From fa9f2e31756225f4e17103d22d9e651bf8d41941 Mon Sep 17 00:00:00 2001 From: Fujii Masao Date: Tue, 17 Mar 2026 08:10:20 +0900 Subject: [PATCH] Fix WAL flush LSN used by logical walsender during shutdown Commit 6eedb2a5fd8 made the logical walsender call XLogFlush(GetXLogInsertRecPtr()) to ensure that all pending WAL is flushed, fixing a publisher shutdown hang. However, if the last WAL record ends at a page boundary, GetXLogInsertRecPtr() can return an LSN pointing past the page header, which can cause XLogFlush() to report an error. A similar issue previously existed in the GiST code. Commit b1f14c96720 introduced GetXLogInsertEndRecPtr(), which returns a safe WAL insertion end location (returning the start of the page when the last record ends at a page boundary), and updated the GiST code to use it with XLogFlush(). This commit fixes the issue by making the logical walsender use XLogFlush(GetXLogInsertEndRecPtr()) when flushing pending WAL during shutdown. Backpatch to all supported versions. Reported-by: Andres Freund Author: Anthonin Bonnefoy Reviewed-by: Fujii Masao Discussion: https://postgr.es/m/vzguaguldbcyfbyuq76qj7hx5qdr5kmh67gqkncyb2yhsygrdt@dfhcpteqifux Backpatch-through: 14 --- src/backend/replication/walsender.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 566f8a232e4..eadc800c9ca 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1602,9 +1602,15 @@ WalSndWaitForWal(XLogRecPtr loc) * If we're shutting down, trigger pending WAL to be written out, * otherwise we'd possibly end up waiting for WAL that never gets * written, because walwriter has shut down already. + * + * Note that GetXLogInsertEndRecPtr() is used to obtain the WAL flush + * request location instead of GetXLogInsertRecPtr(). Because if the + * last WAL record ends at a page boundary, GetXLogInsertRecPtr() can + * return an LSN pointing past the page header, which may cause + * XLogFlush() to report an error. */ if (got_STOPPING && !RecoveryInProgress()) - XLogFlush(GetXLogInsertRecPtr()); + XLogFlush(GetXLogInsertEndRecPtr()); /* Update our idea of the currently flushed position. */ if (!RecoveryInProgress())