below, 'break' will loop back here,
  	 * meaning "continue in the state machine".  Return is used to return to
  	 * the caller, giving the thread the opportunity to advance another
  	 * client.
  	 */
  	for (;;)
  	{
  		Command    *command;
  
  		switch (st->state)
  		{
  				/* Select transaction (script) to run.  */
  			case CSTATE_CHOOSE_SCRIPT:
  				st->use_file = chooseScript(thread);
  				Assert(conditional_stack_empty(st->cstack));
  
  				if (debug)
  					fprintf(stderr, "client %d executing script \"%s\"\n", st->id,
  							sql_script[st->use_file].desc);
  
  				/*
  				 * If time is over, we're done; otherwise, get ready to start
  				 * a new transaction, or to get throttled if that's requested.
  				 */
  				st->state = timer_exceeded ? CSTATE_FINISHED :
  					throttle_delay > 0 ? CSTATE_PREPARE_THROTTLE : CSTATE_START_TX;
  				break;
  
  				/* Start new transaction (script) */
  			case CSTATE_START_TX:
  
  				/* establish connection if needed, i.e. under --connect */
  				if (st->con == NULL)
  				{
  					instr_time	start;
  
  					INSTR_TIME_SET_CURRENT_LAZY(now);
  					start = now;
  					if ((st->con = doConnect()) == NULL)
  					{
  						fprintf(stderr, "client %d aborted while establishing connection\n",
  								st->id);
  						st->state = CSTATE_ABORTED;
  						break;
  					}
  					INSTR_TIME_SET_CURRENT(now);
  					INSTR_TIME_ACCUM_DIFF(thread->conn_time, now, start);
  
  					/* Reset session-local state */
  					memset(st->prepared, 0, sizeof(st->prepared));
  				}
  
  				/* record transaction start time */
  				INSTR_TIME_SET_CURRENT_LAZY(now);
  				st->txn_begin = now;
  
  				/*
  				 * When not throttling, this is also the transaction's
  				 * scheduled start time.
  				 */
  				if (!throttle_delay)
  					st->txn_scheduled = INSTR_TIME_GET_MICROSEC(now);
  
  				/* Begin with the first command */
  				st->state = CSTATE_START_COMMAND;
  				st->command = 0;
  				break;
  
  				/*
  				 * Handle throttling once per transaction by sleeping.
  				 */
  			case CSTATE_PREPARE_THROTTLE:
  
  				/*
  				 * Generate a delay such that the series of delays will
  				 * approximate a Poisson distribution centered on the
  				 * throttle_delay time.
  				 *
  				 * If transactions are too slow or a given wait is shorter
  				 * than a transaction, the next transaction will start right
  				 * away.
  				 */
  				Assert(throttle_delay > 0);
  
  				thread->throttle_trigger +=
  					getPoissonRand(&thread->ts_throttle_rs, throttle_delay);
  				st->txn_scheduled = thread->throttle_trigger;
  
  				/*
  				 * If --latency-limit is used, and this slot is already late
  				 * so that the transaction will miss the latency limit even if
  				 * it completed immediately, skip this time slot and schedule
  				 * to continue running on the next slot that isn't late yet.
  				 * But don't iterate beyond the -t limit, if one is given.
  				 */
  				if (latency_limit)
  				{
  					int64		now_us;
  
  					INSTR_TIME_SET_CURRENT_LAZY(now);
  					now_us = INSTR_TIME_GET_MICROSEC(now);
  
  					while (thread->throttle_trigger < now_us - latency_limit &&
  						   (nxacts <= 0 || st->cnt < nxacts))
  					{
  						processXactStats(thread, st, &now, true, agg);
  						/* next rendez-vous */
  						thread->throttle_trigger +=
  							getPoissonRand(&thread->ts_throttle_rs, throttle_delay);
  						st->txn_scheduled = thread->throttle_trigger;
  					}
  
  					/*
  					 * stop client if -t was exceeded in the previous skip
  					 * loop
  					 */
  					if (nxacts > 0 && st->cnt >= nxacts)
  					{
  						st->state = CSTATE_FINISHED;
  						break;
  					}
  				}
  
  				/*
  				 * stop client if next transaction is beyond pgbench end of
  				 * execution; otherwise, throttle it.
  				 */
  				st->state = end_time > 0 && st->txn_scheduled > end_time ?
  					CSTATE_FINISHED : CSTATE_THROTTLE;
  				break;
  
  				/*
  				 * Wait until it's time to start next transaction.
  				 */
  			case CSTATE_THROTTLE:
  				INSTR_TIME_SET_CURRENT_LAZY(now);
  
  				if (INSTR_TIME_GET_MICROSEC(now) < st->txn_scheduled)
  					return;		/* still sleeping, nothing to do here */
  
  				/* done sleeping, but don't start transaction if we're done */
  				st->state = timer_exceeded ? CSTATE_FINISHED : CSTATE_START_TX;
  				break;
  
  				/*
  				 * Send a command to server (or execute a meta-command)
  				 */
  			case CSTATE_START_COMMAND:
  				command = sql_script[st->use_file].commands[st->command];
  
  				/* Transition to script end processing if done */
  				if (command == NULL)
  				{
  					st->state = CSTATE_END_TX;
  					break;
  				}
  
  				/* record begin time of next command, and initiate it */
  				if (report_per_command)
  				{
  					INSTR_TIME_SET_CURRENT_LAZY(now);
  					st->stmt_begin = now;
  				}
  
  				/* Execute the command */
  				if (command->type == SQL_COMMAND)
  				{
  					if (!sendCommand(st, command))
  					{
  						commandFailed(st, "SQL", "SQL command send failed");
  						st->state = CSTATE_ABORTED;
  					}
  					else
  						st->state = CSTATE_WAIT_RESULT;
  				}
  				else if (command->type == META_COMMAND)
  				{
  					/*-----
  					 * Possible state changes when executing meta commands:
  					 * - on errors CSTATE_ABORTED
  					 * - on sleep CSTATE_SLEEP
  					 * - else CSTATE_END_COMMAND
  					 */
  					st->state = executeMetaCommand(st, &now);
  				}
  
  				/*
  				 * We're now waiting for an SQL command to complete, or
  				 * finished processing a metacommand, or need to sleep, or
  				 * something bad happened.
  				 */
  				Assert(st->state == CSTATE_WAIT_RESULT ||
  					   st->state == CSTATE_END_COMMAND ||
  					   st->state == CSTATE_SLEEP ||
  					   st->state == CSTATE_ABORTED);
  				break;
  
  				/*
  				 * non executed conditional branch
  				 */
  			case CSTATE_SKIP_COMMAND:
  				Assert(!conditional_active(st->cstack));
  				/* quickly skip commands until something to do... */
  				while (true)
  				{
  					Command    *command;
  
  					command = sql_script[st->use_file].commands[st->command];
  
  					/* cannot reach end of script in that state */
  					Assert(command != NULL);
  
  					/*
  					 * if this is conditional related, update conditional
  					 * state
  					 */
  					if (command->type == META_COMMAND &&
  						(command->meta == META_IF ||
  						 command->meta == META_ELIF ||
  						 command->meta == META_ELSE ||
  						 command->meta == META_ENDIF))
  					{
  						switch (conditional_stack_peek(st->cstack))
  						{
  							case IFSTATE_FALSE:
  								if (command->meta == META_IF ||
  									command->meta == META_ELIF)
  								{
  									/* we must evaluate the condition */
  									st->state = CSTATE_START_COMMAND;
  								}
  								else if (command->meta == META_ELSE)
  								{
  									/* we must execute next command */
  									conditional_stack_poke(st->cstack,
  														   IFSTATE_ELSE_TRUE);
  									st->state = CSTATE_START_COMMAND;
  									st->command++;
  								}
  								else if (command->meta == META_ENDIF)
  								{
  									Assert(!conditional_stack_empty(st->cstack));
  									conditional_stack_pop(st->cstack);
  									if (conditional_active(st->cstack))
  										st->state = CSTATE_START_COMMAND;
  
  									/*
  									 * else state remains in
  									 * CSTATE_SKIP_COMMAND
  									 */
  									st->command++;
  								}
  								break;
  
  							case IFSTATE_IGNORED:
  							case IFSTATE_ELSE_FALSE:
  								if (command->meta == META_IF)
  									conditional_stack_push(st->cstack,
  														   IFSTATE_IGNORED);
  								else if (command->meta == META_ENDIF)
  								{
  									Assert(!conditional_stack_empty(st->cstack));
  									conditional_stack_pop(st->cstack);
  									if (conditional_active(st->cstack))
  										st->state = CSTATE_START_COMMAND;
  								}
  								/* could detect "else" & "elif" after "else" */
  								st->command++;
  								break;
  
  							case IFSTATE_NONE:
  							case IFSTATE_TRUE:
  							case IFSTATE_ELSE_TRUE:
  							default:
  
  								/*
  								 * inconsistent if inactive, unreachable dead
  								 * code
  								 */
  								Assert(false);
  						}
  					}
  					else
  					{
  						/* skip and consider next */
  						st->command++;
  					}
  
  					if (st->state != CSTATE_SKIP_COMMAND)
  						/* out of quick skip command loop */
  						break;
  				}
  				break;
  
  				/*
  				 * Wait for the current SQL command to complete
  				 */
  			case CSTATE_WAIT_RESULT:
  				if (debug)
  					fprintf(stderr, "client %d receiving\n", st->id);
  				if (!PQconsumeInput(st->con))
  				{
  					/* there's something wrong */
  					commandFailed(st, "SQL", "perhaps the backend died while processing");
  					st->state = CSTATE_ABORTED;
  					break;
  				}
  				if (PQisBusy(st->con))
  					return;		/* don't have the whole result yet */
  
  				/* store or discard the query results */
  				if (readCommandResponse(st, sql_script[st->use_file].commands[st->command]->varprefix))
  					st->state = CSTATE_END_COMMAND;
  				else
  					st->state = CSTATE_ABORTED;
  				break;
  
  				/*
  				 * Wait until sleep is done. This state is entered after a
  				 * \sleep metacommand. The behavior is similar to
  				 * CSTATE_THROTTLE, but proceeds to CSTATE_START_COMMAND
  				 * instead of CSTATE_START_TX.
  				 */
  			case CSTATE_SLEEP:
  				INSTR_TIME_SET_CURRENT_LAZY(now);
  				if (INSTR_TIME_GET_MICROSEC(now) < st->sleep_until)
  					return;		/* still sleeping, nothing to do here */
  				/* Else done sleeping. */
  				st->state = CSTATE_END_COMMAND;
  				break;
  
  				/*
  				 * End of command: record stats and proceed to next command.
  				 */
  			case CSTATE_END_COMMAND:
  
  				/*
  				 * command completed: accumulate per-command execution times
  				 * in thread-local data structure, if per-command latencies
  				 * are requested.
  				 */
  				if (report_per_command)
  				{
  					Command    *command;
  
  					INSTR_TIME_SET_CURRENT_LAZY(now);
  
  					command = sql_script[st->use_file].commands[st->command];
  					/* XXX could use a mutex here, but we choose not to */
  					addToSimpleStats(&command->stats,
  									 INSTR_TIME_GET_DOUBLE(now) -
  									 INSTR_TIME_GET_DOUBLE(st->stmt_begin));
  				}
  
  				/* Go ahead with next command, to be executed or skipped */
  				st->command++;
  				st->state = conditional_active(st->cstack) ?
  					CSTATE_START_COMMAND : CSTATE_SKIP_COMMAND;
  				break;
  
  				/*
  				 * End of transaction (end of script, really).
  				 */
  			case CSTATE_END_TX:
  
  				/* transaction finished: calculate latency and do log */
  				processXactStats(thread, st, &now, false, agg);
  
  				/*
  				 * missing \endif... cannot happen if CheckConditional was
  				 * okay
  				 */
  				Assert(conditional_stack_empty(st->cstack));
  
  				if (is_connect)
  				{
  					finishCon(st);
  					INSTR_TIME_SET_ZERO(now);
  				}
  
  				if ((st->cnt >= nxacts && duration <= 0) || timer_exceeded)
  				{
  					/* script completed */
  					st->state = CSTATE_FINISHED;
  					break;
  				}
  
  				/* next transaction (script) */
  				st->state = CSTATE_CHOOSE_SCRIPT;
  
  				/*
  				 * Ensure that we always return on this point, so as to avoid
  				 * an infinite loop if the script only contains meta commands.
  				 */
  				return;
  
  				/*
  				 * Final states.  Close the connection if it's still open.
  				 */
  			case CSTATE_ABORTED:
  			case CSTATE_FINISHED:
  				finishCon(st);
  				return;
  		}
  	}
  }
  
  /*
   * Subroutine for advanceConnectionState -- initiate or execute the current
   * meta command, and return the next state to set.
   *
   * *now is updated to the current time, unless the command is expected to
   * take no time to execute.
   */
  static ConnectionStateEnum
  executeMetaCommand(CState *st, instr_time *now)
  {
  	Command    *command = sql_script[st->use_file].commands[st->command];
  	int			argc;
  	char	  **argv;
  
  	Assert(command != NULL && command->type == META_COMMAND);
  
  	argc = command->argc;
  	argv = command->argv;
  
  	if (debug)
  	{
  		fprintf(stderr, "client %d executing \\%s", st->id, argv[0]);
  		for (int i = 1; i < argc; i++)
  			fprintf(stderr, " %s", argv[i]);
  		fprintf(stderr, "\n");
  	}
  
  	if (command->meta == META_SLEEP)
  	{
  		int			usec;
  
  		/*
  		 * A \sleep doesn't execute anything, we just get the delay from the
  		 * argument, and enter the CSTATE_SLEEP state.  (The per-command
  		 * latency will be recorded in CSTATE_SLEEP state, not here, after the
  		 * delay has elapsed.)
  		 */
  		if (!evaluateSleep(st, argc, argv, &usec))
  		{
  			commandFailed(st, "sleep", "execution of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  
  		INSTR_TIME_SET_CURRENT_LAZY(*now);
  		st->sleep_until = INSTR_TIME_GET_MICROSEC(*now) + usec;
  		return CSTATE_SLEEP;
  	}
  	else if (command->meta == META_SET)
  	{
  		PgBenchExpr *expr = command->expr;
  		PgBenchValue result;
  
  		if (!evaluateExpr(st, expr, &result))
  		{
  			commandFailed(st, argv[0], "evaluation of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  
  		if (!putVariableValue(st, argv[0], argv[1], &result))
  		{
  			commandFailed(st, "set", "assignment of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  	}
  	else if (command->meta == META_IF)
  	{
  		/* backslash commands with an expression to evaluate */
  		PgBenchExpr *expr = command->expr;
  		PgBenchValue result;
  		bool		cond;
  
  		if (!evaluateExpr(st, expr, &result))
  		{
  			commandFailed(st, argv[0], "evaluation of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  
  		cond = valueTruth(&result);
  		conditional_stack_push(st->cstack, cond ? IFSTATE_TRUE : IFSTATE_FALSE);
  	}
  	else if (command->meta == META_ELIF)
  	{
  		/* backslash commands with an expression to evaluate */
  		PgBenchExpr *expr = command->expr;
  		PgBenchValue result;
  		bool		cond;
  
  		if (conditional_stack_peek(st->cstack) == IFSTATE_TRUE)
  		{
  			/* elif after executed block, skip eval and wait for endif. */
  			conditional_stack_poke(st->cstack, IFSTATE_IGNORED);
  			return CSTATE_END_COMMAND;
  		}
  
  		if (!evaluateExpr(st, expr, &result))
  		{
  			commandFailed(st, argv[0], "evaluation of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  
  		cond = valueTruth(&result);
  		Assert(conditional_stack_peek(st->cstack) == IFSTATE_FALSE);
  		conditional_stack_poke(st->cstack, cond ? IFSTATE_TRUE : IFSTATE_FALSE);
  	}
  	else if (command->meta == META_ELSE)
  	{
  		switch (conditional_stack_peek(st->cstack))
  		{
  			case IFSTATE_TRUE:
  				conditional_stack_poke(st->cstack, IFSTATE_ELSE_FALSE);
  				break;
  			case IFSTATE_FALSE: /* inconsistent if active */
  			case IFSTATE_IGNORED:	/* inconsistent if active */
  			case IFSTATE_NONE:	/* else without if */
  			case IFSTATE_ELSE_TRUE: /* else after else */
  			case IFSTATE_ELSE_FALSE:	/* else after else */
  			default:
  				/* dead code if conditional check is ok */
  				Assert(false);
  		}
  	}
  	else if (command->meta == META_ENDIF)
  	{
  		Assert(!conditional_stack_empty(st->cstack));
  		conditional_stack_pop(st->cstack);
  	}
  	else if (command->meta == META_SETSHELL)
  	{
  		if (!runShellCommand(st, argv[1], argv + 2, argc - 2))
  		{
  			commandFailed(st, "setshell", "execution of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  	}
  	else if (command->meta == META_SHELL)
  	{
  		if (!runShellCommand(st, NULL, argv + 1, argc - 1))
  		{
  			commandFailed(st, "shell", "execution of meta-command failed");
  			return CSTATE_ABORTED;
  		}
  	}
  
  	/*
  	 * executing the expression or shell command might have taken a
  	 * non-negligible amount of time, so reset 'now'
  	 */
  	INSTR_TIME_SET_ZERO(*now);
  
  	return CSTATE_END_COMMAND;
  }
  
  /*
   * Print log entry after completing one transaction.
   *
   * We print Unix-epoch timestamps in the log, so that entries can be
   * correlated against other logs.  On some platforms this could be obtained
   * from the instr_time reading the caller has, but rather than get entangled
   * with that, we just eat the cost of an extra syscall in all cases.
   */
  static void
  doLog(TState *thread, CState *st,
  	  StatsData *agg, bool skipped, double latency, double lag)
  {
  	FILE	   *logfile = thread->logfile;
  
  	Assert(use_log);
  
  	/*
  	 * Skip the log entry if sampling is enabled and this row doesn't belong
  	 * to the random sample.
  	 */
  	if (sample_rate != 0.0 &&
  		pg_erand48(thread->ts_sample_rs.xseed) > sample_rate)
  		return;
  
  	/* should we aggregate the results or not? */
  	if (agg_interval > 0)
  	{
  		/*
  		 * Loop until we reach the interval of the current moment, and print
  		 * any empty intervals in between (this may happen with very low tps,
  		 * e.g. --rate=0.1).
  		 */
  		time_t		now = time(NULL);
  
  		while (agg->start_time + agg_interval <= now)
  		{
  			/* print aggregated report to logfile */
  			fprintf(logfile, "%ld " INT64_FORMAT " %.0f %.0f %.0f %.0f",
  					(long) agg->start_time,
  					agg->cnt,
  					agg->latency.sum,
  					agg->latency.sum2,
  					agg->latency.min,
  					agg->latency.max);
  			if (throttle_delay)
  			{
  				fprintf(logfile, " %.0f %.0f %.0f %.0f",
  						agg->lag.sum,
  						agg->lag.sum2,
  						agg->lag.min,
  						agg->lag.max);
  				if (latency_limit)
  					fprintf(logfile, " " INT64_FORMAT, agg->skipped);
  			}
  			fputc('\n', logfile);
  
  			/* reset data and move to next interval */
  			initStats(agg, agg->start_time + agg_interval);
  		}
  
  		/* accumulate the current transaction */
  		accumStats(agg, skipped, latency, lag);
  	}
  	else
  	{
  		/* no, print raw transactions */
  		struct timeval tv;
  
  		gettimeofday(&tv, NULL);
  		if (skipped)
  			fprintf(logfile, "%d " INT64_FORMAT " skipped %d %ld %ld",
  					st->id, st->cnt, st->use_file,
  					(long) tv.tv_sec, (long) tv.tv_usec);
  		else
  			fprintf(logfile, "%d " INT64_FORMAT " %.0f %d %ld %ld",
  					st->id, st->cnt, latency, st->use_file,
  					(long) tv.tv_sec, (long) tv.tv_usec);
  		if (throttle_delay)
  			fprintf(logfile, " %.0f", lag);
  		fputc('\n', logfile);
  	}
  }
  
  /*
   * Accumulate and report statistics at end of a transaction.
   *
   * (This is also called when a transaction is late and thus skipped.
   * Note that even skipped transactions are counted in the "cnt" fields.)
   */
  static void
  processXactStats(TState *thread, CState *st, instr_time *now,
  				 bool skipped, StatsData *agg)
  {
  	double		latency = 0.0,
  				lag = 0.0;
  	bool		thread_details = progress || throttle_delay || latency_limit,
  				detailed = thread_details || use_log || per_script_stats;
  
  	if (detailed && !skipped)
  	{
  		INSTR_TIME_SET_CURRENT_LAZY(*now);
  
  		/* compute latency & lag */
  		latency = INSTR_TIME_GET_MICROSEC(*now) - st->txn_scheduled;
  		lag = INSTR_TIME_GET_MICROSEC(st->txn_begin) - st->txn_scheduled;
  	}
  
  	if (thread_details)
  	{
  		/* keep detailed thread stats */
  		accumStats(&thread->stats, skipped, latency, lag);
  
  		/* count transactions over the latency limit, if needed */
  		if (latency_limit && latency > latency_limit)
  			thread->latency_late++;
  	}
  	else
  	{
  		/* no detailed stats, just count */
  		thread->stats.cnt++;
  	}
  
  	/* client stat is just counting */
  	st->cnt++;
  
  	if (use_log)
  		doLog(thread, st, agg, skipped, latency, lag);
  
  	/* XXX could use a mutex here, but we choose not to */
  	if (per_script_stats)
  		accumStats(&sql_script[st->use_file].stats, skipped, latency, lag);
  }
  
  
  /* discard connections */
  static void
  disconnect_all(CState *state, int length)
  {
  	int			i;
  
  	for (i = 0; i < length; i++)
  		finishCon(&state[i]);
  }
  
  /*
   * Remove old pgbench tables, if any exist
   */
  static void
  initDropTables(PGconn *con)
  {
  	fprintf(stderr, "dropping old tables...\n");
  
  	/*
  	 * We drop all the tables in one command, so that whether there are
  	 * foreign key dependencies or not doesn't matter.
  	 */
  	executeStatement(con, "drop table if exists "
  					 "pgbench_accounts, "
  					 "pgbench_branches, "
  					 "pgbench_history, "
  					 "pgbench_tellers");
  }
  
  /*
   * Create pgbench's standard tables
   */
  static void
  initCreateTables(PGconn *con)
  {
  	/*
  	 * Note: TPC-B requires at least 100 bytes per row, and the "filler"
  	 * fields in these table declarations were intended to comply with that.
  	 * The pgbench_accounts table complies with that because the "filler"
  	 * column is set to blank-padded empty string. But for all other tables
  	 * the columns default to NULL and so don't actually take any space.  We
  	 * could fix that by giving them non-null default values.  However, that
  	 * would completely break comparability of pgbench results with prior
  	 * versions. Since pgbench has never pretended to be fully TPC-B compliant
  	 * anyway, we stick with the historical behavior.
  	 */
  	struct ddlinfo
  	{
  		const char *table;		/* table name */
  		const char *smcols;		/* column decls if accountIDs are 32 bits */
  		const char *bigcols;	/* column decls if accountIDs are 64 bits */
  		int			declare_fillfactor;
  	};
  	static const struct ddlinfo DDLs[] = {
  		{
  			"pgbench_history",
  			"tid int,bid int,aid    int,delta int,mtime timestamp,filler char(22)",
  			"tid int,bid int,aid bigint,delta int,mtime timestamp,filler char(22)",
  			0
  		},
  		{
  			"pgbench_tellers",
  			"tid int not null,bid int,tbalance int,filler char(84)",
  			"tid int not null,bid int,tbalance int,filler char(84)",
  			1
  		},
  		{
  			"pgbench_accounts",
  			"aid    int not null,bid int,abalance int,filler char(84)",
  			"aid bigint not null,bid int,abalance int,filler char(84)",
  			1
  		},
  		{
  			"pgbench_branches",
  			"bid int not null,bbalance int,filler char(88)",
  			"bid int not null,bbalance int,filler char(88)",
  			1
  		}
  	};
  	int			i;
  
  	fprintf(stderr, "creating tables...\n");
  
  	for (i = 0; i < lengthof(DDLs); i++)
  	{
  		char		opts[256];
  		char		buffer[256];
  		const struct ddlinfo *ddl = &DDLs[i];
  		const char *cols;
  
  		/* Construct new create table statement. */
  		opts[0] = '\0';
  		if (ddl->declare_fillfactor)
  			snprintf(opts + strlen(opts), sizeof(opts) - strlen(opts),
  					 " with (fillfactor=%d)", fillfactor);
  		if (tablespace != NULL)
  		{
  			char	   *escape_tablespace;
  
  			escape_tablespace = PQescapeIdentifier(con, tablespace,
  												   strlen(tablespace));
  			snprintf(opts + strlen(opts), sizeof(opts) - strlen(opts),
  					 " tablespace %s", escape_tablespace);
  			PQfreemem(escape_tablespace);
  		}
  
  		cols = (scale >= SCALE_32BIT_THRESHOLD) ? ddl->bigcols : ddl->smcols;
  
  		snprintf(buffer, sizeof(buffer), "create%s table %s(%s)%s",
  				 unlogged_tables ? " unlogged" : "",
  				 ddl->table, cols, opts);
  
  		executeStatement(con, buffer);
  	}
  }
  
  /*
   * Fill the standard tables with some data
   */
  static void
  initGenerateData(PGconn *con)
  {
  	char		sql[256];
  	PGresult   *res;
  	int			i;
  	int64		k;
  
  	/* used to track elapsed time and estimate of the remaining time */
  	instr_time	start,
  				diff;
  	double		elapsed_sec,
  				remaining_sec;
  	int			log_interval = 1;
  
  	fprintf(stderr, "generating data...\n");
  
  	/*
  	 * we do all of this in one transaction to enable the backend's
  	 * data-loading optimizations
  	 */
  	executeStatement(con, "begin");
  
  	/*
  	 * truncate away any old data, in one command in case there are foreign
  	 * keys
  	 */
  	executeStatement(con, "truncate table "
  					 "pgbench_accounts, "
  					 "pgbench_branches, "
  					 "pgbench_history, "
  					 "pgbench_tellers");
  
  	/*
  	 * fill branches, tellers, accounts in that order in case foreign keys
  	 * already exist
  	 */
  	for (i = 0; i < nbranches * scale; i++)
  	{
  		/* "filler" column defaults to NULL */
  		snprintf(sql, sizeof(sql),
  				 "insert into pgbench_branches(bid,bbalance) values(%d,0)",
  				 i + 1);
  		executeStatement(con, sql);
  	}
  
  	for (i = 0; i < ntellers * scale; i++)
  	{
  		/* "filler" column defaults to NULL */
  		snprintf(sql, sizeof(sql),
  				 "insert into pgbench_tellers(tid,bid,tbalance) values (%d,%d,0)",
  				 i + 1, i / ntellers + 1);
  		executeStatement(con, sql);
  	}
  
  	/*
  	 * accounts is big enough to be worth using COPY and tracking runtime
  	 */
  	res = PQexec(con, "copy pgbench_accounts from stdin");
  	if (PQresultStatus(res) != PGRES_COPY_IN)
  	{
  		fprintf(stderr, "%s", PQerrorMessage(con));
  		exit(1);
  	}
  	PQclear(res);
  
  	INSTR_TIME_SET_CURRENT(start);
  
  	for (k = 0; k < (int64) naccounts * scale; k++)
  	{
  		int64		j = k + 1;
  
  		/* "filler" column defaults to blank padded empty string */
  		snprintf(sql, sizeof(sql),
  				 INT64_FORMAT "\t" INT64_FORMAT "\t%d\t\n",
  				 j, k / naccounts + 1, 0);
  		if (PQputline(con, sql))
  		{
  			fprintf(stderr, "PQputline failed\n");
  			exit(1);
  		}
  
  		/*
  		 * If we want to stick with the original logging, print a message each
  		 * 100k inserted rows.
  		 */
  		if ((!use_quiet) && (j % 100000 == 0))
  		{
  			INSTR_TIME_SET_CURRENT(diff);
  			INSTR_TIME_SUBTRACT(diff, start);
  
  			elapsed_sec = INSTR_TIME_GET_DOUBLE(diff);
  			remaining_sec = ((double) scale * naccounts - j) * elapsed_sec / j;
  
  			fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)\n",
  					j, (int64) naccounts * scale,
  					(int) (((int64) j * 100) / (naccounts * (int64) scale)),
  					elapsed_sec, remaining_sec);
  		}
  		/* let's not call the timing for each row, but only each 100 rows */
  		else if (use_quiet && (j % 100 == 0))
  		{
  			INSTR_TIME_SET_CURRENT(diff);
  			INSTR_TIME_SUBTRACT(diff, start);
  
  			elapsed_sec = INSTR_TIME_GET_DOUBLE(diff);
  			remaining_sec = ((double) scale * naccounts - j) * elapsed_sec / j;
  
  			/* have we reached the next interval (or end)? */
  			if ((j == scale * naccounts) || (elapsed_sec >= log_interval * LOG_STEP_SECONDS))
  			{
  				fprintf(stderr, INT64_FORMAT " of " INT64_FORMAT " tuples (%d%%) done (elapsed %.2f s, remaining %.2f s)\n",
  						j, (int64) naccounts * scale,
  						(int) (((int64) j * 100) / (naccounts * (int64) scale)), elapsed_sec, remaining_sec);
  
  				/* skip to the next interval */
  				log_interval = (int) ceil(elapsed_sec / LOG_STEP_SECONDS);
  			}
  		}
  
  	}
  	if (PQputline(con, "\\.\n"))
  	{
  		fprintf(stderr, "very last PQputline failed\n");
  		exit(1);
  	}
  	if (PQendcopy(con))
  	{
  		fprintf(stderr, "PQendcopy failed\n");
  		exit(1);
  	}
  
  	executeStatement(con, "commit");
  }
  
  /*
   * Invoke vacuum on the standard tables
   */
  static void
  initVacuum(PGconn *con)
  {
  	fprintf(stderr, "vacuuming...\n");
  	executeStatement(con, "vacuum analyze pgbench_branches");
  	executeStatement(con, "vacuum analyze pgbench_tellers");
  	executeStatement(con, "vacuum analyze pgbench_accounts");
  	executeStatement(con, "vacuum analyze pgbench_history");
  }
  
  /*
   * Create primary keys on the standard tables
   */
  static void
  initCreatePKeys(PGconn *con)
  {
  	static const char *const DDLINDEXes[] = {
  		"alter table pgbench_branches add primary key (bid)",
  		"alter table pgbench_tellers add primary key (tid)",
  		"alter table pgbench_accounts add primary key (aid)"
  	};
  	int			i;
  
  	fprintf(stderr, "creating primary keys...\n");
  	for (i = 0; i < lengthof(DDLINDEXes); i++)
  	{
  		char		buffer[256];
  
  		strlcpy(buffer, DDLINDEXes[i], sizeof(buffer));
  
  		if (index_tablespace != NULL)
  		{
  			char	   *escape_tablespace;
  
  			escape_tablespace = PQescapeIdentifier(con, index_tablespace,
  												   strlen(index_tablespace));
  			snprintf(buffer + strlen(buffer), sizeof(buffer) - strlen(buffer),
  					 " using index tablespace %s", escape_tablespace);
  			PQfreemem(escape_tablespace);
  		}
  
  		executeStatement(con, buffer);
  	}
  }
  
  /*
   * Create foreign key constraints between the standard tables
   */
  static void
  initCreateFKeys(PGconn *con)
  {
  	static const char *const DDLKEYs[] = {
  		"alter table pgbench_tellers add constraint pgbench_tellers_bid_fkey foreign key (bid) references pgbench_branches",
  		"alter table pgbench_accounts add constraint pgbench_accounts_bid_fkey foreign key (bid) references pgbench_branches",
  		"alter table pgbench_history add constraint pgbench_history_bid_fkey foreign key (bid) references pgbench_branches",
  		"alter table pgbench_history add constraint pgbench_history_tid_fkey foreign key (tid) references pgbench_tellers",
  		"alter table pgbench_history add constraint pgbench_history_aid_fkey foreign key (aid) references pgbench_accounts"
  	};
  	int			i;
  
  	fprintf(stderr, "creating foreign keys...\n");
  	for (i = 0; i < lengthof(DDLKEYs); i++)
  	{
  		executeStatement(con, DDLKEYs[i]);
  	}
  }
  
  /*
   * Validate an initialization-steps string
   *
   * (We could just leave it to runInitSteps() to fail if there are wrong
   * characters, but since initialization can take awhile, it seems friendlier
   * to check during option parsing.)
   */
  static void
  checkInitSteps(const char *initialize_steps)
  {
  	const char *step;
  
  	if (initialize_steps[0] == '\0')
  	{
  		fprintf(stderr, "no initialization steps specified\n");
  		exit(1);
  	}
  
  	for (step = initialize_steps; *step != '\0'; step++)
  	{
  		if (strchr("dtgvpf ", *step) == NULL)
  		{
  			fprintf(stderr, "unrecognized initialization step \"%c\"\n",
  					*step);
  			fprintf(stderr, "allowed steps are: \"d\", \"t\", \"g\", \"v\", \"p\", \"f\"\n");
  			exit(1);
  		}
  	}
  }
  
  /*
   * Invoke each initialization step in the given string
   */
  static void
  runInitSteps(const char *initialize_steps)
  {
  	PGconn	   *con;
  	const char *step;
  
  	if ((con = doConnect()) == NULL)
  		exit(1);
  
  	for (step = initialize_steps; *step != '\0'; step++)
  	{
  		switch (*step)
  		{
  			case 'd':
  				initDropTables(con);
  				break;
  			case 't':
  				initCreateTables(con);
  				break;
  			case 'g':
  				initGenerateData(con);
  				break;
  			case 'v':
  				initVacuum(con);
  				break;
  			case 'p':
  				initCreatePKeys(con);
  				break;
  			case 'f':
  				initCreateFKeys(con);
  				break;
  			case ' ':
  				break;			/* ignore */
  			default:
  				fprintf(stderr, "unrecognized initialization step \"%c\"\n",
  						*step);
  				PQfinish(con);
  				exit(1);
  		}
  	}
  
  	fprintf(stderr, "done.\n");
  	PQfinish(con);
  }
  
  /*
   * Replace :param with $n throughout the command's SQL text, which
   * is a modifiable string in cmd->lines.
   */
  static bool
  parseQuery(Command *cmd)
  {
  	char	   *sql,
  			   *p;
  
  	cmd->argc = 1;
  
  	p = sql = pg_strdup(cmd->lines.data);
  	while ((p = strchr(p, ':')) != NULL)
  	{
  		char		var[13];
  		char	   *name;
  		int			eaten;
  
  		name = parseVariable(p, &eaten);
  		if (name == NULL)
  		{
  			while (*p == ':')
  			{
  				p++;
  			}
  			continue;
  		}
  
  		/*
  		 * cmd->argv[0] is the SQL statement itself, so the max number of
  		 * arguments is one less than MAX_ARGS
  		 */
  		if (cmd->argc >= MAX_ARGS)
  		{
  			fprintf(stderr, "statement has too many arguments (maximum is %d): %s\n",
  					MAX_ARGS - 1, cmd->lines.data);
  			pg_free(name);
  			return false;
  		}
  
  		sprintf(var, "$%d", cmd->argc);
  		p = replaceVariable(&sql, p, eaten, var);
  
  		cmd->argv[cmd->argc] = name;
  		cmd->argc++;
  	}
  
  	Assert(cmd->argv[0] == NULL);
  	cmd->argv[0] = sql;
  	return true;
  }
  
  /*
   * syntax error while parsing a script (in practice, while parsing a
   * backslash command, because we don't detect syntax errors in SQL)
   *
   * source: source of script (filename or builtin-script ID)
   * lineno: line number within script (count from 1)
   * line: whole line of backslash command, if available
   * command: backslash command name, if available
   * msg: the actual error message
   * more: optional extra message
   * column: zero-based column number, or -1 if unknown
   */
  void
  syntax_error(const char *source, int lineno,
  			 const char *line, const char *command,
  			 const char *msg, const char *more, int column)
  {
  	fprintf(stderr, "%s:%d: %s", source, lineno, msg);
  	if (more != NULL)
  		fprintf(stderr, " (%s)", more);
  	if (column >= 0 && line == NULL)
  		fprintf(stderr, " at column %d", column + 1);
  	if (command != NULL)
  		fprintf(stderr, " in command \"%s\"", command);
  	fprintf(stderr, "\n");
  	if (line != NULL)
  	{
  		fprintf(stderr, "%s\n", line);
  		if (column >= 0)
  		{
  			int			i;
  
  			for (i = 0; i < column; i++)
  				fprintf(stderr, " ");
  			fprintf(stderr, "^ error found here\n");
  		}
  	}
  	exit(1);
  }
  
  /*
   * Return a pointer to the start of the SQL command, after skipping over
   * whitespace and "--" comments.
   * If the end of the string is reached, return NULL.
   */
  static char *
  skip_sql_comments(char *sql_command)
  {
  	char	   *p = sql_command;
  
  	/* Skip any leading whitespace, as well as "--" style comments */
  	for (;;)
  	{
  		if (isspace((unsigned char) *p))
  			p++;
  		else if (strncmp(p, "--", 2) == 0)
  		{
  			p = strchr(p, '\n');
  			if (p == NULL)
  				return NULL;
  			p++;
  		}
  		else
  			break;
  	}
  
  	/* NULL if there's nothing but whitespace and comments */
  	if (*p == '\0')
  		return NULL;
  
  	return p;
  }
  
  /*
   * Parse a SQL command; return a Command struct, or NULL if it's a comment
   *
   * On entry, psqlscan.l has collected the command into "buf", so we don't
   * really need to do much here except check for comments and set up a Command
   * struct.
   */
  static Command *
  create_sql_command(PQExpBuffer buf, const char *source)
  {
  	Command    *my_command;
  	char	   *p = skip_sql_comments(buf->data);
  
  	if (p == NULL)
  		return NULL;
  
  	/* Allocate and initialize Command structure */
  	my_command = (Command *) pg_malloc(sizeof(Command));
  	initPQExpBuffer(&my_command->lines);
  	appendPQExpBufferStr(&my_command->lines, p);
  	my_command->first_line = NULL;	/* this is set later */
  	my_command->type = SQL_COMMAND;
  	my_command->meta = META_NONE;
  	my_command->argc = 0;
  	memset(my_command->argv, 0, sizeof(my_command->argv));
  	my_command->varprefix = NULL;	/* allocated later, if needed */
  	my_command->expr = NULL;
  	initSimpleStats(&my_command->stats);
  
  	return my_command;
  }
  
  /* Free a Command structure and associated data */
  static void
  free_command(Command *command)
  {
  	termPQExpBuffer(&command->lines);
  	if (command->first_line)
  		pg_free(command->first_line);
  	for (int i = 0; i < command->argc; i++)
  		pg_free(command->argv[i]);
  	if (command->varprefix)
  		pg_free(command->varprefix);
  
  	/*
  	 * It should also free expr recursively, but this is currently not needed
  	 * as only gset commands (which do not have an expression) are freed.
  	 */
  	pg_free(command);
  }
  
  /*
   * Once an SQL command is fully parsed, possibly by accumulating several
   * parts, complete other fields of the Command structure.
   */
  static void
  postprocess_sql_command(Command *my_command)
  {
  	char		buffer[128];
  
  	Assert(my_command->type == SQL_COMMAND);
  
  	/* Save the first line for error display. */
  	strlcpy(buffer, my_command->lines.data, sizeof(buffer));
  	buffer[strcspn(buffer, "\n\r")] = '\0';
  	my_command->first_line = pg_strdup(buffer);
  
  	/* parse query if necessary */
  	switch (querymode)
  	{
  		case QUERY_SIMPLE:
  			my_command->argv[0] = my_command->lines.data;
  			my_command->argc++;
  			break;
  		case QUERY_EXTENDED:
  		case QUERY_PREPARED:
  			if (!parseQuery(my_command))
  				exit(1);
  			break;
  		default:
  			exit(1);
  	}
  }
  
  /*
   * Parse a backslash command; return a Command struct, or NULL if comment
   *
   * At call, we have scanned only the initial backslash.
   */
  static Command *
  process_backslash_command(PsqlScanState sstate, const char *source)
  {
  	Command    *my_command;
  	PQExpBufferData word_buf;
  	int			word_offset;
  	int			offsets[MAX_ARGS];	/* offsets of argument words */
  	int			start_offset;
  	int			lineno;
  	int			j;
  
  	initPQExpBuffer(&word_buf);
  
  	/* Remember location of the backslash */
  	start_offset = expr_scanner_offset(sstate) - 1;
  	lineno = expr_scanner_get_lineno(sstate, start_offset);
  
  	/* Collect first word of command */
  	if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
  	{
  		termPQExpBuffer(&word_buf);
  		return NULL;
  	}
  
  	/* Allocate and initialize Command structure */
  	my_command = (Command *) pg_malloc0(sizeof(Command));
  	my_command->type = META_COMMAND;
  	my_command->argc = 0;
  	initSimpleStats(&my_command->stats);
  
  	/* Save first word (command name) */
  	j = 0;
  	offsets[j] = word_offset;
  	my_command->argv[j++] = pg_strdup(word_buf.data);
  	my_command->argc++;
  
  	/* ... and convert it to enum form */
  	my_command->meta = getMetaCommand(my_command->argv[0]);
  
  	if (my_command->meta == META_SET ||
  		my_command->meta == META_IF ||
  		my_command->meta == META_ELIF)
  	{
  		yyscan_t	yyscanner;
  
  		/* For \set, collect var name */
  		if (my_command->meta == META_SET)
  		{
  			if (!expr_lex_one_word(sstate, &word_buf, &word_offset))
  				syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  							 "missing argument", NULL, -1);
  
  			offsets[j] = word_offset;
  			my_command->argv[j++] = pg_strdup(word_buf.data);
  			my_command->argc++;
  		}
  
  		/* then for all parse the expression */
  		yyscanner = expr_scanner_init(sstate, source, lineno, start_offset,
  									  my_command->argv[0]);
  
  		if (expr_yyparse(yyscanner) != 0)
  		{
  			/* dead code: exit done from syntax_error called by yyerror */
  			exit(1);
  		}
  
  		my_command->expr = expr_parse_result;
  
  		/* Save line, trimming any trailing newline */
  		my_command->first_line =
  			expr_scanner_get_substring(sstate,
  									   start_offset,
  									   expr_scanner_offset(sstate),
  									   true);
  
  		expr_scanner_finish(yyscanner);
  
  		termPQExpBuffer(&word_buf);
  
  		return my_command;
  	}
  
  	/* For all other commands, collect remaining words. */
  	while (expr_lex_one_word(sstate, &word_buf, &word_offset))
  	{
  		/*
  		 * my_command->argv[0] is the command itself, so the max number of
  		 * arguments is one less than MAX_ARGS
  		 */
  		if (j >= MAX_ARGS)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "too many arguments", NULL, -1);
  
  		offsets[j] = word_offset;
  		my_command->argv[j++] = pg_strdup(word_buf.data);
  		my_command->argc++;
  	}
  
  	/* Save line, trimming any trailing newline */
  	my_command->first_line =
  		expr_scanner_get_substring(sstate,
  								   start_offset,
  								   expr_scanner_offset(sstate),
  								   true);
  
  	if (my_command->meta == META_SLEEP)
  	{
  		if (my_command->argc < 2)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "missing argument", NULL, -1);
  
  		if (my_command->argc > 3)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "too many arguments", NULL,
  						 offsets[3] - start_offset);
  
  		/*
  		 * Split argument into number and unit to allow "sleep 1ms" etc. We
  		 * don't have to terminate the number argument with null because it
  		 * will be parsed with atoi, which ignores trailing non-digit
  		 * characters.
  		 */
  		if (my_command->argc == 2 && my_command->argv[1][0] != ':')
  		{
  			char	   *c = my_command->argv[1];
  
  			while (isdigit((unsigned char) *c))
  				c++;
  			if (*c)
  			{
  				my_command->argv[2] = c;
  				offsets[2] = offsets[1] + (c - my_command->argv[1]);
  				my_command->argc = 3;
  			}
  		}
  
  		if (my_command->argc == 3)
  		{
  			if (pg_strcasecmp(my_command->argv[2], "us") != 0 &&
  				pg_strcasecmp(my_command->argv[2], "ms") != 0 &&
  				pg_strcasecmp(my_command->argv[2], "s") != 0)
  				syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  							 "unrecognized time unit, must be us, ms or s",
  							 my_command->argv[2], offsets[2] - start_offset);
  		}
  	}
  	else if (my_command->meta == META_SETSHELL)
  	{
  		if (my_command->argc < 3)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "missing argument", NULL, -1);
  	}
  	else if (my_command->meta == META_SHELL)
  	{
  		if (my_command->argc < 2)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "missing command", NULL, -1);
  	}
  	else if (my_command->meta == META_ELSE || my_command->meta == META_ENDIF)
  	{
  		if (my_command->argc != 1)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "unexpected argument", NULL, -1);
  	}
  	else if (my_command->meta == META_GSET)
  	{
  		if (my_command->argc > 2)
  			syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  						 "too many arguments", NULL, -1);
  	}
  	else
  	{
  		/* my_command->meta == META_NONE */
  		syntax_error(source, lineno, my_command->first_line, my_command->argv[0],
  					 "invalid command", NULL, -1);
  	}
  
  	termPQExpBuffer(&word_buf);
  
  	return my_command;
  }
  
  static void
  ConditionError(const char *desc, int cmdn, const char *msg)
  {
  	fprintf(stderr,
  			"condition error in script \"%s\" command %d: %s\n",
  			desc, cmdn, msg);
  	exit(1);
  }
  
  /*
   * Partial evaluation of conditionals before recording and running the script.
   */
  static void
  CheckConditional(ParsedScript ps)
  {
  	/* statically check conditional structure */
  	ConditionalStack cs = conditional_stack_create();
  	int			i;
  
  	for (i = 0; ps.commands[i] != NULL; i++)
  	{
  		Command    *cmd = ps.commands[i];
  
  		if (cmd->type == META_COMMAND)
  		{
  			switch (cmd->meta)
  			{
  				case META_IF:
  					conditional_stack_push(cs, IFSTATE_FALSE);
  					break;
  				case META_ELIF:
  					if (conditional_stack_empty(cs))
  						ConditionError(ps.desc, i + 1, "\\elif without matching \\if");
  					if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
  						ConditionError(ps.desc, i + 1, "\\elif after \\else");
  					break;
  				case META_ELSE:
  					if (conditional_stack_empty(cs))
  						ConditionError(ps.desc, i + 1, "\\else without matching \\if");
  					if (conditional_stack_peek(cs) == IFSTATE_ELSE_FALSE)
  						ConditionError(ps.desc, i + 1, "\\else after \\else");
  					conditional_stack_poke(cs, IFSTATE_ELSE_FALSE);
  					break;
  				case META_ENDIF:
  					if (!conditional_stack_pop(cs))
  						ConditionError(ps.desc, i + 1, "\\endif without matching \\if");
  					break;
  				default:
  					/* ignore anything else... */
  					break;
  			}
  		}
  	}
  	if (!conditional_stack_empty(cs))
  		ConditionError(ps.desc, i + 1, "\\if without matching \\endif");
  	conditional_stack_destroy(cs);
  }
  
  /*
   * Parse a script (either the contents of a file, or a built-in script)
   * and add it to the list of scripts.
   */
  static void
  ParseScript(const char *script, const char *desc, int weight)
  {
  	ParsedScript ps;
  	PsqlScanState sstate;
  	PQExpBufferData line_buf;
  	int			alloc_num;
  	int			index;
  	int			lineno;
  	int			start_offset;
  
  #define COMMANDS_ALLOC_NUM 128
  	alloc_num = COMMANDS_ALLOC_NUM;
  
  	/* Initialize all fields of ps */
  	ps.desc = desc;
  	ps.weight = weight;
  	ps.commands = (Command **) pg_malloc(sizeof(Command *) * alloc_num);
  	initStats(&ps.stats, 0);
  
  	/* Prepare to parse script */
  	sstate = psql_scan_create(&pgbench_callbacks);
  
  	/*
  	 * Ideally, we'd scan scripts using the encoding and stdstrings settings
  	 * we get from a DB connection.  However, without major rearrangement of
  	 * pgbench's argument parsing, we can't have a DB connection at the time
  	 * we parse scripts.  Using SQL_ASCII (encoding 0) should work well enough
  	 * with any backend-safe encoding, though conceivably we could be fooled
  	 * if a script file uses a client-only encoding.  We also assume that
  	 * stdstrings should be true, which is a bit riskier.
  	 */
  	psql_scan_setup(sstate, script, strlen(script), 0, true);
  	start_offset = expr_scanner_offset(sstate) - 1;
  
  	initPQExpBuffer(&line_buf);
  
  	index = 0;
  
  	for (;;)
  	{
  		PsqlScanResult sr;
  		promptStatus_t prompt;
  		Command    *command = NULL;
  
  		resetPQExpBuffer(&line_buf);
  		lineno = expr_scanner_get_lineno(sstate, start_offset);
  
  		sr = psql_scan(sstate, &line_buf, &prompt);
  
  		/* If we collected a new SQL command, process that */
  		command = create_sql_command(&line_buf, desc);
  
  		/* store new command */
  		if (command)
  			ps.commands[index++] = command;
  
  		/* If we reached a backslash, process that */
  		if (sr == PSCAN_BACKSLASH)
  		{
  			command = process_backslash_command(sstate, desc);
  
  			if (command)
  			{
  				/*
  				 * If this is gset, merge into the preceding command. (We
  				 * don't use a command slot in this case).
  				 */
  				if (command->meta == META_GSET)
  				{
  					Command    *cmd;
  
  					if (index == 0)
  						syntax_error(desc, lineno, NULL, NULL,
  									 "\\gset must follow a SQL command",
  									 NULL, -1);
  
  					cmd = ps.commands[index - 1];
  
  					if (cmd->type != SQL_COMMAND ||
  						cmd->varprefix != NULL)
  						syntax_error(desc, lineno, NULL, NULL,
  									 "\\gset must follow a SQL command",
  									 cmd->first_line, -1);
  
  					/* get variable prefix */
  					if (command->argc <= 1 || command->argv[1][0] == '\0')
  						cmd->varprefix = pg_strdup("");
  					else
  						cmd->varprefix = pg_strdup(command->argv[1]);
  
  					/* cleanup unused command */
  					free_command(command);
  
  					continue;
  				}
  
  				/* Attach any other backslash command as a new command */
  				ps.commands[index++] = command;
  			}
  		}
  
  		/*
  		 * Since we used a command slot, allocate more if needed.  Note we
  		 * always allocate one more in order to accommodate the NULL
  		 * terminator below.
  		 */
  		if (index >= alloc_num)
  		{
  			alloc_num += COMMANDS_ALLOC_NUM;
  			ps.commands = (Command **)
  				pg_realloc(ps.commands, sizeof(Command *) * alloc_num);
  		}
  
  		/* Done if we reached EOF */
  		if (sr == PSCAN_INCOMPLETE || sr == PSCAN_EOL)
  			break;
  	}
  
  	ps.commands[index] = NULL;
  
  	addScript(ps);
  
  	termPQExpBuffer(&line_buf);
  	psql_scan_finish(sstate);
  	psql_scan_destroy(sstate);
  }
  
  /*
   * Read the entire contents of file fd, and return it in a malloc'd buffer.
   *
   * The buffer will typically be larger than necessary, but we don't care
   * in this program, because we'll free it as soon as we've parsed the script.
   */
  static char *
  read_file_contents(FILE *fd)
  {
  	char	   *buf;
  	size_t		buflen = BUFSIZ;
  	size_t		used = 0;
  
  	buf = (char *) pg_malloc(buflen);
  
  	for (;;)
  	{
  		size_t		nread;
  
  		nread = fread(buf + used, 1, BUFSIZ, fd);
  		used += nread;
  		/* If fread() read less than requested, must be EOF or error */
  		if (nread < BUFSIZ)
  			break;
  		/* Enlarge buf so we can read some more */
  		buflen += BUFSIZ;
  		buf = (char *) pg_realloc(buf, buflen);
  	}
  	/* There is surely room for a terminator */
  	buf[used] = '\0';
  
  	return buf;
  }
  
  /*
   * Given a file name, read it and add its script to the list.
   * "-" means to read stdin.
   * NB: filename must be storage that won't disappear.
   */
  static void
  process_file(const char *filename, int weight)
  {
  	FILE	   *fd;
  	char	   *buf;
  
  	/* Slurp the file contents into "buf" */
  	if (strcmp(filename, "-") == 0)
  		fd = stdin;
  	else if ((fd = fopen(filename, "r")) == NULL)
  	{
  		fprintf(stderr, "could not open file \"%s\": %s\n",
  				filename, strerror(errno));
  		exit(1);
  	}
  
  	buf = read_file_contents(fd);
  
  	if (ferror(fd))
  	{
  		fprintf(stderr, "could not read file \"%s\": %s\n",
  				filename, strerror(errno));
  		exit(1);
  	}
  
  	if (fd != stdin)
  		fclose(fd);
  
  	ParseScript(buf, filename, weight);
  
  	free(buf);
  }
  
  /* Parse the given builtin script and add it to the list. */
  static void
  process_builtin(const BuiltinScript *bi, int weight)
  {
  	ParseScript(bi->script, bi->desc, weight);
  }
  
  /* show available builtin scripts */
  static void
  listAvailableScripts(void)
  {
  	int			i;
  
  	fprintf(stderr, "Available builtin scripts:\n");
  	for (i = 0; i < lengthof(builtin_script); i++)
  		fprintf(stderr, "\t%s\n", builtin_script[i].name);
  	fprintf(stderr, "\n");
  }
  
  /* return builtin script "name" if unambiguous, fails if not found */
  static const BuiltinScript *
  findBuiltin(const char *name)
  {
  	int			i,
  				found = 0,
  				len = strlen(name);
  	const BuiltinScript *result = NULL;
  
  	for (i = 0; i < lengthof(builtin_script); i++)
  	{
  		if (strncmp(builtin_script[i].name, name, len) == 0)
  		{
  			result = &builtin_script[i];
  			found++;
  		}
  	}
  
  	/* ok, unambiguous result */
  	if (found == 1)
  		return result;
  
  	/* error cases */
  	if (found == 0)
  		fprintf(stderr, "no builtin script found for name \"%s\"\n", name);
  	else						/* found > 1 */
  		fprintf(stderr,
  				"ambiguous builtin name: %d builtin scripts found for prefix \"%s\"\n", found, name);
  
  	listAvailableScripts();
  	exit(1);
  }
  
  /*
   * Determine the weight specification from a script option (-b, -f), if any,
   * and return it as an integer (1 is returned if there's no weight).  The
   * script name is returned in *script as a malloc'd string.
   */
  static int
  parseScriptWeight(const char *option, char **script)
  {
  	char	   *sep;
  	int			weight;
  
  	if ((sep = strrchr(option, WSEP)))
  	{
  		int			namelen = sep - option;
  		long		wtmp;
  		char	   *badp;
  
  		/* generate the script name */
  		*script = pg_malloc(namelen + 1);
  		strncpy(*script, option, namelen);
  		(*script)[namelen] = '\0';
  
  		/* process digits of the weight spec */
  		errno = 0;
  		wtmp = strtol(sep + 1, &badp, 10);
  		if (errno != 0 || badp == sep + 1 || *badp != '\0')
  		{
  			fprintf(stderr, "invalid weight specification: %s\n", sep);
  			exit(1);
  		}
  		if (wtmp > INT_MAX || wtmp < 0)
  		{
  			fprintf(stderr,
  					"weight specification out of range (0 .. %u): " INT64_FORMAT "\n",
  					INT_MAX, (int64) wtmp);
  			exit(1);
  		}
  		weight = wtmp;
  	}
  	else
  	{
  		*script = pg_strdup(option);
  		weight = 1;
  	}
  
  	return weight;
  }
  
  /* append a script to the list of scripts to process */
  static void
  addScript(ParsedScript script)
  {
  	if (script.commands == NULL || script.commands[0] == NULL)
  	{
  		fprintf(stderr, "empty command list for script \"%s\"\n", script.desc);
  		exit(1);
  	}
  
  	if (num_scripts >= MAX_SCRIPTS)
  	{
  		fprintf(stderr, "at most %d SQL scripts are allowed\n", MAX_SCRIPTS);
  		exit(1);
  	}
  
  	CheckConditional(script);
  
  	sql_script[num_scripts] = script;
  	num_scripts++;
  }
  
  /*
   * Print progress report.
   *
   * On entry, *last and *last_report contain the statistics and time of last
   * progress report.  On exit, they are updated with the new stats.
   */
  static void
  printProgressReport(TState *threads, int64 test_start, int64 now,
  					StatsData *last, int64 *last_report)
  {
  	/* generate and show report */
  	int64		run = now - *last_report,
  				ntx;
  	double		tps,
  				total_run,
  				latency,
  				sqlat,
  				lag,
  				stdev;
  	char		tbuf[315];
  	StatsData	cur;
  
  	/*
  	 * Add up the statistics of all threads.
  	 *
  	 * XXX: No locking.  There is no guarantee that we get an atomic snapshot
  	 * of the transaction count and latencies, so these figures can well be
  	 * off by a small amount.  The progress report's purpose is to give a
  	 * quick overview of how the test is going, so that shouldn't matter too
  	 * much.  (If a read from a 64-bit integer is not atomic, you might get a
  	 * "torn" read and completely bogus latencies though!)
  	 */
  	initStats(&cur, 0);
  	for (int i = 0; i < nthreads; i++)
  	{
  		mergeSimpleStats(&cur.latency, &threads[i].stats.latency);
  		mergeSimpleStats(&cur.lag, &threads[i].stats.lag);
  		cur.cnt += threads[i].stats.cnt;
  		cur.skipped += threads[i].stats.skipped;
  	}
  
  	/* we count only actually executed transactions */
  	ntx = (cur.cnt - cur.skipped) - (last->cnt - last->skipped);
  	total_run = (now - test_start) / 1000000.0;
  	tps = 1000000.0 * ntx / run;
  	if (ntx > 0)
  	{
  		latency = 0.001 * (cur.latency.sum - last->latency.sum) / ntx;
  		sqlat = 1.0 * (cur.latency.sum2 - last->latency.sum2) / ntx;
  		stdev = 0.001 * sqrt(sqlat - 1000000.0 * latency * latency);
  		lag = 0.001 * (cur.lag.sum - last->lag.sum) / ntx;
  	}
  	else
  	{
  		latency = sqlat = stdev = lag = 0;
  	}
  
  	if (progress_timestamp)
  	{
  		/*
  		 * On some platforms the current system timestamp is available in
  		 * now_time, but rather than get entangled with that, we just eat the
  		 * cost of an extra syscall in all cases.
  		 */
  		struct timeval tv;
  
  		gettimeofday(&tv, NULL);
  		snprintf(tbuf, sizeof(tbuf), "%ld.%03ld s",
  				 (long) tv.tv_sec, (long) (tv.tv_usec / 1000));
  	}
  	else
  	{
  		/* round seconds are expected, but the thread may be late */
  		snprintf(tbuf, sizeof(tbuf), "%.1f s", total_run);
  	}
  
  	fprintf(stderr,
  			"progress: %s, %.1f tps, lat %.3f ms stddev %.3f",
  			tbuf, tps, latency, stdev);
  
  	if (throttle_delay)
  	{
  		fprintf(stderr, ", lag %.3f ms", lag);
  		if (latency_limit)
  			fprintf(stderr, ", " INT64_FORMAT " skipped",
  					cur.skipped - last->skipped);
  	}
  	fprintf(stderr, "\n");
  
  	*last = cur;
  	*last_report = now;
  }
  
  static void
  printSimpleStats(const char *prefix, SimpleStats *ss)
  {
  	if (ss->count > 0)
  	{
  		double		latency = ss->sum / ss->count;
  		double		stddev = sqrt(ss->sum2 / ss->count - latency * latency);
  
  		printf("%s average = %.3f ms\n", prefix, 0.001 * latency);
  		printf("%s stddev = %.3f ms\n", prefix, 0.001 * stddev);
  	}
  }
  
  /* print out results */
  static void
  printResults(StatsData *total, instr_time total_time,
  			 instr_time conn_total_time, int64 latency_late)
  {
  	double		time_include,
  				tps_include,
  				tps_exclude;
  	int64		ntx = total->cnt - total->skipped;
  
  	time_include = INSTR_TIME_GET_DOUBLE(total_time);
  
  	/* tps is about actually executed transactions */
  	tps_include = ntx / time_include;
  	tps_exclude = ntx /
  		(time_include - (INSTR_TIME_GET_DOUBLE(conn_total_time) / nclients));
  
  	/* Report test parameters. */
  	printf("transaction type: %s\n",
  		   num_scripts == 1 ? sql_script[0].desc : "multiple scripts");
  	printf("scaling factor: %d\n", scale);
  	printf("query mode: %s\n", QUERYMODE[querymode]);
  	printf("number of clients: %d\n", nclients);
  	printf("number of threads: %d\n", nthreads);
  	if (duration <= 0)
  	{
  		printf("number of transactions per client: %d\n", nxacts);
  		printf("number of transactions actually processed: " INT64_FORMAT "/%d\n",
  			   ntx, nxacts * nclients);
  	}
  	else
  	{
  		printf("duration: %d s\n", duration);
  		printf("number of transactions actually processed: " INT64_FORMAT "\n",
  			   ntx);
  	}
  
  	/* Remaining stats are nonsensical if we failed to execute any xacts */
  	if (total->cnt <= 0)
  		return;
  
  	if (throttle_delay && latency_limit)
  		printf("number of transactions skipped: " INT64_FORMAT " (%.3f %%)\n",
  			   total->skipped,
  			   100.0 * total->skipped / total->cnt);
  
  	if (latency_limit)
  		printf("number of transactions above the %.1f ms latency limit: " INT64_FORMAT "/" INT64_FORMAT " (%.3f %%)\n",
  			   latency_limit / 1000.0, latency_late, ntx,
  			   (ntx > 0) ? 100.0 * latency_late / ntx : 0.0);
  
  	if (throttle_delay || progress || latency_limit)
  		printSimpleStats("latency", &total->latency);
  	else
  	{
  		/* no measurement, show average latency computed from run time */
  		printf("latency average = %.3f ms\n",
  			   1000.0 * time_include * nclients / total->cnt);
  	}
  
  	if (throttle_delay)
  	{
  		/*
  		 * Report average transaction lag under rate limit throttling.  This
  		 * is the delay between scheduled and actual start times for the
  		 * transaction.  The measured lag may be caused by thread/client load,
  		 * the database load, or the Poisson throttling process.
  		 */
  		printf("rate limit schedule lag: avg %.3f (max %.3f) ms\n",
  			   0.001 * total->lag.sum / total->cnt, 0.001 * total->lag.max);
  	}
  
  	printf("tps = %f (including connections establishing)\n", tps_include);
  	printf("tps = %f (excluding connections establishing)\n", tps_exclude);
  
  	/* Report per-script/command statistics */
  	if (per_script_stats || report_per_command)
  	{
  		int			i;
  
  		for (i = 0; i < num_scripts; i++)
  		{
  			if (per_script_stats)
  			{
  				StatsData  *sstats = &sql_script[i].stats;
  
  				printf("SQL script %d: %s\n"
  					   " - weight: %d (targets %.1f%% of total)\n"
  					   " - " INT64_FORMAT " transactions (%.1f%% of total, tps = %f)\n",
  					   i + 1, sql_script[i].desc,
  					   sql_script[i].weight,
  					   100.0 * sql_script[i].weight / total_weight,
  					   sstats->cnt,
  					   100.0 * sstats->cnt / total->cnt,
  					   (sstats->cnt - sstats->skipped) / time_include);
  
  				if (throttle_delay && latency_limit && sstats->cnt > 0)
  					printf(" - number of transactions skipped: " INT64_FORMAT " (%.3f%%)\n",
  						   sstats->skipped,
  						   100.0 * sstats->skipped / sstats->cnt);
  
  				printSimpleStats(" - latency", &sstats->latency);
  			}
  
  			/* Report per-command latencies */
  			if (report_per_command)
  			{
  				Command   **commands;
  
  				if (per_script_stats)
  					printf(" - statement latencies in milliseconds:\n");
  				else
  					printf("statement latencies in milliseconds:\n");
  
  				for (commands = sql_script[i].commands;
  					 *commands != NULL;
  					 commands++)
  				{
  					SimpleStats *cstats = &(*commands)->stats;
  
  					printf("   %11.3f  %s\n",
  						   (cstats->count > 0) ?
  						   1000.0 * cstats->sum / cstats->count : 0.0,
  						   (*commands)->first_line);
  				}
  			}
  		}
  	}
  }
  
  /*
   * Set up a random seed according to seed parameter (NULL means default),
   * and initialize base_random_sequence for use in initializing other sequences.
   */
  static bool
  set_random_seed(const char *seed)
  {
  	uint64		iseed;
  
  	if (seed == NULL || strcmp(seed, "time") == 0)
  	{
  		/* rely on current time */
  		instr_time	now;
  
  		INSTR_TIME_SET_CURRENT(now);
  		iseed = (uint64) INSTR_TIME_GET_MICROSEC(now);
  	}
  	else if (strcmp(seed, "rand") == 0)
  	{
  		/* use some "strong" random source */
  		if (!pg_strong_random(&iseed, sizeof(iseed)))
  		{
  			fprintf(stderr, "could not generate random seed.\n");
  			return false;
  		}
  	}
  	else
  	{
  		/* parse unsigned-int seed value */
  		unsigned long ulseed;
  		char		garbage;
  
  		/* Don't try to use UINT64_FORMAT here; it might not work for sscanf */
  		if (sscanf(seed, "%lu%c", &ulseed, &garbage) != 1)
  		{
  			fprintf(stderr,
  					"unrecognized random seed option \"%s\": expecting an unsigned integer, \"time\" or \"rand\"\n",
  					seed);
  			return false;
  		}
  		iseed = (uint64) ulseed;
  	}
  
  	if (seed != NULL)
  		fprintf(stderr, "setting random seed to " UINT64_FORMAT "\n", iseed);
  	random_seed = iseed;
  
  	/* Fill base_random_sequence with low-order bits of seed */
  	base_random_sequence.xseed[0] = iseed & 0xFFFF;
  	base_random_sequence.xseed[1] = (iseed >> 16) & 0xFFFF;
  	base_random_sequence.xseed[2] = (iseed >> 32) & 0xFFFF;
  
  	return true;
  }
  
  int
  main(int argc, char **argv)
  {
  	static struct option long_options[] = {
  		/* systematic long/short named options */
  		{"builtin", required_argument, NULL, 'b'},
  		{"client", required_argument, NULL, 'c'},
  		{"connect", no_argument, NULL, 'C'},
  		{"debug", no_argument, NULL, 'd'},
  		{"define", required_argument, NULL, 'D'},
  		{"file", required_argument, NULL, 'f'},
  		{"fillfactor", required_argument, NULL, 'F'},
  		{"host", required_argument, NULL, 'h'},
  		{"initialize", no_argument, NULL, 'i'},
  		{"init-steps", required_argument, NULL, 'I'},
  		{"jobs", required_argument, NULL, 'j'},
  		{"log", no_argument, NULL, 'l'},
  		{"latency-limit", required_argument, NULL, 'L'},
  		{"no-vacuum", no_argument, NULL, 'n'},
  		{"port", required_argument, NULL, 'p'},
  		{"progress", required_argument, NULL, 'P'},
  		{"protocol", required_argument, NULL, 'M'},
  		{"quiet", no_argument, NULL, 'q'},
  		{"report-latencies", no_argument, NULL, 'r'},
  		{"rate", required_argument, NULL, 'R'},
  		{"scale", required_argument, NULL, 's'},
  		{"select-only", no_argument, NULL, 'S'},
  		{"skip-some-updates", no_argument, NULL, 'N'},
  		{"time", required_argument, NULL, 'T'},
  		{"transactions", required_argument, NULL, 't'},
  		{"username", required_argument, NULL, 'U'},
  		{"vacuum-all", no_argument, NULL, 'v'},
  		/* long-named only options */
  		{"unlogged-tables", no_argument, NULL, 1},
  		{"tablespace", required_argument, NULL, 2},
  		{"index-tablespace", required_argument, NULL, 3},
  		{"sampling-rate", required_argument, NULL, 4},
  		{"aggregate-interval", required_argument, NULL, 5},
  		{"progress-timestamp", no_argument, NULL, 6},
  		{"log-prefix", required_argument, NULL, 7},
  		{"foreign-keys", no_argument, NULL, 8},
  		{"random-seed", required_argument, NULL, 9},
  		{NULL, 0, NULL, 0}
  	};
  
  	int			c;
  	bool		is_init_mode = false;	/* initialize mode? */
  	char	   *initialize_steps = NULL;
  	bool		foreign_keys = false;
  	bool		is_no_vacuum = false;
  	bool		do_vacuum_accounts = false; /* vacuum accounts table? */
  	int			optindex;
  	bool		scale_given = false;
  
  	bool		benchmarking_option_set = false;
  	bool		initialization_option_set = false;
  	bool		internal_script_used = false;
  
  	CState	   *state;			/* status of clients */
  	TState	   *threads;		/* array of thread */
  
  	instr_time	start_time;		/* start up time */
  	instr_time	total_time;
  	instr_time	conn_total_time;
  	int64		latency_late = 0;
  	StatsData	stats;
  	int			weight;
  
  	int			i;
  	int			nclients_dealt;
  
  #ifdef HAVE_GETRLIMIT
  	struct rlimit rlim;
  #endif
  
  	PGconn	   *con;
  	PGresult   *res;
  	char	   *env;
  
  	int			exit_code = 0;
  
  	pg_logging_init(argv[0]);
  	progname = get_progname(argv[0]);
  
  	if (argc > 1)
  	{
  		if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
  		{
  			usage();
  			exit(0);
  		}
  		if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
  		{
  			puts("pgbench (PostgreSQL) " PG_VERSION);
  			exit(0);
  		}
  	}
  
  	if ((env = getenv("PGHOST")) != NULL && *env != '\0')
  		pghost = env;
  	if ((env = getenv("PGPORT")) != NULL && *env != '\0')
  		pgport = env;
  	else if ((env = getenv("PGUSER")) != NULL && *env != '\0')
  		login = env;
  
  	state = (CState *) pg_malloc0(sizeof(CState));
  
  	/* set random seed early, because it may be used while parsing scripts. */
  	if (!set_random_seed(getenv("PGBENCH_RANDOM_SEED")))
  	{
  		fprintf(stderr, "error while setting random seed from PGBENCH_RANDOM_SEED environment variable\n");
  		exit(1);
  	}
  
  	while ((c = getopt_long(argc, argv, "iI:h:nvp:dqb:SNc:j:Crs:t:T:U:lf:D:F:M:P:R:L:", long_options, &optindex)) != -1)
  	{
  		char	   *script;
  
  		switch (c)
  		{
  			case 'i':
  				is_init_mode = true;
  				break;
  			case 'I':
  				if (initialize_steps)
  					pg_free(initialize_steps);
  				initialize_steps = pg_strdup(optarg);
  				checkInitSteps(initialize_steps);
  				initialization_option_set = true;
  				break;
  			case 'h':
  				pghost = pg_strdup(optarg);
  				break;
  			case 'n':
  				is_no_vacuum = true;
  				break;
  			case 'v':
  				benchmarking_option_set = true;
  				do_vacuum_accounts = true;
  				break;
  			case 'p':
  				pgport = pg_strdup(optarg);
  				break;
  			case 'd':
  				debug++;
  				break;
  			case 'c':
  				benchmarking_option_set = true;
  				nclients = atoi(optarg);
  				if (nclients <= 0)
  				{
  					fprintf(stderr, "invalid number of clients: \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  #ifdef HAVE_GETRLIMIT
  #ifdef RLIMIT_NOFILE			/* most platforms use RLIMIT_NOFILE */
  				if (getrlimit(RLIMIT_NOFILE, &rlim) == -1)
  #else							/* but BSD doesn't ... */
  				if (getrlimit(RLIMIT_OFILE, &rlim) == -1)
  #endif							/* RLIMIT_NOFILE */
  				{
  					fprintf(stderr, "getrlimit failed: %s\n", strerror(errno));
  					exit(1);
  				}
  				if (rlim.rlim_cur < nclients + 3)
  				{
  					fprintf(stderr, "need at least %d open files, but system limit is %ld\n",
  							nclients + 3, (long) rlim.rlim_cur);
  					fprintf(stderr, "Reduce number of clients, or use limit/ulimit to increase the system limit.\n");
  					exit(1);
  				}
  #endif							/* HAVE_GETRLIMIT */
  				break;
  			case 'j':			/* jobs */
  				benchmarking_option_set = true;
  				nthreads = atoi(optarg);
  				if (nthreads <= 0)
  				{
  					fprintf(stderr, "invalid number of threads: \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  #ifndef ENABLE_THREAD_SAFETY
  				if (nthreads != 1)
  				{
  					fprintf(stderr, "threads are not supported on this platform; use -j1\n");
  					exit(1);
  				}
  #endif							/* !ENABLE_THREAD_SAFETY */
  				break;
  			case 'C':
  				benchmarking_option_set = true;
  				is_connect = true;
  				break;
  			case 'r':
  				benchmarking_option_set = true;
  				report_per_command = true;
  				break;
  			case 's':
  				scale_given = true;
  				scale = atoi(optarg);
  				if (scale <= 0)
  				{
  					fprintf(stderr, "invalid scaling factor: \"%s\"\n", optarg);
  					exit(1);
  				}
  				break;
  			case 't':
  				benchmarking_option_set = true;
  				nxacts = atoi(optarg);
  				if (nxacts <= 0)
  				{
  					fprintf(stderr, "invalid number of transactions: \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  				break;
  			case 'T':
  				benchmarking_option_set = true;
  				duration = atoi(optarg);
  				if (duration <= 0)
  				{
  					fprintf(stderr, "invalid duration: \"%s\"\n", optarg);
  					exit(1);
  				}
  				break;
  			case 'U':
  				login = pg_strdup(optarg);
  				break;
  			case 'l':
  				benchmarking_option_set = true;
  				use_log = true;
  				break;
  			case 'q':
  				initialization_option_set = true;
  				use_quiet = true;
  				break;
  			case 'b':
  				if (strcmp(optarg, "list") == 0)
  				{
  					listAvailableScripts();
  					exit(0);
  				}
  				weight = parseScriptWeight(optarg, &script);
  				process_builtin(findBuiltin(script), weight);
  				benchmarking_option_set = true;
  				internal_script_used = true;
  				break;
  			case 'S':
  				process_builtin(findBuiltin("select-only"), 1);
  				benchmarking_option_set = true;
  				internal_script_used = true;
  				break;
  			case 'N':
  				process_builtin(findBuiltin("simple-update"), 1);
  				benchmarking_option_set = true;
  				internal_script_used = true;
  				break;
  			case 'f':
  				weight = parseScriptWeight(optarg, &script);
  				process_file(script, weight);
  				benchmarking_option_set = true;
  				break;
  			case 'D':
  				{
  					char	   *p;
  
  					benchmarking_option_set = true;
  
  					if ((p = strchr(optarg, '=')) == NULL || p == optarg || *(p + 1) == '\0')
  					{
  						fprintf(stderr, "invalid variable definition: \"%s\"\n",
  								optarg);
  						exit(1);
  					}
  
  					*p++ = '\0';
  					if (!putVariable(&state[0], "option", optarg, p))
  						exit(1);
  				}
  				break;
  			case 'F':
  				initialization_option_set = true;
  				fillfactor = atoi(optarg);
  				if (fillfactor < 10 || fillfactor > 100)
  				{
  					fprintf(stderr, "invalid fillfactor: \"%s\"\n", optarg);
  					exit(1);
  				}
  				break;
  			case 'M':
  				benchmarking_option_set = true;
  				for (querymode = 0; querymode < NUM_QUERYMODE; querymode++)
  					if (strcmp(optarg, QUERYMODE[querymode]) == 0)
  						break;
  				if (querymode >= NUM_QUERYMODE)
  				{
  					fprintf(stderr, "invalid query mode (-M): \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  				break;
  			case 'P':
  				benchmarking_option_set = true;
  				progress = atoi(optarg);
  				if (progress <= 0)
  				{
  					fprintf(stderr, "invalid thread progress delay: \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  				break;
  			case 'R':
  				{
  					/* get a double from the beginning of option value */
  					double		throttle_value = atof(optarg);
  
  					benchmarking_option_set = true;
  
  					if (throttle_value <= 0.0)
  					{
  						fprintf(stderr, "invalid rate limit: \"%s\"\n", optarg);
  						exit(1);
  					}
  					/* Invert rate limit into per-transaction delay in usec */
  					throttle_delay = 1000000.0 / throttle_value;
  				}
  				break;
  			case 'L':
  				{
  					double		limit_ms = atof(optarg);
  
  					if (limit_ms <= 0.0)
  					{
  						fprintf(stderr, "invalid latency limit: \"%s\"\n",
  								optarg);
  						exit(1);
  					}
  					benchmarking_option_set = true;
  					latency_limit = (int64) (limit_ms * 1000);
  				}
  				break;
  			case 1:				/* unlogged-tables */
  				initialization_option_set = true;
  				unlogged_tables = true;
  				break;
  			case 2:				/* tablespace */
  				initialization_option_set = true;
  				tablespace = pg_strdup(optarg);
  				break;
  			case 3:				/* index-tablespace */
  				initialization_option_set = true;
  				index_tablespace = pg_strdup(optarg);
  				break;
  			case 4:				/* sampling-rate */
  				benchmarking_option_set = true;
  				sample_rate = atof(optarg);
  				if (sample_rate <= 0.0 || sample_rate > 1.0)
  				{
  					fprintf(stderr, "invalid sampling rate: \"%s\"\n", optarg);
  					exit(1);
  				}
  				break;
  			case 5:				/* aggregate-interval */
  				benchmarking_option_set = true;
  				agg_interval = atoi(optarg);
  				if (agg_interval <= 0)
  				{
  					fprintf(stderr, "invalid number of seconds for aggregation: \"%s\"\n",
  							optarg);
  					exit(1);
  				}
  				break;
  			case 6:				/* progress-timestamp */
  				progress_timestamp = true;
  				benchmarking_option_set = true;
  				break;
  			case 7:				/* log-prefix */
  				benchmarking_option_set = true;
  				logfile_prefix = pg_strdup(optarg);
  				break;
  			case 8:				/* foreign-keys */
  				initialization_option_set = true;
  				foreign_keys = true;
  				break;
  			case 9:				/* random-seed */
  				benchmarking_option_set = true;
  				if (!set_random_seed(optarg))
  				{
  					fprintf(stderr, "error while setting random seed from --random-seed option\n");
  					exit(1);
  				}
  				break;
  			default:
  				fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
  				exit(1);
  				break;
  		}
  	}
  
  	/* set default script if none */
  	if (num_scripts == 0 && !is_init_mode)
  	{
  		process_builtin(findBuiltin("tpcb-like"), 1);
  		benchmarking_option_set = true;
  		internal_script_used = true;
  	}
  
  	/* complete SQL command initialization and compute total weight */
  	for (i = 0; i < num_scripts; i++)
  	{
  		Command   **commands = sql_script[i].commands;
  
  		for (int j = 0; commands[j] != NULL; j++)
  			if (commands[j]->type == SQL_COMMAND)
  				postprocess_sql_command(commands[j]);
  
  		/* cannot overflow: weight is 32b, total_weight 64b */
  		total_weight += sql_script[i].weight;
  	}
  
  	if (total_weight == 0 && !is_init_mode)
  	{
  		fprintf(stderr, "total script weight must not be zero\n");
  		exit(1);
  	}
  
  	/* show per script stats if several scripts are used */
  	if (num_scripts > 1)
  		per_script_stats = true;
  
  	/*
  	 * Don't need more threads than there are clients.  (This is not merely an
  	 * optimization; throttle_delay is calculated incorrectly below if some
  	 * threads have no clients assigned to them.)
  	 */
  	if (nthreads > nclients)
  		nthreads = nclients;
  
  	/*
  	 * Convert throttle_delay to a per-thread delay time.  Note that this
  	 * might be a fractional number of usec, but that's OK, since it's just
  	 * the center of a Poisson distribution of delays.
  	 */
  	throttle_delay *= nthreads;
  
  	if (argc > optind)
  		dbName = argv[optind];
  	else
  	{
  		if ((env = getenv("PGDATABASE")) != NULL && *env != '\0')
  			dbName = env;
  		else if (login != NULL && *login != '\0')
  			dbName = login;
  		else
  			dbName = "";
  	}
  
  	if (is_init_mode)
  	{
  		if (benchmarking_option_set)
  		{
  			fprintf(stderr, "some of the specified options cannot be used in initialization (-i) mode\n");
  			exit(1);
  		}
  
  		if (initialize_steps == NULL)
  			initialize_steps = pg_strdup(DEFAULT_INIT_STEPS);
  
  		if (is_no_vacuum)
  		{
  			/* Remove any vacuum step in initialize_steps */
  			char	   *p;
  
  			while ((p = strchr(initialize_steps, 'v')) != NULL)
  				*p = ' ';
  		}
  
  		if (foreign_keys)
  		{
  			/* Add 'f' to end of initialize_steps, if not already there */
  			if (strchr(initialize_steps, 'f') == NULL)
  			{
  				initialize_steps = (char *)
  					pg_realloc(initialize_steps,
  							   strlen(initialize_steps) + 2);
  				strcat(initialize_steps, "f");
  			}
  		}
  
  		runInitSteps(initialize_steps);
  		exit(0);
  	}
  	else
  	{
  		if (initialization_option_set)
  		{
  			fprintf(stderr, "some of the specified options cannot be used in benchmarking mode\n");
  			exit(1);
  		}
  	}
  
  	if (nxacts > 0 && duration > 0)
  	{
  		fprintf(stderr, "specify either a number of transactions (-t) or a duration (-T), not both\n");
  		exit(1);
  	}
  
  	/* Use DEFAULT_NXACTS if neither nxacts nor duration is specified. */
  	if (nxacts <= 0 && duration <= 0)
  		nxacts = DEFAULT_NXACTS;
  
  	/* --sampling-rate may be used only with -l */
  	if (sample_rate > 0.0 && !use_log)
  	{
  		fprintf(stderr, "log sampling (--sampling-rate) is allowed only when logging transactions (-l)\n");
  		exit(1);
  	}
  
  	/* --sampling-rate may not be used with --aggregate-interval */
  	if (sample_rate > 0.0 && agg_interval > 0)
  	{
  		fprintf(stderr, "log sampling (--sampling-rate) and aggregation (--aggregate-interval) cannot be used at the same time\n");
  		exit(1);
  	}
  
  	if (agg_interval > 0 && !use_log)
  	{
  		fprintf(stderr, "log aggregation is allowed only when actually logging transactions\n");
  		exit(1);
  	}
  
  	if (!use_log && logfile_prefix)
  	{
  		fprintf(stderr, "log file prefix (--log-prefix) is allowed only when logging transactions (-l)\n");
  		exit(1);
  	}
  
  	if (duration > 0 && agg_interval > duration)
  	{
  		fprintf(stderr, "number of seconds for aggregation (%d) must not be higher than test duration (%d)\n", agg_interval, duration);
  		exit(1);
  	}
  
  	if (duration > 0 && agg_interval > 0 && duration % agg_interval != 0)
  	{
  		fprintf(stderr, "duration (%d) must be a multiple of aggregation interval (%d)\n", duration, agg_interval);
  		exit(1);
  	}
  
  	if (progress_timestamp && progress == 0)
  	{
  		fprintf(stderr, "--progress-timestamp is allowed only under --progress\n");
  		exit(1);
  	}
  
  	/*
  	 * save main process id in the global variable because process id will be
  	 * changed after fork.
  	 */
  	main_pid = (int) getpid();
  
  	if (nclients > 1)
  	{
  		state = (CState *) pg_realloc(state, sizeof(CState) * nclients);
  		memset(state + 1, 0, sizeof(CState) * (nclients - 1));
  
  		/* copy any -D switch values to all clients */
  		for (i = 1; i < nclients; i++)
  		{
  			int			j;
  
  			state[i].id = i;
  			for (j = 0; j < state[0].nvariables; j++)
  			{
  				Variable   *var = &state[0].variables[j];
  
  				if (var->value.type != PGBT_NO_VALUE)
  				{
  					if (!putVariableValue(&state[i], "startup",
  										  var->name, &var->value))
  						exit(1);
  				}
  				else
  				{
  					if (!putVariable(&state[i], "startup",
  									 var->name, var->svalue))
  						exit(1);
  				}
  			}
  		}
  	}
  
  	/* other CState initializations */
  	for (i = 0; i < nclients; i++)
  	{
  		state[i].cstack = conditional_stack_create();
  		initRandomState(&state[i].cs_func_rs);
  	}
  
  	if (debug)
  	{
  		if (duration <= 0)
  			printf("pghost: %s pgport: %s nclients: %d nxacts: %d dbName: %s\n",
  				   pghost, pgport, nclients, nxacts, dbName);
  		else
  			printf("pghost: %s pgport: %s nclients: %d duration: %d dbName: %s\n",
  				   pghost, pgport, nclients, duration, dbName);
  	}
  
  	/* opening connection... */
  	con = doConnect();
  	if (con == NULL)
  		exit(1);
  
  	if (PQstatus(con) == CONNECTION_BAD)
  	{
  		fprintf(stderr, "connection to database \"%s\" failed\n", dbName);
  		fprintf(stderr, "%s", PQerrorMessage(con));
  		exit(1);
  	}
  
  	if (internal_script_used)
  	{
  		/*
  		 * get the scaling factor that should be same as count(*) from
  		 * pgbench_branches if this is not a custom query
  		 */
  		res = PQexec(con, "select count(*) from pgbench_branches");
  		if (PQresultStatus(res) != PGRES_TUPLES_OK)
  		{
  			char	   *sqlState = PQresultErrorField(res, PG_DIAG_SQLSTATE);
  
  			fprintf(stderr, "%s", PQerrorMessage(con));
  			if (sqlState && strcmp(sqlState, ERRCODE_UNDEFINED_TABLE) == 0)
  			{
  				fprintf(stderr, "Perhaps you need to do initialization (\"pgbench -i\") in database \"%s\"\n", PQdb(con));
  			}
  
  			exit(1);
  		}
  		scale = atoi(PQgetvalue(res, 0, 0));
  		if (scale < 0)
  		{
  			fprintf(stderr, "invalid count(*) from pgbench_branches: \"%s\"\n",
  					PQgetvalue(res, 0, 0));
  			exit(1);
  		}
  		PQclear(res);
  
  		/* warn if we override user-given -s switch */
  		if (scale_given)
  			fprintf(stderr,
  					"scale option ignored, using count from pgbench_branches table (%d)\n",
  					scale);
  	}
  
  	/*
  	 * :scale variables normally get -s or database scale, but don't override
  	 * an explicit -D switch
  	 */
  	if (lookupVariable(&state[0], "scale") == NULL)
  	{
  		for (i = 0; i < nclients; i++)
  		{
  			if (!putVariableInt(&state[i], "startup", "scale", scale))
  				exit(1);
  		}
  	}
  
  	/*
  	 * Define a :client_id variable that is unique per connection. But don't
  	 * override an explicit -D switch.
  	 */
  	if (lookupVariable(&state[0], "client_id") == NULL)
  	{
  		for (i = 0; i < nclients; i++)
  			if (!putVariableInt(&state[i], "startup", "client_id", i))
  				exit(1);
  	}
  
  	/* set default seed for hash functions */
  	if (lookupVariable(&state[0], "default_seed") == NULL)
  	{
  		uint64		seed =
  		((uint64) pg_jrand48(base_random_sequence.xseed) & 0xFFFFFFFF) |
  		(((uint64) pg_jrand48(base_random_sequence.xseed) & 0xFFFFFFFF) << 32);
  
  		for (i = 0; i < nclients; i++)
  			if (!putVariableInt(&state[i], "startup", "default_seed", (int64) seed))
  				exit(1);
  	}
  
  	/* set random seed unless overwritten */
  	if (lookupVariable(&state[0], "random_seed") == NULL)
  	{
  		for (i = 0; i < nclients; i++)
  			if (!putVariableInt(&state[i], "startup", "random_seed", random_seed))
  				exit(1);
  	}
  
  	if (!is_no_vacuum)
  	{
  		fprintf(stderr, "starting vacuum...");
  		tryExecuteStatement(con, "vacuum pgbench_branches");
  		tryExecuteStatement(con, "vacuum pgbench_tellers");
  		tryExecuteStatement(con, "truncate pgbench_history");
  		fprintf(stderr, "end.\n");
  
  		if (do_vacuum_accounts)
  		{
  			fprintf(stderr, "starting vacuum pgbench_accounts...");
  			tryExecuteStatement(con, "vacuum analyze pgbench_accounts");
  			fprintf(stderr, "end.\n");
  		}
  	}
  	PQfinish(con);
  
  	/* set up thread data structures */
  	threads = (TState *) pg_malloc(sizeof(TState) * nthreads);
  	nclients_dealt = 0;
  
  	for (i = 0; i < nthreads; i++)
  	{
  		TState	   *thread = &threads[i];
  
  		thread->tid = i;
  		thread->state = &state[nclients_dealt];
  		thread->nstate =
  			(nclients - nclients_dealt + nthreads - i - 1) / (nthreads - i);
  		initRandomState(&thread->ts_choose_rs);
  		initRandomState(&thread->ts_throttle_rs);
  		initRandomState(&thread->ts_sample_rs);
  		thread->logfile = NULL; /* filled in later */
  		thread->latency_late = 0;
  		initStats(&thread->stats, 0);
  
  		nclients_dealt += thread->nstate;
  	}
  
  	/* all clients must be assigned to a thread */
  	Assert(nclients_dealt == nclients);
  
  	/* get start up time */
  	INSTR_TIME_SET_CURRENT(start_time);
  
  	/* set alarm if duration is specified. */
  	if (duration > 0)
  		setalarm(duration);
  
  	/* start threads */
  #ifdef ENABLE_THREAD_SAFETY
  	for (i = 0; i < nthreads; i++)
  	{
  		TState	   *thread = &threads[i];
  
  		INSTR_TIME_SET_CURRENT(thread->start_time);
  
  		/* compute when to stop */
  		if (duration > 0)
  			end_time = INSTR_TIME_GET_MICROSEC(thread->start_time) +
  				(int64) 1000000 * duration;
  
  		/* the first thread (i = 0) is executed by main thread */
  		if (i > 0)
  		{
  			int			err = pthread_create(&thread->thread, NULL, threadRun, thread);
  
  			if (err != 0 || thread->thread == INVALID_THREAD)
  			{
  				fprintf(stderr, "could not create thread: %s\n", strerror(err));
  				exit(1);
  			}
  		}
  		else
  		{
  			thread->thread = INVALID_THREAD;
  		}
  	}
  #else
  	INSTR_TIME_SET_CURRENT(threads[0].start_time);
  	/* compute when to stop */
  	if (duration > 0)
  		end_time = INSTR_TIME_GET_MICROSEC(threads[0].start_time) +
  			(int64) 1000000 * duration;
  	threads[0].thread = INVALID_THREAD;
  #endif							/* ENABLE_THREAD_SAFETY */
  
  	/* wait for threads and accumulate results */
  	initStats(&stats, 0);
  	INSTR_TIME_SET_ZERO(conn_total_time);
  	for (i = 0; i < nthreads; i++)
  	{
  		TState	   *thread = &threads[i];
  
  #ifdef ENABLE_THREAD_SAFETY
  		if (threads[i].thread == INVALID_THREAD)
  			/* actually run this thread directly in the main thread */
  			(void) threadRun(thread);
  		else
  			/* wait of other threads. should check that 0 is returned? */
  			pthread_join(thread->thread, NULL);
  #else
  		(void) threadRun(thread);
  #endif							/* ENABLE_THREAD_SAFETY */
  
  		for (int j = 0; j < thread->nstate; j++)
  			if (thread->state[j].state == CSTATE_ABORTED)
  				exit_code = 2;
  
  		/* aggregate thread level stats */
  		mergeSimpleStats(&stats.latency, &thread->stats.latency);
  		mergeSimpleStats(&stats.lag, &thread->stats.lag);
  		stats.cnt += thread->stats.cnt;
  		stats.skipped += thread->stats.skipped;
  		latency_late += thread->latency_late;
  		INSTR_TIME_ADD(conn_total_time, thread->conn_time);
  	}
  	disconnect_all(state, nclients);
  
  	/*
  	 * XXX We compute results as though every client of every thread started
  	 * and finished at the same time.  That model can diverge noticeably from
  	 * reality for a short benchmark run involving relatively many threads.
  	 * The first thread may process notably many transactions before the last
  	 * thread begins.  Improving the model alone would bring limited benefit,
  	 * because performance during those periods of partial thread count can
  	 * easily exceed steady state performance.  This is one of the many ways
  	 * short runs convey deceptive performance figures.
  	 */
  	INSTR_TIME_SET_CURRENT(total_time);
  	INSTR_TIME_SUBTRACT(total_time, start_time);
  	printResults(&stats, total_time, conn_total_time, latency_late);
  
  	if (exit_code != 0)
  		fprintf(stderr, "Run was aborted; the above results are incomplete.\n");
  
  	return exit_code;
  }
  
  static void *
  threadRun(void *arg)
  {
  	TState	   *thread = (TState *) arg;
  	CState	   *state = thread->state;
  	instr_time	start,
  				end;
  	int			nstate = thread->nstate;
  	int			remains = nstate;	/* number of remaining clients */
  	socket_set *sockets = alloc_socket_set(nstate);
  	int			i;
  
  	/* for reporting progress: */
  	int64		thread_start = INSTR_TIME_GET_MICROSEC(thread->start_time);
  	int64		last_report = thread_start;
  	int64		next_report = last_report + (int64) progress * 1000000;
  	StatsData	last,
  				aggs;
  
  	/*
  	 * Initialize throttling rate target for all of the thread's clients.  It
  	 * might be a little more accurate to reset thread->start_time here too.
  	 * The possible drift seems too small relative to typical throttle delay
  	 * times to worry about it.
  	 */
  	INSTR_TIME_SET_CURRENT(start);
  	thread->throttle_trigger = INSTR_TIME_GET_MICROSEC(start);
  
  	INSTR_TIME_SET_ZERO(thread->conn_time);
  
  	initStats(&aggs, time(NULL));
  	last = aggs;
  
  	/* open log file if requested */
  	if (use_log)
  	{
  		char		logpath[MAXPGPATH];
  		char	   *prefix = logfile_prefix ? logfile_prefix : "pgbench_log";
  
  		if (thread->tid == 0)
  			snprintf(logpath, sizeof(logpath), "%s.%d", prefix, main_pid);
  		else
  			snprintf(logpath, sizeof(logpath), "%s.%d.%d", prefix, main_pid, thread->tid);
  
  		thread->logfile = fopen(logpath, "w");
  
  		if (thread->logfile == NULL)
  		{
  			fprintf(stderr, "could not open logfile \"%s\": %s\n",
  					logpath, strerror(errno));
  			goto done;
  		}
  	}
  
  	if (!is_connect)
  	{
  		/* make connections to the database before starting */
  		for (i = 0; i < nstate; i++)
  		{
  			if ((state[i].con = doConnect()) == NULL)
  				goto done;
  		}
  	}
  
  	/* time after thread and connections set up */
  	INSTR_TIME_SET_CURRENT(thread->conn_time);
  	INSTR_TIME_SUBTRACT(thread->conn_time, thread->start_time);
  
  	/* explicitly initialize the state machines */
  	for (i = 0; i < nstate; i++)
  	{
  		state[i].state = CSTATE_CHOOSE_SCRIPT;
  	}
  
  	/* loop till all clients have terminated */
  	while (remains > 0)
  	{
  		int			nsocks;		/* number of sockets to be waited for */
  		int64		min_usec;
  		int64		now_usec = 0;	/* set this only if needed */
  
  		/*
  		 * identify which client sockets should be checked for input, and
  		 * compute the nearest time (if any) at which we need to wake up.
  		 */
  		clear_socket_set(sockets);
  		nsocks = 0;
  		min_usec = PG_INT64_MAX;
  		for (i = 0; i < nstate; i++)
  		{
  			CState	   *st = &state[i];
  
  			if (st->state == CSTATE_SLEEP || st->state == CSTATE_THROTTLE)
  			{
  				/* a nap from the script, or under throttling */
  				int64		this_usec;
  
  				/* get current time if needed */
  				if (now_usec == 0)
  				{
  					instr_time	now;
  
  					INSTR_TIME_SET_CURRENT(now);
  					now_usec = INSTR_TIME_GET_MICROSEC(now);
  				}
  
  				/* min_usec should be the minimum delay across all clients */
  				this_usec = (st->state == CSTATE_SLEEP ?
  							 st->sleep_until : st->txn_scheduled) - now_usec;
  				if (min_usec > this_usec)
  					min_usec = this_usec;
  			}
  			else if (st->state == CSTATE_WAIT_RESULT)
  			{
  				/*
  				 * waiting for result from server - nothing to do unless the
  				 * socket is readable
  				 */
  				int			sock = PQsocket(st->con);
  
  				if (sock < 0)
  				{
  					fprintf(stderr, "invalid socket: %s",
  							PQerrorMessage(st->con));
  					goto done;
  				}
  
  				add_socket_to_set(sockets, sock, nsocks++);
  			}
  			else if (st->state != CSTATE_ABORTED &&
  					 st->state != CSTATE_FINISHED)
  			{
  				/*
  				 * This client thread is ready to do something, so we don't
  				 * want to wait.  No need to examine additional clients.
  				 */
  				min_usec = 0;
  				break;
  			}
  		}
  
  		/* also wake up to print the next progress report on time */
  		if (progress && min_usec > 0 && thread->tid == 0)
  		{
  			/* get current time if needed */
  			if (now_usec == 0)
  			{
  				instr_time	now;
  
  				INSTR_TIME_SET_CURRENT(now);
  				now_usec = INSTR_TIME_GET_MICROSEC(now);
  			}
  
  			if (now_usec >= next_report)
  				min_usec = 0;
  			else if ((next_report - now_usec) < min_usec)
  				min_usec = next_report - now_usec;
  		}
  
  		/*
  		 * If no clients are ready to execute actions, sleep until we receive
  		 * data on some client socket or the timeout (if any) elapses.
  		 */
  		if (min_usec > 0)
  		{
  			int			rc = 0;
  
  			if (min_usec != PG_INT64_MAX)
  			{
  				if (nsocks > 0)
  				{
  					rc = wait_on_socket_set(sockets, min_usec);
  				}
  				else			/* nothing active, simple sleep */
  				{
  					pg_usleep(min_usec);
  				}
  			}
  			else				/* no explicit delay, wait without timeout */
  			{
  				rc = wait_on_socket_set(sockets, 0);
  			}
  
  			if (rc < 0)
  			{
  				if (errno == EINTR)
  				{
  					/* On EINTR, go back to top of loop */
  					continue;
  				}
  				/* must be something wrong */
  				fprintf(stderr, "%s() failed: %s\n", SOCKET_WAIT_METHOD, strerror(errno));
  				goto done;
  			}
  		}
  		else
  		{
  			/* min_usec <= 0, i.e. something needs to be executed now */
  
  			/* If we didn't wait, don't try to read any data */
  			clear_socket_set(sockets);
  		}
  
  		/* ok, advance the state machine of each connection */
  		nsocks = 0;
  		for (i = 0; i < nstate; i++)
  		{
  			CState	   *st = &state[i];
  
  			if (st->state == CSTATE_WAIT_RESULT)
  			{
  				/* don't call advanceConnectionState unless data is available */
  				int			sock = PQsocket(st->con);
  
  				if (sock < 0)
  				{
  					fprintf(stderr, "invalid socket: %s",
  							PQerrorMessage(st->con));
  					goto done;
  				}
  
  				if (!socket_has_input(sockets, sock, nsocks++))
  					continue;
  			}
  			else if (st->state == CSTATE_FINISHED ||
  					 st->state == CSTATE_ABORTED)
  			{
  				/* this client is done, no need to consider it anymore */
  				continue;
  			}
  
  			advanceConnectionState(thread, st, &aggs);
  
  			/*
  			 * If advanceConnectionState changed client to finished state,
  			 * that's one less client that remains.
  			 */
  			if (st->state == CSTATE_FINISHED || st->state == CSTATE_ABORTED)
  				remains--;
  		}
  
  		/* progress report is made by thread 0 for all threads */
  		if (progress && thread->tid == 0)
  		{
  			instr_time	now_time;
  			int64		now;
  
  			INSTR_TIME_SET_CURRENT(now_time);
  			now = INSTR_TIME_GET_MICROSEC(now_time);
  			if (now >= next_report)
  			{
  				/*
  				 * Horrible hack: this relies on the thread pointer we are
  				 * passed to be equivalent to threads[0], that is the first
  				 * entry of the threads array.  That is why this MUST be done
  				 * by thread 0 and not any other.
  				 */
  				printProgressReport(thread, thread_start, now,
  									&last, &last_report);
  
  				/*
  				 * Ensure that the next report is in the future, in case
  				 * pgbench/postgres got stuck somewhere.
  				 */
  				do
  				{
  					next_report += (int64) progress * 1000000;
  				} while (now >= next_report);
  			}
  		}
  	}
  
  done:
  	INSTR_TIME_SET_CURRENT(start);
  	disconnect_all(state, nstate);
  	INSTR_TIME_SET_CURRENT(end);
  	INSTR_TIME_ACCUM_DIFF(thread->conn_time, end, start);
  	if (thread->logfile)
  	{
  		if (agg_interval > 0)
  		{
  			/* log aggregated but not yet reported transactions */
  			doLog(thread, state, &aggs, false, 0, 0);
  		}
  		fclose(thread->logfile);
  		thread->logfile = NULL;
  	}
  	free_socket_set(sockets);
  	return NULL;
  }
  
  static void
  finishCon(CState *st)
  {
  	if (st->con != NULL)
  	{
  		PQfinish(st->con);
  		st->con = NULL;
  	}
  }
  
  /*
   * Support for duration option: set timer_exceeded after so many seconds.
   */
  
  #ifndef WIN32
  
  static void
  handle_sig_alarm(SIGNAL_ARGS)
  {
  	timer_exceeded = true;
  }
  
  static void
  setalarm(int seconds)
  {
  	pqsignal(SIGALRM, handle_sig_alarm);
  	alarm(seconds);
  }
  
  #else							/* WIN32 */
  
  static VOID CALLBACK
  win32_timer_callback(PVOID lpParameter, BOOLEAN TimerOrWaitFired)
  {
  	timer_exceeded = true;
  }
  
  static void
  setalarm(int seconds)
  {
  	HANDLE		queue;
  	HANDLE		timer;
  
  	/* This function will be called at most once, so we can cheat a bit. */
  	queue = CreateTimerQueue();
  	if (seconds > ((DWORD) -1) / 1000 ||
  		!CreateTimerQueueTimer(&timer, queue,
  							   win32_timer_callback, NULL, seconds * 1000, 0,
  							   WT_EXECUTEINTIMERTHREAD | WT_EXECUTEONLYONCE))
  	{
  		fprintf(stderr, "failed to set timer\n");
  		exit(1);
  	}
  }
  
  #endif							/* WIN32 */
  
  
  /*
   * These functions provide an abstraction layer that hides the syscall
   * we use to wait for input on a set of sockets.
   *
   * Currently there are two implementations, based on ppoll(2) and select(2).
   * ppoll() is preferred where available due to its typically higher ceiling
   * on the number of usable sockets.  We do not use the more-widely-available
   * poll(2) because it only offers millisecond timeout resolution, which could
   * be problematic with high --rate settings.
   *
   * Function APIs:
   *
   * alloc_socket_set: allocate an empty socket set with room for up to
   *		"count" sockets.
   *
   * free_socket_set: deallocate a socket set.
   *
   * clear_socket_set: reset a socket set to empty.
   *
   * add_socket_to_set: add socket with indicated FD to slot "idx" in the
   *		socket set.  Slots must be filled in order, starting with 0.
   *
   * wait_on_socket_set: wait for input on any socket in set, or for timeout
   *		to expire.  timeout is measured in microseconds; 0 means wait forever.
   *		Returns result code of underlying syscall (>=0 if OK, else see errno).
   *
   * socket_has_input: after waiting, call this to see if given socket has
   *		input.  fd and idx parameters should match some previous call to
   *		add_socket_to_set.
   *
   * Note that wait_on_socket_set destructively modifies the state of the
   * socket set.  After checking for input, caller must apply clear_socket_set
   * and add_socket_to_set again before waiting again.
   */
  
  #ifdef POLL_USING_PPOLL
  
  static socket_set *
  alloc_socket_set(int count)
  {
  	socket_set *sa;
  
  	sa = (socket_set *) pg_malloc0(offsetof(socket_set, pollfds) +
  								   sizeof(struct pollfd) * count);
  	sa->maxfds = count;
  	sa->curfds = 0;
  	return sa;
  }
  
  static void
  free_socket_set(socket_set *sa)
  {
  	pg_free(sa);
  }
  
  static void
  clear_socket_set(socket_set *sa)
  {
  	sa->curfds = 0;
  }
  
  static void
  add_socket_to_set(socket_set *sa, int fd, int idx)
  {
  	Assert(idx < sa->maxfds && idx == sa->curfds);
  	sa->pollfds[idx].fd = fd;
  	sa->pollfds[idx].events = POLLIN;
  	sa->pollfds[idx].revents = 0;
  	sa->curfds++;
  }
  
  static int
  wait_on_socket_set(socket_set *sa, int64 usecs)
  {
  	if (usecs > 0)
  	{
  		struct timespec timeout;
  
  		timeout.tv_sec = usecs / 1000000;
  		timeout.tv_nsec = (usecs % 1000000) * 1000;
  		return ppoll(sa->pollfds, sa->curfds, &timeout, NULL);
  	}
  	else
  	{
  		return ppoll(sa->pollfds, sa->curfds, NULL, NULL);
  	}
  }
  
  static bool
  socket_has_input(socket_set *sa, int fd, int idx)
  {
  	/*
  	 * In some cases, threadRun will apply clear_socket_set and then try to
  	 * apply socket_has_input anyway with arguments that it used before that,
  	 * or might've used before that except that it exited its setup loop
  	 * early.  Hence, if the socket set is empty, silently return false
  	 * regardless of the parameters.  If it's not empty, we can Assert that
  	 * the parameters match a previous call.
  	 */
  	if (sa->curfds == 0)
  		return false;
  
  	Assert(idx < sa->curfds && sa->pollfds[idx].fd == fd);
  	return (sa->pollfds[idx].revents & POLLIN) != 0;
  }
  
  #endif							/* POLL_USING_PPOLL */
  
  #ifdef POLL_USING_SELECT
  
  static socket_set *
  alloc_socket_set(int count)
  {
  	return (socket_set *) pg_malloc0(sizeof(socket_set));
  }
  
  static void
  free_socket_set(socket_set *sa)
  {
  	pg_free(sa);
  }
  
  static void
  clear_socket_set(socket_set *sa)
  {
  	FD_ZERO(&sa->fds);
  	sa->maxfd = -1;
  }
  
  static void
  add_socket_to_set(socket_set *sa, int fd, int idx)
  {
  	if (fd < 0 || fd >= FD_SETSIZE)
  	{
  		/*
  		 * Doing a hard exit here is a bit grotty, but it doesn't seem worth
  		 * complicating the API to make it less grotty.
  		 */
  		fprintf(stderr, "too many client connections for select()\n");
  		exit(1);
  	}
  	FD_SET(fd, &sa->fds);
  	if (fd > sa->maxfd)
  		sa->maxfd = fd;
  }
  
  static int
  wait_on_socket_set(socket_set *sa, int64 usecs)
  {
  	if (usecs > 0)
  	{
  		struct timeval timeout;
  
  		timeout.tv_sec = usecs / 1000000;
  		timeout.tv_usec = usecs % 1000000;
  		return select(sa->maxfd + 1, &sa->fds, NULL, NULL, &timeout);
  	}
  	else
  	{
  		return select(sa->maxfd + 1, &sa->fds, NULL, NULL, NULL);
  	}
  }
  
  static bool
  socket_has_input(socket_set *sa, int fd, int idx)
  {
  	return (FD_ISSET(fd, &sa->fds) != 0);
  }
  
  #endif							/* POLL_USING_SELECT */
  
  
  /* partial pthread implementation for Windows */
  
  #ifdef WIN32
  
  typedef struct win32_pthread
  {
  	HANDLE		handle;
  	void	   *(*routine) (void *);
  	void	   *arg;
  	void	   *result;
  } win32_pthread;
  
  static unsigned __stdcall
  win32_pthread_run(void *arg)
  {
  	win32_pthread *th = (win32_pthread *) arg;
  
  	th->result = th->routine(th->arg);
  
  	return 0;
  }
  
  static int
  pthread_create(pthread_t *thread,
  			   pthread_attr_t *attr,
  			   void *(*start_routine) (void *),
  			   void *arg)
  {
  	int			save_errno;
  	win32_pthread *th;
  
  	th = (win32_pthread *) pg_malloc(sizeof(win32_pthread));
  	th->routine = start_routine;
  	th->arg = arg;
  	th->result = NULL;
  
  	th->handle = (HANDLE) _beginthreadex(NULL, 0, win32_pthread_run, th, 0, NULL);
  	if (th->handle == NULL)
  	{
  		save_errno = errno;
  		free(th);
  		return save_errno;
  	}
  
  	*thread = th;
  	return 0;
  }
  
  static int
  pthread_join(pthread_t th, void **thread_return)
  {
  	if (th == NULL || th->handle == NULL)
  		return errno = EINVAL;
  
  	if (WaitForSingleObject(th->handle, INFINITE) != WAIT_OBJECT_0)
  	{
  		_dosmaperr(GetLastError());
  		return errno;
  	}
  
  	if (thread_return)
  		*thread_return = th->result;
  
  	CloseHandle(th->handle);
  	free(th);
  	return 0;
  }
  
  #endif							/* WIN32 */
  