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Try to reduce confusion about what is a lock method identifier, a lock

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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
This commit is contained in:
Bruce Momjian
2003-12-01 21:59:25 +00:00
parent e2ac58c7bd
commit e7ca867485
8 changed files with 153 additions and 181 deletions
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27
src/backend/storage/lmgr/lmgr.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.61 2003/11/29 19:51:56 pgsql Exp $
* $PostgreSQL: pgsql/src/backend/storage/lmgr/lmgr.c,v 1.62 2003/12/01 21:59:25 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -65,26 +65,24 @@ static LOCKMASK LockConflicts[] = {
};
LOCKMETHOD LockTableId = (LOCKMETHOD) NULL;
LOCKMETHOD LongTermTableId = (LOCKMETHOD) NULL;
static LOCKMETHODID LockTableId = INVALID_LOCKMETHOD;
/*
* Create the lock table described by LockConflicts
*/
LOCKMETHOD
void
InitLockTable(int maxBackends)
{
int lockmethod;
LOCKMETHODID LongTermTableId;
/* number of lock modes is lengthof()-1 because of dummy zero */
lockmethod = LockMethodTableInit("LockTable",
LockConflicts,
lengthof(LockConflicts) - 1,
maxBackends);
LockTableId = lockmethod;
if (!(LockTableId))
LockTableId = LockMethodTableInit("LockTable",
LockConflicts,
lengthof(LockConflicts) - 1,
maxBackends);
if (!LockMethodIsValid(LockTableId))
elog(ERROR, "could not initialize lock table");
Assert(LockTableId == DEFAULT_LOCKMETHOD);
#ifdef USER_LOCKS
@@ -92,11 +90,10 @@ InitLockTable(int maxBackends)
* Allocate another tableId for long-term locks
*/
LongTermTableId = LockMethodTableRename(LockTableId);
if (!(LongTermTableId))
if (!LockMethodIsValid(LongTermTableId))
elog(ERROR, "could not rename long-term lock table");
Assert(LongTermTableId == USER_LOCKMETHOD);
#endif
return LockTableId;
}
/*