globals.c

PostgreSQL 8.1.4的源码 适用于Linux下的开源数据库系统

/*-------------------------------------------------------------------------
 *
 * globals.c
 *	  global variable declarations
 *
 * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *	  $PostgreSQL: pgsql/src/backend/utils/init/globals.c,v 1.96 2005/07/04 04:51:50 tgl Exp $
 *
 * NOTES
 *	  Globals used all over the place should be declared here and not
 *	  in other modules.
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include "libpq/pqcomm.h"
#include "miscadmin.h"
#include "storage/backendid.h"


ProtocolVersion FrontendProtocol = PG_PROTOCOL_LATEST;

volatile bool InterruptPending = false;
volatile bool QueryCancelPending = false;
volatile bool ProcDiePending = false;
volatile bool ImmediateInterruptOK = false;
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 CritSectionCount = 0;

int			MyProcPid;
struct Port *MyProcPort;
long		MyCancelKey;

/*
 * DataDir is the absolute path to the top level of the PGDATA directory tree.
 * Except during early startup, this is also the server's working directory;
 * most code therefore can simply use relative paths and not reference DataDir
 * explicitly.
 */
char	   *DataDir = NULL;

char		OutputFileName[MAXPGPATH];	/* debugging output file */

char		my_exec_path[MAXPGPATH];	/* full path to my executable */
char		pkglib_path[MAXPGPATH];		/* full path to lib directory */

#ifdef EXEC_BACKEND
char		postgres_exec_path[MAXPGPATH];		/* full path to backend */

/* note: currently this is not valid in backend processes */
#endif

BackendId	MyBackendId = InvalidBackendId;

Oid			MyDatabaseId = InvalidOid;

Oid			MyDatabaseTableSpace = InvalidOid;

/*
 * DatabasePath is the path (relative to DataDir) of my database's
 * primary directory, ie, its directory in the default tablespace.
 */
char	   *DatabasePath = NULL;

pid_t		PostmasterPid = 0;

/*
 * IsPostmasterEnvironment is true in a postmaster process and any postmaster
 * child process; it is false in a standalone process (bootstrap or
 * standalone backend).  IsUnderPostmaster is true in postmaster child
 * processes.  Note that "child process" includes all children, not only
 * regular backends.  These should be set correctly as early as possible
 * in the execution of a process, so that error handling will do the right
 * things if an error should occur during process initialization.
 *
 * These are initialized for the bootstrap/standalone case.
 */
bool		IsPostmasterEnvironment = false;
bool		IsUnderPostmaster = false;

bool		ExitOnAnyError = false;

int			DateStyle = USE_ISO_DATES;
int			DateOrder = DATEORDER_MDY;
bool		HasCTZSet = false;
int			CTimeZone = 0;

bool		enableFsync = true;
bool		allowSystemTableMods = false;
int			work_mem = 1024;
int			maintenance_work_mem = 16384;

/* Primary determinants of sizes of shared-memory structures: */
int			NBuffers = 1000;
int			MaxBackends = 100;

int			VacuumCostPageHit = 1;		/* GUC parameters for vacuum */
int			VacuumCostPageMiss = 10;
int			VacuumCostPageDirty = 20;
int			VacuumCostLimit = 200;
int			VacuumCostDelay = 0;

int			VacuumCostBalance = 0;		/* working state for vacuum */
bool		VacuumCostActive = false;