From d9db17fb8ebaf1c57a51e2b5e47475fc855be04c Mon Sep 17 00:00:00 2001 From: John Morris Date: Wed, 3 May 2023 18:28:39 -0700 Subject: [PATCH] Use atomic ops for unloggedLSNs --- src/backend/access/transam/xlog.c | 23 ++++++----------------- 1 file changed, 6 insertions(+), 17 deletions(-) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index b2430f617c..9ed6cf4154 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -469,9 +469,8 @@ typedef struct XLogCtlData XLogSegNo lastRemovedSegNo; /* latest removed/recycled XLOG segment */ - /* Fake LSN counter, for unlogged relations. Protected by ulsn_lck. */ - XLogRecPtr unloggedLSN; - slock_t ulsn_lck; + /* Fake LSN counter for unlogged relations. Updated atomically. */ + pg_atomic_uint64 unloggedLSN; /* Time and LSN of last xlog segment switch. Protected by WALWriteLock. */ pg_time_t lastSegSwitchTime; @@ -4215,14 +4214,7 @@ DataChecksumsEnabled(void) XLogRecPtr GetFakeLSNForUnloggedRel(void) { - XLogRecPtr nextUnloggedLSN; - - /* increment the unloggedLSN counter, need SpinLock */ - SpinLockAcquire(&XLogCtl->ulsn_lck); - nextUnloggedLSN = XLogCtl->unloggedLSN++; - SpinLockRelease(&XLogCtl->ulsn_lck); - - return nextUnloggedLSN; + return pg_atomic_fetch_add_u64(&XLogCtl->unloggedLSN, 1); } /* @@ -4635,7 +4627,6 @@ XLOGShmemInit(void) SpinLockInit(&XLogCtl->Insert.insertpos_lck); SpinLockInit(&XLogCtl->info_lck); - SpinLockInit(&XLogCtl->ulsn_lck); } /* @@ -5240,9 +5231,9 @@ StartupXLOG(void) * the unlogged LSN counter can be reset too. */ if (ControlFile->state == DB_SHUTDOWNED) - XLogCtl->unloggedLSN = ControlFile->unloggedLSN; + pg_atomic_init_u64(&XLogCtl->unloggedLSN, ControlFile->unloggedLSN); else - XLogCtl->unloggedLSN = FirstNormalUnloggedLSN; + pg_atomic_init_u64(&XLogCtl->unloggedLSN, FirstNormalUnloggedLSN); /* * Copy any missing timeline history files between 'now' and the recovery @@ -6784,9 +6775,7 @@ CreateCheckPoint(int flags) * unused on non-shutdown checkpoints, but seems useful to store it always * for debugging purposes. */ - SpinLockAcquire(&XLogCtl->ulsn_lck); - ControlFile->unloggedLSN = XLogCtl->unloggedLSN; - SpinLockRelease(&XLogCtl->ulsn_lck); + ControlFile->unloggedLSN = pg_atomic_read_u64(&XLogCtl->unloggedLSN); UpdateControlFile(); LWLockRelease(ControlFileLock); -- 2.33.0