diff options
Diffstat (limited to 'src/backend/storage/lmgr/lock.c')
| -rw-r--r-- | src/backend/storage/lmgr/lock.c | 43 |
1 files changed, 25 insertions, 18 deletions
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 98a2f366b4d..1c5ab8c0d97 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -2791,9 +2791,7 @@ FastPathGetRelationLockEntry(LOCALLOCK *locallock) * so use of this function has to be thought about carefully. * * Note we never include the current xact's vxid in the result array, - * since an xact never blocks itself. Also, prepared transactions are - * ignored, which is a bit more debatable but is appropriate for current - * uses of the result. + * since an xact never blocks itself. */ VirtualTransactionId * GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) @@ -2818,19 +2816,21 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) /* * Allocate memory to store results, and fill with InvalidVXID. We only - * need enough space for MaxBackends + a terminator, since prepared xacts - * don't count. InHotStandby allocate once in TopMemoryContext. + * need enough space for MaxBackends + max_prepared_xacts + a terminator. + * InHotStandby allocate once in TopMemoryContext. */ if (InHotStandby) { if (vxids == NULL) vxids = (VirtualTransactionId *) MemoryContextAlloc(TopMemoryContext, - sizeof(VirtualTransactionId) * (MaxBackends + 1)); + sizeof(VirtualTransactionId) * + (MaxBackends + max_prepared_xacts + 1)); } else vxids = (VirtualTransactionId *) - palloc0(sizeof(VirtualTransactionId) * (MaxBackends + 1)); + palloc0(sizeof(VirtualTransactionId) * + (MaxBackends + max_prepared_xacts + 1)); /* Compute hash code and partition lock, and look up conflicting modes. */ hashcode = LockTagHashCode(locktag); @@ -2905,13 +2905,9 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) /* Conflict! */ GET_VXID_FROM_PGPROC(vxid, *proc); - /* - * If we see an invalid VXID, then either the xact has already - * committed (or aborted), or it's a prepared xact. In either - * case we may ignore it. - */ if (VirtualTransactionIdIsValid(vxid)) vxids[count++] = vxid; + /* else, xact already committed or aborted */ /* No need to examine remaining slots. */ break; @@ -2968,11 +2964,6 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) GET_VXID_FROM_PGPROC(vxid, *proc); - /* - * If we see an invalid VXID, then either the xact has already - * committed (or aborted), or it's a prepared xact. In either - * case we may ignore it. - */ if (VirtualTransactionIdIsValid(vxid)) { int i; @@ -2984,6 +2975,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) if (i >= fast_count) vxids[count++] = vxid; } + /* else, xact already committed or aborted */ } } @@ -2993,7 +2985,7 @@ GetLockConflicts(const LOCKTAG *locktag, LOCKMODE lockmode) LWLockRelease(partitionLock); - if (count > MaxBackends) /* should never happen */ + if (count > MaxBackends + max_prepared_xacts) /* should never happen */ elog(PANIC, "too many conflicting locks found"); vxids[count].backendId = InvalidBackendId; @@ -4349,6 +4341,21 @@ VirtualXactLock(VirtualTransactionId vxid, bool wait) Assert(VirtualTransactionIdIsValid(vxid)); + if (VirtualTransactionIdIsPreparedXact(vxid)) + { + LockAcquireResult lar; + + /* + * Prepared transactions don't hold vxid locks. The + * LocalTransactionId is always a normal, locked XID. + */ + SET_LOCKTAG_TRANSACTION(tag, vxid.localTransactionId); + lar = LockAcquire(&tag, ShareLock, false, !wait); + if (lar != LOCKACQUIRE_NOT_AVAIL) + LockRelease(&tag, ShareLock, false); + return lar != LOCKACQUIRE_NOT_AVAIL; + } + SET_LOCKTAG_VIRTUALTRANSACTION(tag, vxid); /* |