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125 lines
3.9 KiB
C
125 lines
3.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* proc.h
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* per-process shared memory data structures
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*
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*
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* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/storage/proc.h,v 1.70 2004/07/21 20:23:04 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef _PROC_H_
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#define _PROC_H_
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#include "access/xlog.h"
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#include "storage/backendid.h"
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#include "storage/lock.h"
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#include "storage/pg_sema.h"
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/*
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* Each backend has a PGPROC struct in shared memory. There is also a list of
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* currently-unused PGPROC structs that will be reallocated to new backends.
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*
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* links: list link for any list the PGPROC is in. When waiting for a lock,
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* the PGPROC is linked into that lock's waitProcs queue. A recycled PGPROC
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* is linked into ProcGlobal's freeProcs list.
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*/
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struct PGPROC
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{
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/* proc->links MUST BE FIRST IN STRUCT (see ProcSleep,ProcWakeup,etc) */
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SHM_QUEUE links; /* list link if process is in a list */
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PGSemaphoreData sem; /* ONE semaphore to sleep on */
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int waitStatus; /* STATUS_OK or STATUS_ERROR after wakeup */
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TransactionId xid; /* transaction currently being executed by
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* this proc */
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TransactionId xmin; /* minimal running XID as it was when we
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* were starting our xact: vacuum must not
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* remove tuples deleted by xid >= xmin ! */
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int pid; /* This backend's process id */
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Oid databaseId; /* OID of database this backend is using */
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/*
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* XLOG location of first XLOG record written by this backend's
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* current transaction. If backend is not in a transaction or hasn't
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* yet modified anything, logRec.xrecoff is zero.
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*/
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XLogRecPtr logRec;
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/* Info about LWLock the process is currently waiting for, if any. */
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bool lwWaiting; /* true if waiting for an LW lock */
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bool lwExclusive; /* true if waiting for exclusive access */
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struct PGPROC *lwWaitLink; /* next waiter for same LW lock */
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/* Info about lock the process is currently waiting for, if any. */
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/* waitLock and waitHolder are NULL if not currently waiting. */
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LOCK *waitLock; /* Lock object we're sleeping on ... */
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PROCLOCK *waitHolder; /* Per-holder info for awaited lock */
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LOCKMODE waitLockMode; /* type of lock we're waiting for */
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LOCKMASK heldLocks; /* bitmask for lock types already held on
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* this lock object by this backend */
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SHM_QUEUE procHolders; /* list of PROCLOCK objects for locks held
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* or awaited by this backend */
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};
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/* NOTE: "typedef struct PGPROC PGPROC" appears in storage/lock.h. */
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extern DLLIMPORT PGPROC *MyProc;
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/*
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* There is one ProcGlobal struct for the whole installation.
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*/
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typedef struct PROC_HDR
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{
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/* Head of list of free PGPROC structures */
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SHMEM_OFFSET freeProcs;
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} PROC_HDR;
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#define DUMMY_PROC_DEFAULT 0
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#define DUMMY_PROC_BGWRITER 1
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#define DUMMY_PROC_AUTOVAC 2
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#define NUM_DUMMY_PROCS 3
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/* configurable options */
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extern int DeadlockTimeout;
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extern int StatementTimeout;
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/*
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* Function Prototypes
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*/
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extern int ProcGlobalSemas(int maxBackends);
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extern void InitProcGlobal(int maxBackends);
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extern void InitProcess(void);
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extern void InitDummyProcess(int proctype);
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extern void ProcReleaseLocks(bool isCommit);
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extern void ProcQueueInit(PROC_QUEUE *queue);
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extern int ProcSleep(LockMethod lockMethodTable, LOCKMODE lockmode,
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LOCK *lock, PROCLOCK *proclock);
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extern PGPROC *ProcWakeup(PGPROC *proc, int waitStatus);
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extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
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extern bool LockWaitCancel(void);
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extern void ProcWaitForSignal(void);
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extern void ProcCancelWaitForSignal(void);
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extern void ProcSendSignal(BackendId procId);
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extern bool enable_sig_alarm(int delayms, bool is_statement_timeout);
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extern bool disable_sig_alarm(bool is_statement_timeout);
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extern void handle_sig_alarm(SIGNAL_ARGS);
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#endif /* PROC_H */
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