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 
Reviewed-by: Kyotaro Horiguchi 
Reviewed-by: Álvaro Herrera 
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 3e71aea71f35f2c04322633ef9e7e1e610688132..b89c58118e903798af4ea13d5f7dfd574fc98788 100644 (file)
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -10592,6 +10592,10 @@ VerifyOverwriteContrecord(xl_overwrite_contrecord *xlrec, XLogReaderState *state
             LSN_FORMAT_ARGS(xlrec->overwritten_lsn),
             LSN_FORMAT_ARGS(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",
                    LSN_FORMAT_ARGS(xlrec->overwritten_lsn),

diff --git a/src/test/recovery/t/026_overwrite_contrecord.pl b/src/test/recovery/t/026_overwrite_contrecord.pl
index cb7f5b68c6500be4d61e478de6702cf21d82a62e..d451fe6b224d036c8ab3ee21818cc7a048deb71b 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;