diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/storage/lmgr/lock.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/src/backend/storage/lmgr/lock.c b/src/backend/storage/lmgr/lock.c index 9f55132724f..be44913e2a0 100644 --- a/src/backend/storage/lmgr/lock.c +++ b/src/backend/storage/lmgr/lock.c @@ -185,6 +185,18 @@ static int FastPathLocalUseCount = 0; */ static bool IsRelationExtensionLockHeld PG_USED_FOR_ASSERTS_ONLY = false; +/* + * Flag to indicate if the page lock is held by this backend. We don't + * acquire any other heavyweight lock while holding the page lock except for + * relation extension. However, these locks are never taken in reverse order + * which implies that page locks will also never participate in the deadlock + * cycle. + * + * Similar to relation extension, page locks are also held for a short + * duration, so imposing such a restriction won't hurt. + */ +static bool IsPageLockHeld PG_USED_FOR_ASSERTS_ONLY = false; + /* Macros for manipulating proc->fpLockBits */ #define FAST_PATH_BITS_PER_SLOT 3 #define FAST_PATH_LOCKNUMBER_OFFSET 1 @@ -863,6 +875,13 @@ LockAcquireExtended(const LOCKTAG *locktag, Assert(!IsRelationExtensionLockHeld); /* + * We don't acquire any other heavyweight lock while holding the page lock + * except for relation extension. + */ + Assert(!IsPageLockHeld || + (locktag->locktag_type == LOCKTAG_RELATION_EXTEND)); + + /* * Prepare to emit a WAL record if acquisition of this lock needs to be * replayed in a standby server. * @@ -1310,10 +1329,10 @@ SetupLockInTable(LockMethod lockMethodTable, PGPROC *proc, } /* - * Check and set/reset the flag that we hold the relation extension lock. + * Check and set/reset the flag that we hold the relation extension/page lock. * * It is callers responsibility that this function is called after - * acquiring/releasing the relation extension lock. + * acquiring/releasing the relation extension/page lock. * * Pass acquired as true if lock is acquired, false otherwise. */ @@ -1323,6 +1342,9 @@ CheckAndSetLockHeld(LOCALLOCK *locallock, bool acquired) #ifdef USE_ASSERT_CHECKING if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_RELATION_EXTEND) IsRelationExtensionLockHeld = acquired; + else if (LOCALLOCK_LOCKTAG(*locallock) == LOCKTAG_PAGE) + IsPageLockHeld = acquired; + #endif } |