globals.c

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/*-------------------------------------------------------------------------
 *
 * globals.c
 *    global variable declarations
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/init/globals.c
 *
 * NOTES
 *    Globals used all over the place should be declared here and not
 *    in other modules.
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"
 
#include "common/file_perm.h"
#include "libpq/libpq-be.h"
#include "libpq/pqcomm.h"
#include "miscadmin.h"
#include "postmaster/postmaster.h"
#include "storage/procnumber.h"
#include "storage/procsignal.h"
 
 
ProtocolVersion FrontendProtocol;
 
volatile sig_atomic_t InterruptPending = false;
volatile sig_atomic_t QueryCancelPending = false;
volatile sig_atomic_t ProcDiePending = false;
volatile sig_atomic_t CheckClientConnectionPending = false;
volatile sig_atomic_t ClientConnectionLost = false;
volatile sig_atomic_t IdleInTransactionSessionTimeoutPending = false;
volatile sig_atomic_t TransactionTimeoutPending = false;
volatile sig_atomic_t IdleSessionTimeoutPending = false;
volatile sig_atomic_t ProcSignalBarrierPending = false;
volatile sig_atomic_t LogMemoryContextPending = false;
volatile sig_atomic_t PublishMemoryContextPending = false;
volatile sig_atomic_t IdleStatsUpdateTimeoutPending = false;
volatile uint32 InterruptHoldoffCount = 0;
volatile uint32 QueryCancelHoldoffCount = 0;
volatile uint32 CritSectionCount = 0;
 
int         MyProcPid;
pg_time_t   MyStartTime;
TimestampTz MyStartTimestamp;
struct ClientSocket *MyClientSocket;
struct Port *MyProcPort;
char        MyCancelKey[MAX_CANCEL_KEY_LENGTH];
uint8       MyCancelKeyLength = 0;
int         MyPMChildSlot;
 
/*
 * MyLatch points to the latch that should be used for signal handling by the
 * current process. It will either point to a process local latch if the
 * current process does not have a PGPROC entry in that moment, or to
 * PGPROC->procLatch if it has. Thus it can always be used in signal handlers,
 * without checking for its existence.
 */
struct Latch *MyLatch;
 
/*
 * 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;
 
/*
 * Mode of the data directory.  The default is 0700 but it may be changed in
 * checkDataDir() to 0750 if the data directory actually has that mode.
 */
int         data_directory_mode = PG_DIR_MODE_OWNER;
 
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
 
ProcNumber  MyProcNumber = INVALID_PROC_NUMBER;
 
ProcNumber  ParallelLeaderProcNumber = INVALID_PROC_NUMBER;
 
Oid         MyDatabaseId = InvalidOid;
 
Oid         MyDatabaseTableSpace = InvalidOid;
 
bool        MyDatabaseHasLoginEventTriggers = false;
 
/*
 * 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        IsBinaryUpgrade = false;
 
bool        ExitOnAnyError = false;
 
int         DateStyle = USE_ISO_DATES;
int         DateOrder = DATEORDER_MDY;
int         IntervalStyle = INTSTYLE_POSTGRES;
 
bool        enableFsync = true;
bool        allowSystemTableMods = false;
int         work_mem = 4096;
double      hash_mem_multiplier = 2.0;
int         maintenance_work_mem = 65536;
int         max_parallel_maintenance_workers = 2;
 
/*
 * Primary determinants of sizes of shared-memory structures.
 *
 * MaxBackends is computed by PostmasterMain after modules have had a chance to
 * register background workers.
 */
int         NBuffers = 16384;
int         MaxConnections = 100;
int         max_worker_processes = 8;
int         max_parallel_workers = 8;
int         MaxBackends = 0;
 
/* GUC parameters for vacuum */
int         VacuumBufferUsageLimit = 2048;
 
int         VacuumCostPageHit = 1;
int         VacuumCostPageMiss = 2;
int         VacuumCostPageDirty = 20;
int         VacuumCostLimit = 200;
double      VacuumCostDelay = 0;
 
int         VacuumCostBalance = 0;  /* working state for vacuum */
bool        VacuumCostActive = false;
 
/* configurable SLRU buffer sizes */
int         commit_timestamp_buffers = 0;
int         multixact_member_buffers = 32;
int         multixact_offset_buffers = 16;
int         notify_buffers = 16;
int         serializable_buffers = 32;
int         subtransaction_buffers = 0;
int         transaction_buffers = 0;