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More comment improvements.

This commit is contained in:
Bruce Momjian 2001-02-22 23:02:33 +00:00
parent 4f6c49fef0
commit 82fc51e0b3
4 changed files with 102 additions and 101 deletions
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178
src/backend/storage/lmgr/lock.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.81 2001/01/25 03:31:16 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lock.c,v 1.82 2001/02/22 23:02:33 momjian Exp $
*
* NOTES
* Outside modules can create a lock table and acquire/release
@ -87,11 +87,11 @@ bool Debug_deadlocks = false;
inline static bool
LOCK_DEBUG_ENABLED(const LOCK * lock)
{
return
(((LOCK_LOCKMETHOD(*lock) == DEFAULT_LOCKMETHOD && Trace_locks)
|| (LOCK_LOCKMETHOD(*lock) == USER_LOCKMETHOD && Trace_userlocks))
&& (lock->tag.relId >= (Oid) Trace_lock_oidmin))
|| (Trace_lock_table && (lock->tag.relId == Trace_lock_table));
return
(((LOCK_LOCKMETHOD(*lock) == DEFAULT_LOCKMETHOD && Trace_locks)
|| (LOCK_LOCKMETHOD(*lock) == USER_LOCKMETHOD && Trace_userlocks))
&& (lock->tag.relId >= (Oid) Trace_lock_oidmin))
|| (Trace_lock_table && (lock->tag.relId == Trace_lock_table));
}
@ -99,20 +99,20 @@ inline static void
LOCK_PRINT(const char * where, const LOCK * lock, LOCKMODE type)
{
if (LOCK_DEBUG_ENABLED(lock))
elog(DEBUG,
"%s: lock(%lx) tbl(%d) rel(%u) db(%u) obj(%u) grantMask(%x) "
"req(%d,%d,%d,%d,%d,%d,%d)=%d "
"grant(%d,%d,%d,%d,%d,%d,%d)=%d wait(%d) type(%s)",
where, MAKE_OFFSET(lock),
lock->tag.lockmethod, lock->tag.relId, lock->tag.dbId,
lock->tag.objId.blkno, lock->grantMask,
lock->requested[1], lock->requested[2], lock->requested[3],
elog(DEBUG,
"%s: lock(%lx) tbl(%d) rel(%u) db(%u) obj(%u) grantMask(%x) "
"req(%d,%d,%d,%d,%d,%d,%d)=%d "
"grant(%d,%d,%d,%d,%d,%d,%d)=%d wait(%d) type(%s)",
where, MAKE_OFFSET(lock),
lock->tag.lockmethod, lock->tag.relId, lock->tag.dbId,
lock->tag.objId.blkno, lock->grantMask,
lock->requested[1], lock->requested[2], lock->requested[3],
lock->requested[4], lock->requested[5], lock->requested[6],
lock->requested[7], lock->nRequested,
lock->granted[1], lock->granted[2], lock->granted[3],
lock->granted[4], lock->granted[5], lock->granted[6],
lock->granted[7], lock->nGranted,
lock->waitProcs.size, lock_types[type]);
lock->granted[1], lock->granted[2], lock->granted[3],
lock->granted[4], lock->granted[5], lock->granted[6],
lock->granted[7], lock->nGranted,
lock->waitProcs.size, lock_types[type]);
}
@ -120,17 +120,17 @@ inline static void
HOLDER_PRINT(const char * where, const HOLDER * holderP)
{
if (
(((HOLDER_LOCKMETHOD(*holderP) == DEFAULT_LOCKMETHOD && Trace_locks)
|| (HOLDER_LOCKMETHOD(*holderP) == USER_LOCKMETHOD && Trace_userlocks))
&& (((LOCK *)MAKE_PTR(holderP->tag.lock))->tag.relId >= (Oid) Trace_lock_oidmin))
(((HOLDER_LOCKMETHOD(*holderP) == DEFAULT_LOCKMETHOD && Trace_locks)
|| (HOLDER_LOCKMETHOD(*holderP) == USER_LOCKMETHOD && Trace_userlocks))
&& (((LOCK *)MAKE_PTR(holderP->tag.lock))->tag.relId >= (Oid) Trace_lock_oidmin))
|| (Trace_lock_table && (((LOCK *)MAKE_PTR(holderP->tag.lock))->tag.relId == Trace_lock_table))
)
elog(DEBUG,
"%s: holder(%lx) lock(%lx) tbl(%d) proc(%lx) xid(%u) hold(%d,%d,%d,%d,%d,%d,%d)=%d",
where, MAKE_OFFSET(holderP), holderP->tag.lock,
)
elog(DEBUG,
"%s: holder(%lx) lock(%lx) tbl(%d) proc(%lx) xid(%u) hold(%d,%d,%d,%d,%d,%d,%d)=%d",
where, MAKE_OFFSET(holderP), holderP->tag.lock,
HOLDER_LOCKMETHOD(*(holderP)),
holderP->tag.proc, holderP->tag.xid,
holderP->holding[1], holderP->holding[2], holderP->holding[3],
holderP->tag.proc, holderP->tag.xid,
holderP->holding[1], holderP->holding[2], holderP->holding[3],
holderP->holding[4], holderP->holding[5], holderP->holding[6],
holderP->holding[7], holderP->nHolding);
}
@ -157,24 +157,24 @@ SPINLOCK LockMgrLock; /* in Shmem or created in
static LOCKMASK BITS_OFF[MAX_LOCKMODES];
static LOCKMASK BITS_ON[MAX_LOCKMODES];
/* -----------------
/*
* Disable flag
* -----------------
*
*/
static bool LockingIsDisabled;
/* -------------------
/*
* map from lockmethod to the lock table structure
* -------------------
*
*/
static LOCKMETHODTABLE *LockMethodTable[MAX_LOCK_METHODS];
static int NumLockMethods;
/* -------------------
/*
* InitLocks -- Init the lock module. Create a private data
* structure for constructing conflict masks.
* -------------------
*
*/
void
InitLocks(void)
@ -190,9 +190,9 @@ InitLocks(void)
}
}
/* -------------------
/*
* LockDisable -- sets LockingIsDisabled flag to TRUE or FALSE.
* ------------------
*
*/
void
LockDisable(bool status)
@ -200,9 +200,9 @@ LockDisable(bool status)
LockingIsDisabled = status;
}
/* -----------------
/*
* Boolean function to determine current locking status
* -----------------
*
*/
bool
LockingDisabled(void)
@ -295,16 +295,16 @@ LockMethodTableInit(char *tabName,
lockMethodTable = (LOCKMETHODTABLE *)
MemoryContextAlloc(TopMemoryContext, sizeof(LOCKMETHODTABLE));
/* ------------------------
/*
* find/acquire the spinlock for the table
* ------------------------
*
*/
SpinAcquire(LockMgrLock);
/* -----------------------
/*
* allocate a control structure from shared memory or attach to it
* if it already exists.
* -----------------------
*
*/
sprintf(shmemName, "%s (ctl)", tabName);
lockMethodTable->ctl = (LOCKMETHODCTL *)
@ -313,15 +313,15 @@ LockMethodTableInit(char *tabName,
if (!lockMethodTable->ctl)
elog(FATAL, "LockMethodTableInit: couldn't initialize %s", tabName);
/* -------------------
/*
* no zero-th table
* -------------------
*
*/
NumLockMethods = 1;
/* ----------------
/*
* we're first - initialize
* ----------------
*
*/
if (!found)
{
@ -330,18 +330,18 @@ LockMethodTableInit(char *tabName,
lockMethodTable->ctl->lockmethod = NumLockMethods;
}
/* --------------------
/*
* other modules refer to the lock table by a lockmethod ID
* --------------------
*
*/
LockMethodTable[NumLockMethods] = lockMethodTable;
NumLockMethods++;
Assert(NumLockMethods <= MAX_LOCK_METHODS);
/* ----------------------
/*
* allocate a hash table for LOCK structs. This is used
* to store per-locked-object information.
* ----------------------
*
*/
info.keysize = SHMEM_LOCKTAB_KEYSIZE;
info.datasize = SHMEM_LOCKTAB_DATASIZE;
@ -359,10 +359,10 @@ LockMethodTableInit(char *tabName,
elog(FATAL, "LockMethodTableInit: couldn't initialize %s", tabName);
Assert(lockMethodTable->lockHash->hash == tag_hash);
/* -------------------------
/*
* allocate a hash table for HOLDER structs. This is used
* to store per-lock-holder information.
* -------------------------
*
*/
info.keysize = SHMEM_HOLDERTAB_KEYSIZE;
info.datasize = SHMEM_HOLDERTAB_DATASIZE;
@ -528,9 +528,9 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
return FALSE;
}
/* --------------------
/*
* if it's a new lock object, initialize it
* --------------------
*
*/
if (!found)
{
@ -552,9 +552,9 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
Assert(lock->nGranted <= lock->nRequested);
}
/* ------------------
/*
* Create the hash key for the holder table.
* ------------------
*
*/
MemSet(&holdertag, 0, sizeof(HOLDERTAG)); /* must clear padding, needed */
holdertag.lock = MAKE_OFFSET(lock);
@ -623,20 +623,20 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
#endif /* CHECK_DEADLOCK_RISK */
}
/* ----------------
/*
* lock->nRequested and lock->requested[] count the total number of
* requests, whether granted or waiting, so increment those immediately.
* The other counts don't increment till we get the lock.
* ----------------
*
*/
lock->nRequested++;
lock->requested[lockmode]++;
Assert((lock->nRequested > 0) && (lock->requested[lockmode] > 0));
/* --------------------
/*
* If I already hold one or more locks of the requested type,
* just grant myself another one without blocking.
* --------------------
*
*/
if (holder->holding[lockmode] > 0)
{
@ -646,10 +646,10 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
return TRUE;
}
/* --------------------
/*
* If this process (under any XID) is a holder of the lock,
* also grant myself another one without blocking.
* --------------------
*
*/
LockCountMyLocks(holder->tag.lock, MyProc, myHolding);
if (myHolding[lockmode] > 0)
@ -660,11 +660,11 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
return TRUE;
}
/* --------------------
/*
* If lock requested conflicts with locks requested by waiters,
* must join wait queue. Otherwise, check for conflict with
* already-held locks. (That's last because most complex check.)
* --------------------
*
*/
if (lockMethodTable->ctl->conflictTab[lockmode] & lock->waitMask)
status = STATUS_FOUND;
@ -760,7 +760,7 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
return status == STATUS_OK;
}
/* ----------------------------
/*
* LockCheckConflicts -- test whether requested lock conflicts
* with those already granted
*
@ -775,7 +775,7 @@ LockAcquire(LOCKMETHOD lockmethod, LOCKTAG *locktag,
*
* The caller can optionally pass the process's total holding counts, if
* known. If NULL is passed then these values will be computed internally.
* ----------------------------
*
*/
int
LockCheckConflicts(LOCKMETHODTABLE *lockMethodTable,
@ -792,7 +792,7 @@ LockCheckConflicts(LOCKMETHODTABLE *lockMethodTable,
tmpMask;
int localHolding[MAX_LOCKMODES];
/* ----------------------------
/*
* first check for global conflicts: If no locks conflict
* with my request, then I get the lock.
*
@ -800,7 +800,7 @@ LockCheckConflicts(LOCKMETHODTABLE *lockMethodTable,
* currently held locks. conflictTable[lockmode] has a bit
* set for each type of lock that conflicts with request. Bitwise
* compare tells if there is a conflict.
* ----------------------------
*
*/
if (!(lockctl->conflictTab[lockmode] & lock->grantMask))
{
@ -808,12 +808,12 @@ LockCheckConflicts(LOCKMETHODTABLE *lockMethodTable,
return STATUS_OK;
}
/* ------------------------
/*
* Rats. Something conflicts. But it could still be my own
* lock. We have to construct a conflict mask
* that does not reflect our own locks. Locks held by the current
* process under another XID also count as "our own locks".
* ------------------------
*
*/
if (myHolding == NULL)
{
@ -831,12 +831,12 @@ LockCheckConflicts(LOCKMETHODTABLE *lockMethodTable,
bitmask |= tmpMask;
}
/* ------------------------
/*
* now check again for conflicts. 'bitmask' describes the types
* of locks held by other processes. If one of these
* conflicts with the kind of lock that I want, there is a
* conflict and I have to sleep.
* ------------------------
*
*/
if (!(lockctl->conflictTab[lockmode] & bitmask))
{
@ -935,7 +935,7 @@ WaitOnLock(LOCKMETHOD lockmethod, LOCKMODE lockmode,
strcat(new_status, " waiting");
set_ps_display(new_status);
/* -------------------
/*
* NOTE: Think not to put any lock state cleanup after the call to
* ProcSleep, in either the normal or failure path. The lock state
* must be fully set by the lock grantor, or by HandleDeadLock if we
@ -944,7 +944,7 @@ WaitOnLock(LOCKMETHOD lockmethod, LOCKMODE lockmode,
* after someone else grants us the lock, but before we've noticed it.
* Hence, after granting, the locktable state must fully reflect the
* fact that we own the lock; we can't do additional work on return.
* -------------------
*
*/
if (ProcSleep(lockMethodTable,
@ -952,11 +952,11 @@ WaitOnLock(LOCKMETHOD lockmethod, LOCKMODE lockmode,
lock,
holder) != STATUS_OK)
{
/* -------------------
/*
* We failed as a result of a deadlock, see HandleDeadLock().
* Quit now. Removal of the holder and lock objects, if no longer
* needed, will happen in xact cleanup (see above for motivation).
* -------------------
*
*/
LOCK_PRINT("WaitOnLock: aborting on lock", lock, lockmode);
SpinRelease(lockMethodTable->ctl->masterLock);
@ -1043,7 +1043,7 @@ LockRelease(LOCKMETHOD lockmethod, LOCKTAG *locktag,
#ifdef LOCK_DEBUG
if (lockmethod == USER_LOCKMETHOD && Trace_userlocks)
elog(DEBUG, "LockRelease: user lock tag [%u] %d", locktag->objId.blkno, lockmode);
elog(DEBUG, "LockRelease: user lock tag [%u] %d", locktag->objId.blkno, lockmode);
#endif
/* ???????? This must be changed when short term locks will be used */
@ -1105,7 +1105,7 @@ LockRelease(LOCKMETHOD lockmethod, LOCKTAG *locktag,
SpinRelease(masterLock);
#ifdef USER_LOCKS
if (!found && lockmethod == USER_LOCKMETHOD)
elog(NOTICE, "LockRelease: no lock with this tag");
elog(NOTICE, "LockRelease: no lock with this tag");
else
#endif
elog(NOTICE, "LockRelease: holder table corrupted");
@ -1150,7 +1150,7 @@ LockRelease(LOCKMETHOD lockmethod, LOCKTAG *locktag,
Assert((lock->nGranted >= 0) && (lock->granted[lockmode] >= 0));
Assert(lock->nGranted <= lock->nRequested);
/* --------------------------
/*
* We need only run ProcLockWakeup if the released lock conflicts with
* at least one of the lock types requested by waiter(s). Otherwise
* whatever conflict made them wait must still exist. NOTE: before MVCC,
@ -1158,18 +1158,18 @@ LockRelease(LOCKMETHOD lockmethod, LOCKTAG *locktag,
* But that's not true anymore, because the remaining granted locks might
* belong to some waiter, who could now be awakened because he doesn't
* conflict with his own locks.
* --------------------------
*
*/
if (lockMethodTable->ctl->conflictTab[lockmode] & lock->waitMask)
wakeupNeeded = true;
if (lock->nRequested == 0)
{
/* ------------------
/*
* if there's no one waiting in the queue,
* we just released the last lock on this object.
* Delete it from the lock table.
* ------------------
*
*/
Assert(lockMethodTable->lockHash->hash == tag_hash);
lock = (LOCK *) hash_search(lockMethodTable->lockHash,
@ -1297,9 +1297,9 @@ LockReleaseAll(LOCKMETHOD lockmethod, PROC *proc,
Assert(holder->nHolding >= 0);
Assert(holder->nHolding <= lock->nRequested);
/* ------------------
/*
* fix the general lock stats
* ------------------
*
*/
if (lock->nRequested != holder->nHolding)
{
@ -1328,10 +1328,10 @@ LockReleaseAll(LOCKMETHOD lockmethod, PROC *proc,
}
else
{
/* --------------
/*
* This holder accounts for all the requested locks on the object,
* so we can be lazy and just zero things out.
* --------------
*
*/
lock->nRequested = 0;
lock->nGranted = 0;
@ -1368,10 +1368,10 @@ LockReleaseAll(LOCKMETHOD lockmethod, PROC *proc,
if (lock->nRequested == 0)
{
/* --------------------
/*
* We've just released the last lock, so garbage-collect the
* lock object.
* --------------------
*
*/
LOCK_PRINT("LockReleaseAll: deleting", lock, 0);
Assert(lockMethodTable->lockHash->hash == tag_hash);
@ -1395,8 +1395,8 @@ next_item:
SpinRelease(masterLock);
#ifdef LOCK_DEBUG
if (lockmethod == USER_LOCKMETHOD ? Trace_userlocks : Trace_locks)
elog(DEBUG, "LockReleaseAll: done");
if (lockmethod == USER_LOCKMETHOD ? Trace_userlocks : Trace_locks)
elog(DEBUG, "LockReleaseAll: done");
#endif
return TRUE;

8
src/include/access/nbtree.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: nbtree.h,v 1.53 2001/02/22 21:48:49 momjian Exp $
* $Id: nbtree.h,v 1.54 2001/02/22 23:02:33 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -67,7 +67,7 @@ typedef struct BTMetaPageData
#define BTPageGetMeta(p) \
((BTMetaPageData *) &((PageHeader) p)->pd_linp[0])
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_METAPAGE 0 /* first page is meta */
#define BTREE_MAGIC 0x053162 /* magic number of btree pages */
#define BTreeInvalidParent(opaque) \
@ -215,8 +215,8 @@ typedef BTStackData *BTStack;
* items beginning in item 1.
*/
#define P_HIKEY ((OffsetNumber) 1)
#define P_FIRSTKEY ((OffsetNumber) 2)
#define P_HIKEY ((OffsetNumber) 1)
#define P_FIRSTKEY ((OffsetNumber) 2)
#define P_FIRSTDATAKEY(opaque) (P_RIGHTMOST(opaque) ? P_HIKEY : P_FIRSTKEY)
/*

13
src/include/storage/lmgr.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: lmgr.h,v 1.28 2001/01/24 19:43:27 momjian Exp $
* $Id: lmgr.h,v 1.29 2001/02/22 23:02:33 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -25,11 +25,12 @@
#define AccessShareLock 1 /* SELECT */
#define RowShareLock 2 /* SELECT FOR UPDATE */
#define RowExclusiveLock 3 /* INSERT, UPDATE, DELETE */
#define ShareLock 4
#define ShareRowExclusiveLock 5
#define ExclusiveLock 6
#define AccessExclusiveLock 7
#define ShareLock 4 /* CREATE INDEX */
#define ShareRowExclusiveLock 5 /* like EXCLUSIVE MODE, allows SHARE ROW */
#define ExclusiveLock 6 /* blocks ROW SHARE/SELECT...FOR UPDATE */
#define AccessExclusiveLock 7 /* ALTER TABLE, DROP TABLE, VACUUM, and
* unqualified LOCK TABLE
*/
extern LOCKMETHOD LockTableId;

4
src/include/storage/lock.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: lock.h,v 1.44 2001/01/25 03:31:16 tgl Exp $
* $Id: lock.h,v 1.45 2001/02/22 23:02:33 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@ -60,7 +60,7 @@ typedef int LOCKMODE;
typedef int LOCKMETHOD;
/* MAX_LOCKMODES cannot be larger than the # of bits in LOCKMASK */
#define MAX_LOCKMODES 8
#define MAX_LOCKMODES 8
/*
* MAX_LOCK_METHODS corresponds to the number of spin locks allocated in