text: /* ----------
   *	pgstat.h
   *
   *	Definitions for the PostgreSQL statistics collector daemon.
   *
   *	Copyright (c) 2001-2022, PostgreSQL Global Development Group
   *
   *	src/include/pgstat.h
   * ----------
   */
  #ifndef PGSTAT_H
  #define PGSTAT_H
  
  #include "datatype/timestamp.h"
  #include "portability/instr_time.h"
  #include "postmaster/pgarch.h"	/* for MAX_XFN_CHARS */
  #include "replication/logicalproto.h"
  #include "utils/backend_progress.h" /* for backward compatibility */
  #include "utils/backend_status.h"	/* for backward compatibility */
  #include "utils/hsearch.h"
  #include "utils/relcache.h"
  #include "utils/wait_event.h"	/* for backward compatibility */
  
  
  /* ----------
   * Paths for the statistics files (relative to installation's $PGDATA).
   * ----------
   */
  #define PGSTAT_STAT_PERMANENT_DIRECTORY		"pg_stat"
  #define PGSTAT_STAT_PERMANENT_FILENAME		"pg_stat/global.stat"
  #define PGSTAT_STAT_PERMANENT_TMPFILE		"pg_stat/global.tmp"
  
  /* Default directory to store temporary statistics data in */
  #define PG_STAT_TMP_DIR		"pg_stat_tmp"
  
  
  /* Values for track_functions GUC variable --- order is significant! */
  typedef enum TrackFunctionsLevel
  {
  	TRACK_FUNC_OFF,
  	TRACK_FUNC_PL,
  	TRACK_FUNC_ALL
  }			TrackFunctionsLevel;
  
  /* Values to track the cause of session termination */
  typedef enum SessionEndType
  {
  	DISCONNECT_NOT_YET,			/* still active */
  	DISCONNECT_NORMAL,
  	DISCONNECT_CLIENT_EOF,
  	DISCONNECT_FATAL,
  	DISCONNECT_KILLED
  } SessionEndType;
  
  /* ----------
   * The data type used for counters.
   * ----------
   */
  typedef int64 PgStat_Counter;
  
  /* Possible targets for resetting cluster-wide shared values */
  typedef enum PgStat_Shared_Reset_Target
  {
  	RESET_ARCHIVER,
  	RESET_BGWRITER,
  	RESET_WAL
  } PgStat_Shared_Reset_Target;
  
  /* Possible object types for resetting single counters */
  typedef enum PgStat_Single_Reset_Type
  {
  	RESET_TABLE,
  	RESET_FUNCTION
  } PgStat_Single_Reset_Type;
  
  
  /* ------------------------------------------------------------
   * Structures kept in backend local memory while accumulating counts
   * ------------------------------------------------------------
   */
  
  /* ----------
   * PgStat_FunctionCounts	The actual per-function counts kept by a backend
   *
   * This struct should contain only actual event counters, because we memcmp
   * it against zeroes to detect whether there are any counts to transmit.
   *
   * Note that the time counters are in instr_time format here.  We convert to
   * microseconds in PgStat_Counter format when transmitting to the collector.
   * ----------
   */
  typedef struct PgStat_FunctionCounts
  {
  	PgStat_Counter f_numcalls;
  	instr_time	f_total_time;
  	instr_time	f_self_time;
  } PgStat_FunctionCounts;
  
  /* ----------
   * PgStat_BackendFunctionEntry	Entry in backend's per-function hash table
   * ----------
   */
  typedef struct PgStat_BackendFunctionEntry
  {
  	Oid			f_id;
  	PgStat_FunctionCounts f_counts;
  } PgStat_BackendFunctionEntry;
  
  /*
   * Working state needed to accumulate per-function-call timing statistics.
   */
  typedef struct PgStat_FunctionCallUsage
  {
  	/* Link to function's hashtable entry (must still be there at exit!) */
  	/* NULL means we are not tracking the current function call */
  	PgStat_FunctionCounts *fs;
  	/* Total time previously charged to function, as of function start */
  	instr_time	save_f_total_time;
  	/* Backend-wide total time as of function start */
  	instr_time	save_total;
  	/* system clock as of function start */
  	instr_time	f_start;
  } PgStat_FunctionCallUsage;
  
  /* ----------
   * PgStat_TableCounts			The actual per-table counts kept by a backend
   *
   * This struct should contain only actual event counters, because we memcmp
   * it against zeroes to detect whether there are any counts to transmit.
   * It is a component of PgStat_TableStatus (within-backend state) and
   * PgStat_TableEntry (the transmitted message format).
   *
   * Note: for a table, tuples_returned is the number of tuples successfully
   * fetched by heap_getnext, while tuples_fetched is the number of tuples
   * successfully fetched by heap_fetch under the control of bitmap indexscans.
   * For an index, tuples_returned is the number of index entries returned by
   * the index AM, while tuples_fetched is the number of tuples successfully
   * fetched by heap_fetch under the control of simple indexscans for this index.
   *
   * tuples_inserted/updated/deleted/hot_updated count attempted actions,
   * regardless of whether the transaction committed.  delta_live_tuples,
   * delta_dead_tuples, and changed_tuples are set depending on commit or abort.
   * Note that delta_live_tuples and delta_dead_tuples can be negative!
   * ----------
   */
  typedef struct PgStat_TableCounts
  {
  	PgStat_Counter t_numscans;
  
  	PgStat_Counter t_tuples_returned;
  	PgStat_Counter t_tuples_fetched;
  
  	PgStat_Counter t_tuples_inserted;
  	PgStat_Counter t_tuples_updated;
  	PgStat_Counter t_tuples_deleted;
  	PgStat_Counter t_tuples_hot_updated;
  	bool		t_truncdropped;
  
  	PgStat_Counter t_delta_live_tuples;
  	PgStat_Counter t_delta_dead_tuples;
  	PgStat_Counter t_changed_tuples;
  
  	PgStat_Counter t_blocks_fetched;
  	PgStat_Counter t_blocks_hit;
  } PgStat_TableCounts;
  
  /* ----------
   * PgStat_TableStatus			Per-table status within a backend
   *
   * Many of the event counters are nontransactional, ie, we count events
   * in committed and aborted transactions alike.  For these, we just count
   * directly in the PgStat_TableStatus.  However, delta_live_tuples,
   * delta_dead_tuples, and changed_tuples must be derived from event counts
   * with awareness of whether the transaction or subtransaction committed or
   * aborted.  Hence, we also keep a stack of per-(sub)transaction status
   * records for every table modified in the current transaction.  At commit
   * or abort, we propagate tuples_inserted/updated/deleted up to the
   * parent subtransaction level, or out to the parent PgStat_TableStatus,
   * as appropriate.
   * ----------
   */
  typedef struct PgStat_TableStatus
  {
  	Oid			t_id;			/* table's OID */
  	bool		t_shared;		/* is it a shared catalog? */
  	struct PgStat_TableXactStatus *trans;	/* lowest subxact's counts */
  	PgStat_TableCounts t_counts;	/* event counts to be sent */
  } PgStat_TableStatus;
  
  /* ----------
   * PgStat_TableXactStatus		Per-table, per-subtransaction status
   * ----------
   */
  typedef struct PgStat_TableXactStatus
  {
  	PgStat_Counter tuples_inserted; /* tuples inserted in (sub)xact */
  	PgStat_Counter tuples_updated;	/* tuples updated in (sub)xact */
  	PgStat_Counter tuples_deleted;	/* tuples deleted in (sub)xact */
  	bool		truncdropped;	/* relation truncated/dropped in this
  								 * (sub)xact */
  	/* tuples i/u/d prior to truncate/drop */
  	PgStat_Counter inserted_pre_truncdrop;
  	PgStat_Counter updated_pre_truncdrop;
  	PgStat_Counter deleted_pre_truncdrop;
  	int			nest_level;		/* subtransaction nest level */
  	/* links to other structs for same relation: */
  	struct PgStat_TableXactStatus *upper;	/* next higher subxact if any */
  	PgStat_TableStatus *parent; /* per-table status */
  	/* structs of same subxact level are linked here: */
  	struct PgStat_TableXactStatus *next;	/* next of same subxact */
  } PgStat_TableXactStatus;
  
  
  /* ------------------------------------------------------------
   * Message formats follow
   * ------------------------------------------------------------
   */
  
  /* ----------
   * The types of backend -> collector messages
   * ----------
   */
  typedef enum StatMsgType
  {
  	PGSTAT_MTYPE_DUMMY,
  	PGSTAT_MTYPE_INQUIRY,
  	PGSTAT_MTYPE_TABSTAT,
  	PGSTAT_MTYPE_TABPURGE,
  	PGSTAT_MTYPE_DROPDB,
  	PGSTAT_MTYPE_RESETCOUNTER,
  	PGSTAT_MTYPE_RESETSHAREDCOUNTER,
  	PGSTAT_MTYPE_RESETSINGLECOUNTER,
  	PGSTAT_MTYPE_RESETSLRUCOUNTER,
  	PGSTAT_MTYPE_RESETREPLSLOTCOUNTER,
  	PGSTAT_MTYPE_RESETSUBCOUNTER,
  	PGSTAT_MTYPE_AUTOVAC_START,
  	PGSTAT_MTYPE_VACUUM,
  	PGSTAT_MTYPE_ANALYZE,
  	PGSTAT_MTYPE_ARCHIVER,
  	PGSTAT_MTYPE_BGWRITER,
  	PGSTAT_MTYPE_CHECKPOINTER,
  	PGSTAT_MTYPE_WAL,
  	PGSTAT_MTYPE_SLRU,
  	PGSTAT_MTYPE_FUNCSTAT,
  	PGSTAT_MTYPE_FUNCPURGE,
  	PGSTAT_MTYPE_RECOVERYCONFLICT,
  	PGSTAT_MTYPE_TEMPFILE,
  	PGSTAT_MTYPE_DEADLOCK,
  	PGSTAT_MTYPE_CHECKSUMFAILURE,
  	PGSTAT_MTYPE_REPLSLOT,
  	PGSTAT_MTYPE_CONNECT,
  	PGSTAT_MTYPE_DISCONNECT,
  	PGSTAT_MTYPE_SUBSCRIPTIONDROP,
  	PGSTAT_MTYPE_SUBSCRIPTIONERROR,
  } StatMsgType;
  
  /* ----------
   * PgStat_MsgHdr				The common message header
   * ----------
   */
  typedef struct PgStat_MsgHdr
  {
  	StatMsgType m_type;
  	int			m_size;
  } PgStat_MsgHdr;
  
  /* ----------
   * Space available in a message.  This will keep the UDP packets below 1K,
   * which should fit unfragmented into the MTU of the loopback interface.
   * (Larger values of PGSTAT_MAX_MSG_SIZE would work for that on most
   * platforms, but we're being conservative here.)
   * ----------
   */
  #define PGSTAT_MAX_MSG_SIZE 1000
  #define PGSTAT_MSG_PAYLOAD	(PGSTAT_MAX_MSG_SIZE - sizeof(PgStat_MsgHdr))
  
  
  /* ----------
   * PgStat_MsgDummy				A dummy message, ignored by the collector
   * ----------
   */
  typedef struct PgStat_MsgDummy
  {
  	PgStat_MsgHdr m_hdr;
  } PgStat_MsgDummy;
  
  /* ----------
   * PgStat_MsgInquiry			Sent by a backend to ask the collector
   *								to write the stats file(s).
   *
   * Ordinarily, an inquiry message prompts writing of the global stats file,
   * the stats file for shared catalogs, and the stats file for the specified
   * database.  If databaseid is InvalidOid, only the first two are written.
   *
   * New file(s) will be written only if the existing file has a timestamp
   * older than the specified cutoff_time; this prevents duplicated effort
   * when multiple requests arrive at nearly the same time, assuming that
   * backends send requests with cutoff_times a little bit in the past.
   *
   * clock_time should be the requestor's current local time; the collector
   * uses this to check for the system clock going backward, but it has no
   * effect unless that occurs.  We assume clock_time >= cutoff_time, though.
   * ----------
   */
  typedef struct PgStat_MsgInquiry
  {
  	PgStat_MsgHdr m_hdr;
  	TimestampTz clock_time;		/* observed local clock time */
  	TimestampTz cutoff_time;	/* minimum acceptable file timestamp */
  	Oid			databaseid;		/* requested DB (InvalidOid => shared only) */
  } PgStat_MsgInquiry;
  
  /* ----------
   * PgStat_TableEntry			Per-table info in a MsgTabstat
   * ----------
   */
  typedef struct PgStat_TableEntry
  {
  	Oid			t_id;
  	PgStat_TableCounts t_counts;
  } PgStat_TableEntry;
  
  /* ----------
   * PgStat_MsgTabstat			Sent by the backend to report table
   *								and buffer access statistics.
   * ----------
   */
  #define PGSTAT_NUM_TABENTRIES  \
  	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - 3 * sizeof(int) - 5 * sizeof(PgStat_Counter)) \
  	 / sizeof(PgStat_TableEntry))
  
  typedef struct PgStat_MsgTabstat
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	int			m_nentries;
  	int			m_xact_commit;
  	int			m_xact_rollback;
  	PgStat_Counter m_block_read_time;	/* times in microseconds */
  	PgStat_Counter m_block_write_time;
  	PgStat_Counter m_session_time;
  	PgStat_Counter m_active_time;
  	PgStat_Counter m_idle_in_xact_time;
  	PgStat_TableEntry m_entry[PGSTAT_NUM_TABENTRIES];
  } PgStat_MsgTabstat;
  
  /* ----------
   * PgStat_MsgTabpurge			Sent by the backend to tell the collector
   *								about dead tables.
   * ----------
   */
  #define PGSTAT_NUM_TABPURGE  \
  	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
  	 / sizeof(Oid))
  
  typedef struct PgStat_MsgTabpurge
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	int			m_nentries;
  	Oid			m_tableid[PGSTAT_NUM_TABPURGE];
  } PgStat_MsgTabpurge;
  
  /* ----------
   * PgStat_MsgDropdb				Sent by the backend to tell the collector
   *								about a dropped database
   * ----------
   */
  typedef struct PgStat_MsgDropdb
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  } PgStat_MsgDropdb;
  
  /* ----------
   * PgStat_MsgResetcounter		Sent by the backend to tell the collector
   *								to reset counters
   * ----------
   */
  typedef struct PgStat_MsgResetcounter
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  } PgStat_MsgResetcounter;
  
  /* ----------
   * PgStat_MsgResetsharedcounter Sent by the backend to tell the collector
   *								to reset a shared counter
   * ----------
   */
  typedef struct PgStat_MsgResetsharedcounter
  {
  	PgStat_MsgHdr m_hdr;
  	PgStat_Shared_Reset_Target m_resettarget;
  } PgStat_MsgResetsharedcounter;
  
  /* ----------
   * PgStat_MsgResetsinglecounter Sent by the backend to tell the collector
   *								to reset a single counter
   * ----------
   */
  typedef struct PgStat_MsgResetsinglecounter
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	PgStat_Single_Reset_Type m_resettype;
  	Oid			m_objectid;
  } PgStat_MsgResetsinglecounter;
  
  /* ----------
   * PgStat_MsgResetslrucounter Sent by the backend to tell the collector
   *								to reset a SLRU counter
   * ----------
   */
  typedef struct PgStat_MsgResetslrucounter
  {
  	PgStat_MsgHdr m_hdr;
  	int			m_index;
  } PgStat_MsgResetslrucounter;
  
  /* ----------
   * PgStat_MsgResetreplslotcounter Sent by the backend to tell the collector
   *								to reset replication slot counter(s)
   * ----------
   */
  typedef struct PgStat_MsgResetreplslotcounter
  {
  	PgStat_MsgHdr m_hdr;
  	NameData	m_slotname;
  	bool		clearall;
  } PgStat_MsgResetreplslotcounter;
  
  /* ----------
   * PgStat_MsgResetsubcounter Sent by the backend to tell the collector
   *								to reset subscription counter(s)
   * ----------
   */
  typedef struct PgStat_MsgResetsubcounter
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_subid;		/* InvalidOid means reset all subscription
  								 * stats */
  } PgStat_MsgResetsubcounter;
  
  /* ----------
   * PgStat_MsgAutovacStart		Sent by the autovacuum daemon to signal
   *								that a database is going to be processed
   * ----------
   */
  typedef struct PgStat_MsgAutovacStart
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	TimestampTz m_start_time;
  } PgStat_MsgAutovacStart;
  
  /* ----------
   * PgStat_MsgVacuum				Sent by the backend or autovacuum daemon
   *								after VACUUM
   * ----------
   */
  typedef struct PgStat_MsgVacuum
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	Oid			m_tableoid;
  	bool		m_autovacuum;
  	TimestampTz m_vacuumtime;
  	PgStat_Counter m_live_tuples;
  	PgStat_Counter m_dead_tuples;
  } PgStat_MsgVacuum;
  
  /* ----------
   * PgStat_MsgAnalyze			Sent by the backend or autovacuum daemon
   *								after ANALYZE
   * ----------
   */
  typedef struct PgStat_MsgAnalyze
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	Oid			m_tableoid;
  	bool		m_autovacuum;
  	bool		m_resetcounter;
  	TimestampTz m_analyzetime;
  	PgStat_Counter m_live_tuples;
  	PgStat_Counter m_dead_tuples;
  } PgStat_MsgAnalyze;
  
  /* ----------
   * PgStat_MsgArchiver			Sent by the archiver to update statistics.
   * ----------
   */
  typedef struct PgStat_MsgArchiver
  {
  	PgStat_MsgHdr m_hdr;
  	bool		m_failed;		/* Failed attempt */
  	char		m_xlog[MAX_XFN_CHARS + 1];
  	TimestampTz m_timestamp;
  } PgStat_MsgArchiver;
  
  /* ----------
   * PgStat_MsgBgWriter			Sent by the bgwriter to update statistics.
   * ----------
   */
  typedef struct PgStat_MsgBgWriter
  {
  	PgStat_MsgHdr m_hdr;
  
  	PgStat_Counter m_buf_written_clean;
  	PgStat_Counter m_maxwritten_clean;
  	PgStat_Counter m_buf_alloc;
  } PgStat_MsgBgWriter;
  
  /* ----------
   * PgStat_MsgCheckpointer  Sent by the checkpointer to update statistics.
   * ----------
   */
  typedef struct PgStat_MsgCheckpointer
  {
  	PgStat_MsgHdr m_hdr;
  
  	PgStat_Counter m_timed_checkpoints;
  	PgStat_Counter m_requested_checkpoints;
  	PgStat_Counter m_buf_written_checkpoints;
  	PgStat_Counter m_buf_written_backend;
  	PgStat_Counter m_buf_fsync_backend;
  	PgStat_Counter m_checkpoint_write_time; /* times in milliseconds */
  	PgStat_Counter m_checkpoint_sync_time;
  } PgStat_MsgCheckpointer;
  
  /* ----------
   * PgStat_MsgWal			Sent by backends and background processes to update WAL statistics.
   * ----------
   */
  typedef struct PgStat_MsgWal
  {
  	PgStat_MsgHdr m_hdr;
  	PgStat_Counter m_wal_records;
  	PgStat_Counter m_wal_fpi;
  	uint64		m_wal_bytes;
  	PgStat_Counter m_wal_buffers_full;
  	PgStat_Counter m_wal_write;
  	PgStat_Counter m_wal_sync;
  	PgStat_Counter m_wal_write_time;	/* time spent writing wal records in
  										 * microseconds */
  	PgStat_Counter m_wal_sync_time; /* time spent syncing wal records in
  									 * microseconds */
  } PgStat_MsgWal;
  
  /* ----------
   * PgStat_MsgSLRU			Sent by a backend to update SLRU statistics.
   * ----------
   */
  typedef struct PgStat_MsgSLRU
  {
  	PgStat_MsgHdr m_hdr;
  	PgStat_Counter m_index;
  	PgStat_Counter m_blocks_zeroed;
  	PgStat_Counter m_blocks_hit;
  	PgStat_Counter m_blocks_read;
  	PgStat_Counter m_blocks_written;
  	PgStat_Counter m_blocks_exists;
  	PgStat_Counter m_flush;
  	PgStat_Counter m_truncate;
  } PgStat_MsgSLRU;
  
  /* ----------
   * PgStat_MsgReplSlot	Sent by a backend or a wal sender to update replication
   *						slot statistics.
   * ----------
   */
  typedef struct PgStat_MsgReplSlot
  {
  	PgStat_MsgHdr m_hdr;
  	NameData	m_slotname;
  	bool		m_create;
  	bool		m_drop;
  	PgStat_Counter m_spill_txns;
  	PgStat_Counter m_spill_count;
  	PgStat_Counter m_spill_bytes;
  	PgStat_Counter m_stream_txns;
  	PgStat_Counter m_stream_count;
  	PgStat_Counter m_stream_bytes;
  	PgStat_Counter m_total_txns;
  	PgStat_Counter m_total_bytes;
  } PgStat_MsgReplSlot;
  
  /* ----------
   * PgStat_MsgSubscriptionDrop	Sent by the backend and autovacuum to tell the
   *								collector about the dead subscription.
   * ----------
   */
  typedef struct PgStat_MsgSubscriptionDrop
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_subid;
  } PgStat_MsgSubscriptionDrop;
  
  /* ----------
   * PgStat_MsgSubscriptionError	Sent by the apply worker or the table sync
   *								worker to report an error on the subscription.
   * ----------
   */
  typedef struct PgStat_MsgSubscriptionError
  {
  	PgStat_MsgHdr m_hdr;
  
  	Oid			m_subid;
  	bool		m_is_apply_error;
  } PgStat_MsgSubscriptionError;
  
  /* ----------
   * PgStat_MsgRecoveryConflict	Sent by the backend upon recovery conflict
   * ----------
   */
  typedef struct PgStat_MsgRecoveryConflict
  {
  	PgStat_MsgHdr m_hdr;
  
  	Oid			m_databaseid;
  	int			m_reason;
  } PgStat_MsgRecoveryConflict;
  
  /* ----------
   * PgStat_MsgTempFile	Sent by the backend upon creating a temp file
   * ----------
   */
  typedef struct PgStat_MsgTempFile
  {
  	PgStat_MsgHdr m_hdr;
  
  	Oid			m_databaseid;
  	size_t		m_filesize;
  } PgStat_MsgTempFile;
  
  /* ----------
   * PgStat_FunctionEntry			Per-function info in a MsgFuncstat
   * ----------
   */
  typedef struct PgStat_FunctionEntry
  {
  	Oid			f_id;
  	PgStat_Counter f_numcalls;
  	PgStat_Counter f_total_time;	/* times in microseconds */
  	PgStat_Counter f_self_time;
  } PgStat_FunctionEntry;
  
  /* ----------
   * PgStat_MsgFuncstat			Sent by the backend to report function
   *								usage statistics.
   * ----------
   */
  #define PGSTAT_NUM_FUNCENTRIES	\
  	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
  	 / sizeof(PgStat_FunctionEntry))
  
  typedef struct PgStat_MsgFuncstat
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	int			m_nentries;
  	PgStat_FunctionEntry m_entry[PGSTAT_NUM_FUNCENTRIES];
  } PgStat_MsgFuncstat;
  
  /* ----------
   * PgStat_MsgFuncpurge			Sent by the backend to tell the collector
   *								about dead functions.
   * ----------
   */
  #define PGSTAT_NUM_FUNCPURGE  \
  	((PGSTAT_MSG_PAYLOAD - sizeof(Oid) - sizeof(int))  \
  	 / sizeof(Oid))
  
  typedef struct PgStat_MsgFuncpurge
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	int			m_nentries;
  	Oid			m_functionid[PGSTAT_NUM_FUNCPURGE];
  } PgStat_MsgFuncpurge;
  
  /* ----------
   * PgStat_MsgDeadlock			Sent by the backend to tell the collector
   *								about a deadlock that occurred.
   * ----------
   */
  typedef struct PgStat_MsgDeadlock
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  } PgStat_MsgDeadlock;
  
  /* ----------
   * PgStat_MsgChecksumFailure	Sent by the backend to tell the collector
   *								about checksum failures noticed.
   * ----------
   */
  typedef struct PgStat_MsgChecksumFailure
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	int			m_failurecount;
  	TimestampTz m_failure_time;
  } PgStat_MsgChecksumFailure;
  
  /* ----------
   * PgStat_MsgConnect			Sent by the backend upon connection
   *								establishment
   * ----------
   */
  typedef struct PgStat_MsgConnect
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  } PgStat_MsgConnect;
  
  /* ----------
   * PgStat_MsgDisconnect			Sent by the backend when disconnecting
   * ----------
   */
  typedef struct PgStat_MsgDisconnect
  {
  	PgStat_MsgHdr m_hdr;
  	Oid			m_databaseid;
  	SessionEndType m_cause;
  } PgStat_MsgDisconnect;
  
  /* ----------
   * PgStat_Msg					Union over all possible messages.
   * ----------
   */
  typedef union PgStat_Msg
  {
  	PgStat_MsgHdr msg_hdr;
  	PgStat_MsgDummy msg_dummy;
  	PgStat_MsgInquiry msg_inquiry;
  	PgStat_MsgTabstat msg_tabstat;
  	PgStat_MsgTabpurge msg_tabpurge;
  	PgStat_MsgDropdb msg_dropdb;
  	PgStat_MsgResetcounter msg_resetcounter;
  	PgStat_MsgResetsharedcounter msg_resetsharedcounter;
  	PgStat_MsgResetsinglecounter msg_resetsinglecounter;
  	PgStat_MsgResetslrucounter msg_resetslrucounter;
  	PgStat_MsgResetreplslotcounter msg_resetreplslotcounter;
  	PgStat_MsgResetsubcounter msg_resetsubcounter;
  	PgStat_MsgAutovacStart msg_autovacuum_start;
  	PgStat_MsgVacuum msg_vacuum;
  	PgStat_MsgAnalyze msg_analyze;
  	PgStat_MsgArchiver msg_archiver;
  	PgStat_MsgBgWriter msg_bgwriter;
  	PgStat_MsgCheckpointer msg_checkpointer;
  	PgStat_MsgWal msg_wal;
  	PgStat_MsgSLRU msg_slru;
  	PgStat_MsgFuncstat msg_funcstat;
  	PgStat_MsgFuncpurge msg_funcpurge;
  	PgStat_MsgRecoveryConflict msg_recoveryconflict;
  	PgStat_MsgDeadlock msg_deadlock;
  	PgStat_MsgTempFile msg_tempfile;
  	PgStat_MsgChecksumFailure msg_checksumfailure;
  	PgStat_MsgReplSlot msg_replslot;
  	PgStat_MsgConnect msg_connect;
  	PgStat_MsgDisconnect msg_disconnect;
  	PgStat_MsgSubscriptionError msg_subscriptionerror;
  	PgStat_MsgSubscriptionDrop msg_subscriptiondrop;
  } PgStat_Msg;
  
  
  /* ------------------------------------------------------------
   * Statistic collector data structures follow
   *
   * PGSTAT_FILE_FORMAT_ID should be changed whenever any of these
   * data structures change.
   * ------------------------------------------------------------
   */
  
  #define PGSTAT_FILE_FORMAT_ID	0x01A5BCA6
  
  typedef struct PgStat_ArchiverStats
  {
  	PgStat_Counter archived_count;	/* archival successes */
  	char		last_archived_wal[MAX_XFN_CHARS + 1];	/* last WAL file
  														 * archived */
  	TimestampTz last_archived_timestamp;	/* last archival success time */
  	PgStat_Counter failed_count;	/* failed archival attempts */
  	char		last_failed_wal[MAX_XFN_CHARS + 1]; /* WAL file involved in
  													 * last failure */
  	TimestampTz last_failed_timestamp;	/* last archival failure time */
  	TimestampTz stat_reset_timestamp;
  } PgStat_ArchiverStats;
  
  typedef struct PgStat_BgWriterStats
  {
  	PgStat_Counter buf_written_clean;
  	PgStat_Counter maxwritten_clean;
  	PgStat_Counter buf_alloc;
  	TimestampTz stat_reset_timestamp;
  } PgStat_BgWriterStats;
  
  typedef struct PgStat_CheckpointerStats
  {
  	TimestampTz stats_timestamp;	/* time of stats file update */
  	PgStat_Counter timed_checkpoints;
  	PgStat_Counter requested_checkpoints;
  	PgStat_Counter checkpoint_write_time;	/* times in milliseconds */
  	PgStat_Counter checkpoint_sync_time;
  	PgStat_Counter buf_written_checkpoints;
  	PgStat_Counter buf_written_backend;
  	PgStat_Counter buf_fsync_backend;
  } PgStat_CheckpointerStats;
  
  typedef struct PgStat_StatDBEntry
  {
  	Oid			databaseid;
  	PgStat_Counter n_xact_commit;
  	PgStat_Counter n_xact_rollback;
  	PgStat_Counter n_blocks_fetched;
  	PgStat_Counter n_blocks_hit;
  	PgStat_Counter n_tuples_returned;
  	PgStat_Counter n_tuples_fetched;
  	PgStat_Counter n_tuples_inserted;
  	PgStat_Counter n_tuples_updated;
  	PgStat_Counter n_tuples_deleted;
  	TimestampTz last_autovac_time;
  	PgStat_Counter n_conflict_tablespace;
  	PgStat_Counter n_conflict_lock;
  	PgStat_Counter n_conflict_snapshot;
  	PgStat_Counter n_conflict_bufferpin;
  	PgStat_Counter n_conflict_startup_deadlock;
  	PgStat_Counter n_temp_files;
  	PgStat_Counter n_temp_bytes;
  	PgStat_Counter n_deadlocks;
  	PgStat_Counter n_checksum_failures;
  	TimestampTz last_checksum_failure;
  	PgStat_Counter n_block_read_time;	/* times in microseconds */
  	PgStat_Counter n_block_write_time;
  	PgStat_Counter n_sessions;
  	PgStat_Counter total_session_time;
  	PgStat_Counter total_active_time;
  	PgStat_Counter total_idle_in_xact_time;
  	PgStat_Counter n_sessions_abandoned;
  	PgStat_Counter n_sessions_fatal;
  	PgStat_Counter n_sessions_killed;
  
  	TimestampTz stat_reset_timestamp;
  	TimestampTz stats_timestamp;	/* time of db stats file update */
  
  	/*
  	 * tables and functions must be last in the struct, because we don't write
  	 * the pointers out to the stats file.
  	 */
  	HTAB	   *tables;
  	HTAB	   *functions;
  } PgStat_StatDBEntry;
  
  typedef struct PgStat_StatFuncEntry
  {
  	Oid			functionid;
  
  	PgStat_Counter f_numcalls;
  
  	PgStat_Counter f_total_time;	/* times in microseconds */
  	PgStat_Counter f_self_time;
  } PgStat_StatFuncEntry;
  
  typedef struct PgStat_GlobalStats
  {
  	TimestampTz stats_timestamp;	/* time of stats file update */
  
  	PgStat_CheckpointerStats checkpointer;
  	PgStat_BgWriterStats bgwriter;
  } PgStat_GlobalStats;
  
  typedef struct PgStat_StatReplSlotEntry
  {
  	NameData	slotname;
  	PgStat_Counter spill_txns;
  	PgStat_Counter spill_count;
  	PgStat_Counter spill_bytes;
  	PgStat_Counter stream_txns;
  	PgStat_Counter stream_count;
  	PgStat_Counter stream_bytes;
  	PgStat_Counter total_txns;
  	PgStat_Counter total_bytes;
  	TimestampTz stat_reset_timestamp;
  } PgStat_StatReplSlotEntry;
  
  typedef struct PgStat_SLRUStats
  {
  	PgStat_Counter blocks_zeroed;
  	PgStat_Counter blocks_hit;
  	PgStat_Counter blocks_read;
  	PgStat_Counter blocks_written;
  	PgStat_Counter blocks_exists;
  	PgStat_Counter flush;
  	PgStat_Counter truncate;
  	TimestampTz stat_reset_timestamp;
  } PgStat_SLRUStats;
  
  typedef struct PgStat_StatSubEntry
  {
  	Oid			subid;			/* hash key (must be first) */
  
  	PgStat_Counter apply_error_count;
  	PgStat_Counter sync_error_count;
  	TimestampTz stat_reset_timestamp;
  } PgStat_StatSubEntry;
  
  typedef struct PgStat_StatTabEntry
  {
  	Oid			tableid;
  
  	PgStat_Counter numscans;
  
  	PgStat_Counter tuples_returned;
  	PgStat_Counter tuples_fetched;
  
  	PgStat_Counter tuples_inserted;
  	PgStat_Counter tuples_updated;
  	PgStat_Counter tuples_deleted;
  	PgStat_Counter tuples_hot_updated;
  
  	PgStat_Counter n_live_tuples;
  	PgStat_Counter n_dead_tuples;
  	PgStat_Counter changes_since_analyze;
  	PgStat_Counter inserts_since_vacuum;
  
  	PgStat_Counter blocks_fetched;
  	PgStat_Counter blocks_hit;
  
  	TimestampTz vacuum_timestamp;	/* user initiated vacuum */
  	PgStat_Counter vacuum_count;
  	TimestampTz autovac_vacuum_timestamp;	/* autovacuum initiated */
  	PgStat_Counter autovac_vacuum_count;
  	TimestampTz analyze_timestamp;	/* user initiated */
  	PgStat_Counter analyze_count;
  	TimestampTz autovac_analyze_timestamp;	/* autovacuum initiated */
  	PgStat_Counter autovac_analyze_count;
  } PgStat_StatTabEntry;
  
  typedef struct PgStat_WalStats
  {
  	PgStat_Counter wal_records;
  	PgStat_Counter wal_fpi;
  	uint64		wal_bytes;
  	PgStat_Counter wal_buffers_full;
  	PgStat_Counter wal_write;
  	PgStat_Counter wal_sync;
  	PgStat_Counter wal_write_time;
  	PgStat_Counter wal_sync_time;
  	TimestampTz stat_reset_timestamp;
  } PgStat_WalStats;
  
  
  /*
   * Functions in pgstat.c
   */
  
  /* functions called from postmaster */
  extern void pgstat_init(void);
  extern void pgstat_reset_all(void);
  extern int	pgstat_start(void);
  extern void allow_immediate_pgstat_restart(void);
  
  #ifdef EXEC_BACKEND
  extern void PgstatCollectorMain(int argc, char *argv[]) pg_attribute_noreturn();
  #endif
  
  /* Functions for backend initialization */
  extern void pgstat_initialize(void);
  
  /* transactional integration */
  extern void AtEOXact_PgStat(bool isCommit, bool parallel);
  extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
  extern void AtPrepare_PgStat(void);
  extern void PostPrepare_PgStat(void);
  extern void pgstat_clear_snapshot(void);
  
  /* Functions called from backends */
  extern void pgstat_report_stat(bool force);
  extern void pgstat_vacuum_stat(void);
  extern void pgstat_ping(void);
  
  extern void pgstat_reset_counters(void);
  extern void pgstat_reset_single_counter(Oid objectid, PgStat_Single_Reset_Type type);
  extern void pgstat_reset_shared_counters(const char *);
  
  /* stats accessors */
  extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
  extern PgStat_BgWriterStats *pgstat_fetch_stat_bgwriter(void);
  extern PgStat_CheckpointerStats *pgstat_fetch_stat_checkpointer(void);
  extern PgStat_StatDBEntry *pgstat_fetch_stat_dbentry(Oid dbid);
  extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
  extern PgStat_GlobalStats *pgstat_fetch_global(void);
  extern PgStat_StatReplSlotEntry *pgstat_fetch_replslot(NameData slotname);
  extern PgStat_StatSubEntry *pgstat_fetch_stat_subscription(Oid subid);
  extern PgStat_SLRUStats *pgstat_fetch_slru(void);
  extern PgStat_StatTabEntry *pgstat_fetch_stat_tabentry(Oid relid);
  extern PgStat_WalStats *pgstat_fetch_stat_wal(void);
  
  
  /*
   * Functions in pgstat_archiver.c
   */
  
  extern void pgstat_send_archiver(const char *xlog, bool failed);
  
  
  /*
   * Functions in pgstat_bgwriter.c
   */
  
  extern void pgstat_send_bgwriter(void);
  
  
  /*
   * Functions in pgstat_checkpointer.c
   */
  
  extern void pgstat_send_checkpointer(void);
  
  
  /*
   * Functions in pgstat_database.c
   */
  
  extern void pgstat_drop_database(Oid databaseid);
  extern void pgstat_report_recovery_conflict(int reason);
  extern void pgstat_report_deadlock(void);
  extern void pgstat_report_checksum_failures_in_db(Oid dboid, int failurecount);
  extern void pgstat_report_checksum_failure(void);
  extern void pgstat_report_connect(Oid dboid);
  
  #define pgstat_count_buffer_read_time(n)							\
  	(pgStatBlockReadTime += (n))
  #define pgstat_count_buffer_write_time(n)							\
  	(pgStatBlockWriteTime += (n))
  #define pgstat_count_conn_active_time(n)							\
  	(pgStatActiveTime += (n))
  #define pgstat_count_conn_txn_idle_time(n)							\
  	(pgStatTransactionIdleTime += (n))
  
  
  /*
   * Functions in pgstat_function.c
   */
  
  struct FunctionCallInfoBaseData;
  extern void pgstat_init_function_usage(struct FunctionCallInfoBaseData *fcinfo,
  									   PgStat_FunctionCallUsage *fcu);
  extern void pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu,
  									  bool finalize);
  
  extern PgStat_BackendFunctionEntry *find_funcstat_entry(Oid func_id);
  
  
  /*
   * Functions in pgstat_relation.c
   */
  
  extern void pgstat_relation_init(Relation rel);
  
  extern void pgstat_report_autovac(Oid dboid);
  extern void pgstat_report_vacuum(Oid tableoid, bool shared,
  								 PgStat_Counter livetuples, PgStat_Counter deadtuples);
  extern void pgstat_report_analyze(Relation rel,
  								  PgStat_Counter livetuples, PgStat_Counter deadtuples,
  								  bool resetcounter);
  
  #define pgstat_relation_should_count(rel)                           \
  	(likely((rel)->pgstat_info != NULL))
  
  /* nontransactional event counts are simple enough to inline */
  
  #define pgstat_count_heap_scan(rel)									\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_numscans++;				\
  	} while (0)
  #define pgstat_count_heap_getnext(rel)								\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_tuples_returned++;		\
  	} while (0)
  #define pgstat_count_heap_fetch(rel)								\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_tuples_fetched++;		\
  	} while (0)
  #define pgstat_count_index_scan(rel)								\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_numscans++;				\
  	} while (0)
  #define pgstat_count_index_tuples(rel, n)							\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_tuples_returned += (n);	\
  	} while (0)
  #define pgstat_count_buffer_read(rel)								\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_blocks_fetched++;		\
  	} while (0)
  #define pgstat_count_buffer_hit(rel)								\
  	do {															\
  		if (pgstat_relation_should_count(rel))						\
  			(rel)->pgstat_info->t_counts.t_blocks_hit++;			\
  	} while (0)
  
  extern void pgstat_count_heap_insert(Relation rel, PgStat_Counter n);
  extern void pgstat_count_heap_update(Relation rel, bool hot);
  extern void pgstat_count_heap_delete(Relation rel);
  extern void pgstat_count_truncate(Relation rel);
  extern void pgstat_update_heap_dead_tuples(Relation rel, int delta);
  
  extern void pgstat_twophase_postcommit(TransactionId xid, uint16 info,
  									   void *recdata, uint32 len);
  extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
  									  void *recdata, uint32 len);
  
  extern PgStat_TableStatus *find_tabstat_entry(Oid rel_id);
  
  
  /*
   * Functions in pgstat_replslot.c
   */
  
  extern void pgstat_reset_replslot_counter(const char *name);
  extern void pgstat_report_replslot(const PgStat_StatReplSlotEntry *repSlotStat);
  extern void pgstat_report_replslot_create(const char *slotname);
  extern void pgstat_report_replslot_drop(const char *slotname);
  
  
  /*
   * Functions in pgstat_slru.c
   */
  
  extern void pgstat_reset_slru_counter(const char *);
  extern void pgstat_count_slru_page_zeroed(int slru_idx);
  extern void pgstat_count_slru_page_hit(int slru_idx);
  extern void pgstat_count_slru_page_read(int slru_idx);
  extern void pgstat_count_slru_page_written(int slru_idx);
  extern void pgstat_count_slru_page_exists(int slru_idx);
  extern void pgstat_count_slru_flush(int slru_idx);
  extern void pgstat_count_slru_truncate(int slru_idx);
  extern const char *pgstat_slru_name(int slru_idx);
  extern int	pgstat_slru_index(const char *name);
  
  
  /*
   * Functions in pgstat_subscription.c
   */
  
  extern void pgstat_reset_subscription_counter(Oid subid);
  extern void pgstat_report_subscription_error(Oid subid, bool is_apply_error);
  extern void pgstat_report_subscription_drop(Oid subid);
  
  
  /*
   * Functions in pgstat_wal.c
   */
  
  extern void pgstat_send_wal(bool force);
  
  
  /*
   * Variables in pgstat.c
   */
  
  /* GUC parameters */
  extern PGDLLIMPORT bool pgstat_track_counts;
  extern PGDLLIMPORT int pgstat_track_functions;
  extern char *pgstat_stat_directory;
  extern char *pgstat_stat_tmpname;
  extern char *pgstat_stat_filename;
  
  
  /*
   * Variables in pgstat_bgwriter.c
   */
  
  /* updated directly by bgwriter and bufmgr */
  extern PgStat_MsgBgWriter PendingBgWriterStats;
  
  
  /*
   * Variables in pgstat_checkpointer.c
   */
  
  /*
   * Checkpointer statistics counters are updated directly by checkpointer and
   * bufmgr.
   */
  extern PgStat_MsgCheckpointer PendingCheckpointerStats;
  
  
  /*
   * Variables in pgstat_database.c
   */
  
  /* Updated by pgstat_count_buffer_*_time macros */
  extern PgStat_Counter pgStatBlockReadTime;
  extern PgStat_Counter pgStatBlockWriteTime;
  
  /*
   * Updated by pgstat_count_conn_*_time macros, called by
   * pgstat_report_activity().
   */
  extern PgStat_Counter pgStatActiveTime;
  extern PgStat_Counter pgStatTransactionIdleTime;
  
  /* updated by the traffic cop and in errfinish() */
  extern SessionEndType pgStatSessionEndCause;
  
  
  /*
   * Variables in pgstat_wal.c
   */
  
  /* updated directly by backends and background processes */
  extern PgStat_MsgWal WalStats;
  
  
  #endif							/* PGSTAT_H */
  