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help / color / mirror / Atom feedFrom: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Subject: [PATCH v1 3/4] Apply the same timeline fix to read_local_xlog_page_guts()
Date: Mon, 8 Jun 2026 07:04:43 +0000
read_local_xlog_page_guts() has the same race as logical_read_xlog_page() (that
has been fixed in commit xxxxx): when RecoveryInProgress() returns true during
promotion, it gets the old timeline from GetXLogReplayRecPtr() while old WAL
segments may already be removed.
This affects SQL-callable logical decoding functions (pg_logical_slot_get_changes,
pg_logical_slot_peek_changes) running on a standby during promotion.
Apply the same fix: use GetWALInsertionTimeLineIfSet() to detect that the
insertion timeline is already established and use it directly.
Reported-by: Xuneng Zhou <xunengzhou@gmail.com>
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by:
Discussion: https://postgr.es/m/7daef094-abf3-4672-bc23-3df4763b16a3%40gmail.com
---
src/backend/access/transam/xlogutils.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
100.0% src/backend/access/transam/
diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 5fbe39133b8..fdc341d8fa4 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -896,7 +896,19 @@ read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPagePtr,
if (!RecoveryInProgress())
read_upto = GetFlushRecPtr(&currTLI);
else
+ {
+ TimeLineID insertTLI;
+
read_upto = GetXLogReplayRecPtr(&currTLI);
+
+ /*
+ * If the insertion timeline has already been set, use it. See
+ * logical_read_xlog_page() for details.
+ */
+ insertTLI = GetWALInsertionTimeLineIfSet();
+ if (insertTLI != 0)
+ currTLI = insertTLI;
+ }
tli = currTLI;
/*
--
2.34.1
--HitlKQoyB8givWgr
Content-Type: text/x-diff; charset=us-ascii
Content-Disposition: attachment;
filename="v1-0004-Add-SQL-path-test-for-read_local_xlog_page_guts-t.patch"
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To: pgsql-hackers@postgresql.org
Cc: bertranddrouvot.pg@gmail.com
Subject: Re: [PATCH v1 3/4] Apply the same timeline fix to read_local_xlog_page_guts()
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