text: /*-------------------------------------------------------------------------
   *
   * procarray.h
   *	  POSTGRES process array definitions.
   *
   *
   * Portions Copyright (c) 1996-2019, PostgreSQL Global Development Group
   * Portions Copyright (c) 1994, Regents of the University of California
   *
   * src/include/storage/procarray.h
   *
   *-------------------------------------------------------------------------
   */
  #ifndef PROCARRAY_H
  #define PROCARRAY_H
  
  #include "storage/lock.h"
  #include "storage/standby.h"
  #include "utils/relcache.h"
  #include "utils/snapshot.h"
  
  
  /*
   * These are to implement PROCARRAY_FLAGS_XXX
   *
   * Note: These flags are cloned from PROC_XXX flags in src/include/storage/proc.h
   * to avoid forcing to include proc.h when including procarray.h. So if you modify
   * PROC_XXX flags, you need to modify these flags.
   */
  #define		PROCARRAY_VACUUM_FLAG			0x02	/* currently running lazy
  													 * vacuum */
  #define		PROCARRAY_ANALYZE_FLAG			0x04	/* currently running
  													 * analyze */
  #define		PROCARRAY_LOGICAL_DECODING_FLAG 0x10	/* currently doing logical
  													 * decoding outside xact */
  
  #define		PROCARRAY_SLOTS_XMIN			0x20	/* replication slot xmin,
  													 * catalog_xmin */
  /*
   * Only flags in PROCARRAY_PROC_FLAGS_MASK are considered when matching
   * PGXACT->vacuumFlags. Other flags are used for different purposes and
   * have no corresponding PROC flag equivalent.
   */
  #define		PROCARRAY_PROC_FLAGS_MASK	(PROCARRAY_VACUUM_FLAG | \
  										 PROCARRAY_ANALYZE_FLAG | \
  										 PROCARRAY_LOGICAL_DECODING_FLAG)
  
  /* Use the following flags as an input "flags" to GetOldestXmin function */
  /* Consider all backends except for logical decoding ones which manage xmin separately */
  #define		PROCARRAY_FLAGS_DEFAULT			PROCARRAY_LOGICAL_DECODING_FLAG
  /* Ignore vacuum backends */
  #define		PROCARRAY_FLAGS_VACUUM			PROCARRAY_FLAGS_DEFAULT | PROCARRAY_VACUUM_FLAG
  /* Ignore analyze backends */
  #define		PROCARRAY_FLAGS_ANALYZE			PROCARRAY_FLAGS_DEFAULT | PROCARRAY_ANALYZE_FLAG
  /* Ignore both vacuum and analyze backends */
  #define		PROCARRAY_FLAGS_VACUUM_ANALYZE	PROCARRAY_FLAGS_DEFAULT | PROCARRAY_VACUUM_FLAG | PROCARRAY_ANALYZE_FLAG
  
  extern Size ProcArrayShmemSize(void);
  extern void CreateSharedProcArray(void);
  extern void ProcArrayAdd(PGPROC *proc);
  extern void ProcArrayRemove(PGPROC *proc, TransactionId latestXid);
  
  extern void ProcArrayEndTransaction(PGPROC *proc, TransactionId latestXid);
  extern void ProcArrayClearTransaction(PGPROC *proc);
  
  extern void ProcArrayInitRecovery(TransactionId initializedUptoXID);
  extern void ProcArrayApplyRecoveryInfo(RunningTransactions running);
  extern void ProcArrayApplyXidAssignment(TransactionId topxid,
  										int nsubxids, TransactionId *subxids);
  
  extern void RecordKnownAssignedTransactionIds(TransactionId xid);
  extern void ExpireTreeKnownAssignedTransactionIds(TransactionId xid,
  												  int nsubxids, TransactionId *subxids,
  												  TransactionId max_xid);
  extern void ExpireAllKnownAssignedTransactionIds(void);
  extern void ExpireOldKnownAssignedTransactionIds(TransactionId xid);
  
  extern int	GetMaxSnapshotXidCount(void);
  extern int	GetMaxSnapshotSubxidCount(void);
  
  extern Snapshot GetSnapshotData(Snapshot snapshot);
  
  extern bool ProcArrayInstallImportedXmin(TransactionId xmin,
  										 VirtualTransactionId *sourcevxid);
  extern bool ProcArrayInstallRestoredXmin(TransactionId xmin, PGPROC *proc);
  
  extern RunningTransactions GetRunningTransactionData(void);
  
  extern bool TransactionIdIsInProgress(TransactionId xid);
  extern bool TransactionIdIsActive(TransactionId xid);
  extern TransactionId GetOldestXmin(Relation rel, int flags);
  extern TransactionId GetOldestActiveTransactionId(void);
  extern TransactionId GetOldestSafeDecodingTransactionId(bool catalogOnly);
  
  extern VirtualTransactionId *GetVirtualXIDsDelayingChkpt(int *nvxids);
  extern bool HaveVirtualXIDsDelayingChkpt(VirtualTransactionId *vxids, int nvxids);
  
  extern PGPROC *BackendPidGetProc(int pid);
  extern PGPROC *BackendPidGetProcWithLock(int pid);
  extern int	BackendXidGetPid(TransactionId xid);
  extern bool IsBackendPid(int pid);
  
  extern VirtualTransactionId *GetCurrentVirtualXIDs(TransactionId limitXmin,
  												   bool excludeXmin0, bool allDbs, int excludeVacuum,
  												   int *nvxids);
  extern VirtualTransactionId *GetConflictingVirtualXIDs(TransactionId limitXmin, Oid dbOid);
  extern pid_t CancelVirtualTransaction(VirtualTransactionId vxid, ProcSignalReason sigmode);
  extern pid_t SignalVirtualTransaction(VirtualTransactionId vxid, ProcSignalReason sigmode,
  									  bool conflictPending);
  
  extern bool MinimumActiveBackends(int min);
  extern int	CountDBBackends(Oid databaseid);
  extern int	CountDBConnections(Oid databaseid);
  extern void CancelDBBackends(Oid databaseid, ProcSignalReason sigmode, bool conflictPending);
  extern int	CountUserBackends(Oid roleid);
  extern bool CountOtherDBBackends(Oid databaseId,
  								 int *nbackends, int *nprepared);
  
  extern void XidCacheRemoveRunningXids(TransactionId xid,
  									  int nxids, const TransactionId *xids,
  									  TransactionId latestXid);
  
  extern void ProcArraySetReplicationSlotXmin(TransactionId xmin,
  											TransactionId catalog_xmin, bool already_locked);
  
  extern void ProcArrayGetReplicationSlotXmin(TransactionId *xmin,
  											TransactionId *catalog_xmin);
  
  #endif							/* PROCARRAY_H */
  