From: Michael Paquier Date: Tue, 30 Sep 2025 00:38:32 +0000 (+0900) Subject: Reorder XLogNeedsFlush() checks to be more consistent X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bb68cde4136b02a7e51e8876891cd0a61c5726ca;p=thirdparty%2Fpostgresql.git Reorder XLogNeedsFlush() checks to be more consistent During recovery, XLogNeedsFlush() checks the minimum recovery LSN point instead of the flush LSN point. The same condition checks are used when updating the minimum recovery point in UpdateMinRecoveryPoint(), but are written in reverse order. This commit makes the order of the checks consistent between XLogNeedsFlush() and UpdateMinRecoveryPoint(), improving the code clarity. Note that the second check (as ordered by this commit) relies on InRecovery, which is true only in the startup process. So this makes XLogNeedsFlush() cheaper in the startup process with the first check acting as a shortcut while doing crash recovery, where LocalMinRecoveryPoint is an invalid LSN. Author: Melanie Plageman Reviewed-by: Dilip Kumar Discussion: https://postgr.es/m/aMIHNRTP6Wj6vw1s%40paquier.xyz --- diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 109713315c0..eceab341255 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -3134,6 +3134,10 @@ XLogNeedsFlush(XLogRecPtr record) */ if (!XLogInsertAllowed()) { + /* Quick exit if already known to be updated or cannot be updated */ + if (!updateMinRecoveryPoint || record <= LocalMinRecoveryPoint) + return false; + /* * An invalid minRecoveryPoint means that we need to recover all the * WAL, i.e., we're doing crash recovery. We never modify the control @@ -3143,11 +3147,10 @@ XLogNeedsFlush(XLogRecPtr record) * it has not replayed all WAL available when doing crash recovery. */ if (XLogRecPtrIsInvalid(LocalMinRecoveryPoint) && InRecovery) + { updateMinRecoveryPoint = false; - - /* Quick exit if already known to be updated or cannot be updated */ - if (record <= LocalMinRecoveryPoint || !updateMinRecoveryPoint) return false; + } /* * Update local copy of minRecoveryPoint. But if the lock is busy,