e7ca867485
method control structure, or a table of control structures.
. Use type LOCKMASK where an int is not a counter.
. Get rid of INVALID_TABLEID, use INVALID_LOCKMETHOD instead.
. Use INVALID_LOCKMETHOD instead of (LOCKMETHOD) NULL, because
LOCKMETHOD is not a pointer.
. Define and use macro LockMethodIsValid.
. Rename LOCKMETHOD to LOCKMETHODID.
. Remove global variable LongTermTableId in lmgr.c, because it is
never used.
. Make LockTableId static in lmgr.c, because it is used nowhere else.
Why not remove it and use DEFAULT_LOCKMETHOD?
. Rename the lock method control structure from LOCKMETHODTABLE to
LockMethodData. Introduce a pointer type named LockMethod.
. Remove elog(FATAL) after InitLockTable() call in
CreateSharedMemoryAndSemaphores(), because if something goes wrong,
there is elog(FATAL) in LockMethodTableInit(), and if this doesn't
help, an elog(ERROR) in InitLockTable() is promoted to FATAL.
. Make InitLockTable() void, because its only caller does not use its
return value any more.
. Rename variables in lock.c to avoid statements like
LockMethodTable[NumLockMethods] = lockMethodTable;
lockMethodTable = LockMethodTable[lockmethod];
. Change LOCKMETHODID type to uint16 to fit into struct LOCKTAG.
. Remove static variables BITS_OFF and BITS_ON from lock.c, because
I agree to this doubt:
* XXX is a fetch from a static array really faster than a shift?
. Define and use macros LOCKBIT_ON/OFF.
Manfred Koizar
124 lines
3.9 KiB
C
124 lines
3.9 KiB
C
/*-------------------------------------------------------------------------
|
|
*
|
|
* proc.h
|
|
* per-process shared memory data structures
|
|
*
|
|
*
|
|
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
|
|
* Portions Copyright (c) 1994, Regents of the University of California
|
|
*
|
|
* $PostgreSQL: pgsql/src/include/storage/proc.h,v 1.67 2003/12/01 21:59:25 momjian Exp $
|
|
*
|
|
*-------------------------------------------------------------------------
|
|
*/
|
|
#ifndef _PROC_H_
|
|
#define _PROC_H_
|
|
|
|
#include "access/xlog.h"
|
|
#include "storage/backendid.h"
|
|
#include "storage/lock.h"
|
|
#include "storage/pg_sema.h"
|
|
|
|
|
|
/*
|
|
* Each backend has a PGPROC struct in shared memory. There is also a list of
|
|
* currently-unused PGPROC structs that will be reallocated to new backends.
|
|
*
|
|
* links: list link for any list the PGPROC is in. When waiting for a lock,
|
|
* the PGPROC is linked into that lock's waitProcs queue. A recycled PGPROC
|
|
* is linked into ProcGlobal's freeProcs list.
|
|
*/
|
|
struct PGPROC
|
|
{
|
|
/* proc->links MUST BE FIRST IN STRUCT (see ProcSleep,ProcWakeup,etc) */
|
|
SHM_QUEUE links; /* list link if process is in a list */
|
|
|
|
PGSemaphoreData sem; /* ONE semaphore to sleep on */
|
|
int errType; /* STATUS_OK or STATUS_ERROR after wakeup */
|
|
|
|
TransactionId xid; /* transaction currently being executed by
|
|
* this proc */
|
|
|
|
TransactionId xmin; /* minimal running XID as it was when we
|
|
* were starting our xact: vacuum must not
|
|
* remove tuples deleted by xid >= xmin ! */
|
|
|
|
int pid; /* This backend's process id */
|
|
Oid databaseId; /* OID of database this backend is using */
|
|
|
|
/*
|
|
* XLOG location of first XLOG record written by this backend's
|
|
* current transaction. If backend is not in a transaction or hasn't
|
|
* yet modified anything, logRec.xrecoff is zero.
|
|
*/
|
|
XLogRecPtr logRec;
|
|
|
|
/* Info about LWLock the process is currently waiting for, if any. */
|
|
bool lwWaiting; /* true if waiting for an LW lock */
|
|
bool lwExclusive; /* true if waiting for exclusive access */
|
|
struct PGPROC *lwWaitLink; /* next waiter for same LW lock */
|
|
|
|
/* Info about lock the process is currently waiting for, if any. */
|
|
/* waitLock and waitHolder are NULL if not currently waiting. */
|
|
LOCK *waitLock; /* Lock object we're sleeping on ... */
|
|
PROCLOCK *waitHolder; /* Per-holder info for awaited lock */
|
|
LOCKMODE waitLockMode; /* type of lock we're waiting for */
|
|
LOCKMASK heldLocks; /* bitmask for lock types already held on
|
|
* this lock object by this backend */
|
|
|
|
SHM_QUEUE procHolders; /* list of PROCLOCK objects for locks held
|
|
* or awaited by this backend */
|
|
};
|
|
|
|
/* NOTE: "typedef struct PGPROC PGPROC" appears in storage/lock.h. */
|
|
|
|
|
|
extern DLLIMPORT PGPROC *MyProc;
|
|
|
|
|
|
/*
|
|
* There is one ProcGlobal struct for the whole installation.
|
|
*/
|
|
typedef struct PROC_HDR
|
|
{
|
|
/* Head of list of free PGPROC structures */
|
|
SHMEM_OFFSET freeProcs;
|
|
} PROC_HDR;
|
|
|
|
|
|
#define DUMMY_PROC_DEFAULT 0
|
|
#define DUMMY_PROC_BGWRITER 1
|
|
#define NUM_DUMMY_PROCS 2
|
|
|
|
|
|
/* configurable options */
|
|
extern int DeadlockTimeout;
|
|
extern int StatementTimeout;
|
|
|
|
|
|
/*
|
|
* Function Prototypes
|
|
*/
|
|
extern int ProcGlobalSemas(int maxBackends);
|
|
extern void InitProcGlobal(int maxBackends);
|
|
extern void InitProcess(void);
|
|
extern void InitDummyProcess(int proctype);
|
|
extern void ProcReleaseLocks(bool isCommit);
|
|
|
|
extern void ProcQueueInit(PROC_QUEUE *queue);
|
|
extern int ProcSleep(LockMethod lockMethodTable, LOCKMODE lockmode,
|
|
LOCK *lock, PROCLOCK *proclock);
|
|
extern PGPROC *ProcWakeup(PGPROC *proc, int errType);
|
|
extern void ProcLockWakeup(LockMethod lockMethodTable, LOCK *lock);
|
|
extern bool LockWaitCancel(void);
|
|
|
|
extern void ProcWaitForSignal(void);
|
|
extern void ProcCancelWaitForSignal(void);
|
|
extern void ProcSendSignal(BackendId procId);
|
|
|
|
extern bool enable_sig_alarm(int delayms, bool is_statement_timeout);
|
|
extern bool disable_sig_alarm(bool is_statement_timeout);
|
|
extern void handle_sig_alarm(SIGNAL_ARGS);
|
|
|
|
#endif /* PROC_H */
|