Revert recent changes related to handling of 2PC files at recovery

michaelpq · michaelpq · commit 060f9f5ea537 · 2025-01-17T13:27:47.000+09:00
This commit reverts 8f67f99 (down to v13) and c3de0f9 (down to v17), as these are proving to not be completely correct regarding two aspects: - In v17 and newer branches, c3de0f9's check for epoch handling is incorrect, and does not correctly handle frozen epochs. A logic closer to widen_snapshot_xid() should be used. The 2PC code should try to integrate deeper with FullTransactionIds, 5a1dfde being not enough. - In v13 and newer branches, 8f67f99 is a workaround for the real issue, which is that we should not attempt CLOG lookups without reaching consistency. This exists since 728bd99, and this is reachable with ProcessTwoPhaseBuffer() called by restoreTwoPhaseData() at the beginning of recovery. Per discussion with Noah Misch. Discussion: https://postgr.es/m/20250116010051.f3.nmisch@google.com Backpatch-through: 13
diff --git a/src/backend/access/transam/twophase.c b/src/backend/access/transam/twophase.c
@@ -2156,40 +2156,40 @@ ProcessTwoPhaseBuffer(TransactionId xid,
 	if (!fromdisk)
 		Assert(prepare_start_lsn != InvalidXLogRecPtr);
 
-	/* Reject XID if too new */
-	if (TransactionIdFollowsOrEquals(xid, origNextXid))
+	/* Already processed? */
+	if (TransactionIdDidCommit(xid) || TransactionIdDidAbort(xid))
 	{
 		if (fromdisk)
 		{
 			ereport(WARNING,
-					(errmsg("removing future two-phase state file for transaction %u",
+					(errmsg("removing stale two-phase state file for transaction %u",
 							xid)));
 			RemoveTwoPhaseFile(xid, true);
 		}
 		else
 		{
 			ereport(WARNING,
-					(errmsg("removing future two-phase state from memory for transaction %u",
+					(errmsg("removing stale two-phase state from memory for transaction %u",
 							xid)));
 			PrepareRedoRemove(xid, true);
 		}
 		return NULL;
 	}
 
-	/* Already processed? */
-	if (TransactionIdDidCommit(xid) || TransactionIdDidAbort(xid))
+	/* Reject XID if too new */
+	if (TransactionIdFollowsOrEquals(xid, origNextXid))
 	{
 		if (fromdisk)
 		{
 			ereport(WARNING,
-					(errmsg("removing stale two-phase state file for transaction %u",
+					(errmsg("removing future two-phase state file for transaction %u",
 							xid)));
 			RemoveTwoPhaseFile(xid, true);
 		}
 		else
 		{
 			ereport(WARNING,
-					(errmsg("removing stale two-phase state from memory for transaction %u",
+					(errmsg("removing future two-phase state from memory for transaction %u",
 							xid)));
 			PrepareRedoRemove(xid, true);
 		}
diff --git a/src/test/recovery/t/009_twophase.pl b/src/test/recovery/t/009_twophase.pl
@@ -7,7 +7,7 @@
 
 use PostgresNode;
 use TestLib;
-use Test::More tests => 28;
+use Test::More tests => 27;
 
 my $psql_out = '';
 my $psql_rc  = '';
@@ -527,26 +527,3 @@ sub configure_and_reload
 is( $psql_out,
 	qq{27|issued to paris},
 	"Check expected t_009_tbl2 data on standby");
-
-###############################################################################
-# Check handling of orphaned 2PC files at recovery.
-###############################################################################
-
-$cur_primary->teardown_node;
-
-# Grab location in logs of primary
-my $log_offset = -s $cur_primary->logfile;
-
-# Create a fake file with a transaction ID large enough to be in the future,
-# then check that the primary is able to start and remove this file at
-# recovery.
-
-my $future_2pc_file = $cur_primary->data_dir . '/pg_twophase/00FFFFFF';
-append_to_file $future_2pc_file, "";
-
-$cur_primary->start;
-$cur_primary->log_check(
-	"future two-phase file removed at recovery",
-	$log_offset,
-	log_like =>
-	  [qr/removing future two-phase state file for transaction 16777215/]);

Original file line number	Diff line number	Diff line change
`@@ -2156,40 +2156,40 @@ ProcessTwoPhaseBuffer(TransactionId xid,`
`2156`	`2156`	`if (!fromdisk)`
`2157`	`2157`	`Assert(prepare_start_lsn != InvalidXLogRecPtr);`
`2158`	`2158`
`2159`		`- /* Reject XID if too new */`
`2160`		`- if (TransactionIdFollowsOrEquals(xid, origNextXid))`
	`2159`	`+ /* Already processed? */`
	`2160`	`+ if (TransactionIdDidCommit(xid) \|\| TransactionIdDidAbort(xid))`
`2161`	`2161`	`{`
`2162`	`2162`	`if (fromdisk)`
`2163`	`2163`	`{`
`2164`	`2164`	`ereport(WARNING,`
`2165`		`- (errmsg("removing future two-phase state file for transaction %u",`
	`2165`	`+ (errmsg("removing stale two-phase state file for transaction %u",`
`2166`	`2166`	`xid)));`
`2167`	`2167`	`RemoveTwoPhaseFile(xid, true);`
`2168`	`2168`	`}`
`2169`	`2169`	`else`
`2170`	`2170`	`{`
`2171`	`2171`	`ereport(WARNING,`
`2172`		`- (errmsg("removing future two-phase state from memory for transaction %u",`
	`2172`	`+ (errmsg("removing stale two-phase state from memory for transaction %u",`
`2173`	`2173`	`xid)));`
`2174`	`2174`	`PrepareRedoRemove(xid, true);`
`2175`	`2175`	`}`
`2176`	`2176`	`return NULL;`
`2177`	`2177`	`}`
`2178`	`2178`
`2179`		`- /* Already processed? */`
`2180`		`- if (TransactionIdDidCommit(xid) \|\| TransactionIdDidAbort(xid))`
	`2179`	`+ /* Reject XID if too new */`
	`2180`	`+ if (TransactionIdFollowsOrEquals(xid, origNextXid))`
`2181`	`2181`	`{`
`2182`	`2182`	`if (fromdisk)`
`2183`	`2183`	`{`
`2184`	`2184`	`ereport(WARNING,`
`2185`		`- (errmsg("removing stale two-phase state file for transaction %u",`
	`2185`	`+ (errmsg("removing future two-phase state file for transaction %u",`
`2186`	`2186`	`xid)));`
`2187`	`2187`	`RemoveTwoPhaseFile(xid, true);`
`2188`	`2188`	`}`
`2189`	`2189`	`else`
`2190`	`2190`	`{`
`2191`	`2191`	`ereport(WARNING,`
`2192`		`- (errmsg("removing stale two-phase state from memory for transaction %u",`
	`2192`	`+ (errmsg("removing future two-phase state from memory for transaction %u",`
`2193`	`2193`	`xid)));`
`2194`	`2194`	`PrepareRedoRemove(xid, true);`
`2195`	`2195`	`}`