Fix "missing continuation record" after standby promotion

Invalidate abortedRecPtr and missingContrecPtr after a missing
continuation record is successfully skipped on a standby. This fixes a
PANIC caused when a recently promoted standby attempts to write an
OVERWRITE_RECORD with an LSN of the previously read aborted record.

Backpatch to 10 (all stable versions).

Author: Sami Imseih <simseih@amazon.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/44D259DE-7542-49C4-8A52-2AB01534DCA9@amazon.com

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index a30314bc8309f65fa92d606f8ed6bf4d8b9e2bfd..330aa9ddd04d0fbcf90c776ea56fa2674e162ee0 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -10149,6 +10149,10 @@ VerifyOverwriteContrecord(xl_overwrite_contrecord *xlrec, XLogReaderState *state
                         (uint32) (state->overwrittenRecPtr >> 32),
                         (uint32) state->overwrittenRecPtr);
 
+       /* We have safely skipped the aborted record */
+       abortedRecPtr = InvalidXLogRecPtr;
+       missingContrecPtr = InvalidXLogRecPtr;
+
        ereport(LOG,
                        (errmsg("successfully skipped missing contrecord at %X/%X, overwritten at %s",
                                        (uint32) (xlrec->overwritten_lsn >> 32),

diff --git a/src/test/recovery/t/026_overwrite_contrecord.pl b/src/test/recovery/t/026_overwrite_contrecord.pl
index 867b75937eb65ecd2471fdbe749501d9ce73d015..693f7dff877e3505981ea1b2f18b5f1d848986f4 100644 (file)
--- a/src/test/recovery/t/026_overwrite_contrecord.pl
+++ b/src/test/recovery/t/026_overwrite_contrecord.pl
@@ -15,7 +15,7 @@ plan tests => 3;
 # Test: Create a physical replica that's missing the last WAL file,
 # then restart the primary to create a divergent WAL file and observe
 # that the replica replays the "overwrite contrecord" from that new
-# file.
+# file and the standby promotes successfully.
 
 my $node = PostgresNode->get_new_node('primary');
 $node->init(allows_streaming => 1);
@@ -102,5 +102,8 @@ like(
        qr[successfully skipped missing contrecord at],
        "found log line in standby");
 
+# Verify promotion is successful
+$node_standby->promote;
+
 $node->stop;
 $node_standby->stop;