From 04bda25a7d52526282f3f1a0437077c94794b5a2 Mon Sep 17 00:00:00 2001 From: Michael Paquier Date: Mon, 15 Dec 2025 17:48:07 +0900 Subject: [PATCH v4] Check presence of REDO record --- src/backend/access/transam/xlog.c | 6 + src/backend/access/transam/xlogrecovery.c | 10 ++ src/test/recovery/meson.build | 1 + .../recovery/t/050_redo_segment_missing.pl | 117 ++++++++++++++++++ 4 files changed, 134 insertions(+) create mode 100644 src/test/recovery/t/050_redo_segment_missing.pl diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 6a5640df51af..430a38b1a216 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7001,6 +7001,10 @@ CreateCheckPoint(int flags) */ SyncPreCheckpoint(); + /* Run these points outside the critical section. */ + INJECTION_POINT("create-checkpoint-initial", NULL); + INJECTION_POINT_LOAD("create-checkpoint-run"); + /* * Use a critical section to force system panic if we have trouble. */ @@ -7151,6 +7155,8 @@ CreateCheckPoint(int flags) if (log_checkpoints) LogCheckpointStart(flags, false); + INJECTION_POINT_CACHED("create-checkpoint-run", NULL); + /* Update the process title */ update_checkpoint_display(flags, false, false); diff --git a/src/backend/access/transam/xlogrecovery.c b/src/backend/access/transam/xlogrecovery.c index ae2398d6975b..38b594d21709 100644 --- a/src/backend/access/transam/xlogrecovery.c +++ b/src/backend/access/transam/xlogrecovery.c @@ -805,6 +805,16 @@ InitWalRecovery(ControlFileData *ControlFile, bool *wasShutdown_ptr, } memcpy(&checkPoint, XLogRecGetData(xlogreader), sizeof(CheckPoint)); wasShutdown = ((record->xl_info & ~XLR_INFO_MASK) == XLOG_CHECKPOINT_SHUTDOWN); + + /* Make sure that REDO location exists. */ + if (checkPoint.redo < CheckPointLoc) + { + XLogPrefetcherBeginRead(xlogprefetcher, checkPoint.redo); + if (!ReadRecord(xlogprefetcher, LOG, false, checkPoint.ThisTimeLineID)) + ereport(FATAL, + errmsg("could not find redo location %X/%08X referenced by checkpoint record at %X/%08X", + LSN_FORMAT_ARGS(checkPoint.redo), LSN_FORMAT_ARGS(CheckPointLoc))); + } } if (ArchiveRecoveryRequested) diff --git a/src/test/recovery/meson.build b/src/test/recovery/meson.build index 523a5cd5b527..e93248bd66e2 100644 --- a/src/test/recovery/meson.build +++ b/src/test/recovery/meson.build @@ -58,6 +58,7 @@ tests += { 't/047_checkpoint_physical_slot.pl', 't/048_vacuum_horizon_floor.pl', 't/049_wait_for_lsn.pl', + 't/050_redo_segment_missing.pl', ], }, } diff --git a/src/test/recovery/t/050_redo_segment_missing.pl b/src/test/recovery/t/050_redo_segment_missing.pl new file mode 100644 index 000000000000..113477e01520 --- /dev/null +++ b/src/test/recovery/t/050_redo_segment_missing.pl @@ -0,0 +1,117 @@ +# Copyright (c) 2025, PostgreSQL Global Development Group +# +# Evaluates PostgreSQL's recovery behavior when a WAL segment containing the +# redo record is missing, with a checkpoint record located in a different +# segment. + +use strict; +use warnings FATAL => 'all'; +use PostgreSQL::Test::Cluster; +use PostgreSQL::Test::Utils; +use Test::More; + +if ($ENV{enable_injection_points} ne 'yes') +{ + plan skip_all => 'Injection points not supported by this build'; +} + +my $node = PostgreSQL::Test::Cluster->new('testnode'); +$node->init; +$node->append_conf('postgresql.conf', 'log_checkpoints = on'); +$node->start; + +# Check if the extension injection_points is available, as it may be +# possible that this script is run with installcheck, where the module +# would not be installed by default. +if (!$node->check_extension('injection_points')) +{ + plan skip_all => 'Extension injection_points not installed'; +} +$node->safe_psql('postgres', q(CREATE EXTENSION injection_points)); + +# Note that this uses two injection points based on waits, not one. +# This may look strange, but this works as a workaround to enforce +# all memory allocations to happen outside the critical section of a +# checkpoint. +# First, "create-checkpoint-initial" is run outside the critical +# section, and is used as a way to initialize the shared memory required +# for the wait machinery with its DSM registry. +# Then, "create-checkpoint-run" is run inside the critical section of +# a checkpoint, with its callback loaded outside its critical section to +# allocate any memory required by the callback. +$node->safe_psql('postgres', + q{select injection_points_attach('create-checkpoint-initial', 'wait')}); +$node->safe_psql('postgres', + q{select injection_points_attach('create-checkpoint-run', 'wait')}); + +# Start a psql session to run the checkpoint in the background and make +# the test wait on the injection point so the checkpoint stops just after +# it starts. +my $checkpoint = $node->background_psql('postgres'); +$checkpoint->query_until( + qr/starting_checkpoint/, + q(\echo starting_checkpoint +checkpoint; +)); + +# Wait for initialization point to finish, the checkpointer is still +# outside its critical section. Then release to reach the second +# point. +$node->wait_for_event('checkpointer', 'create-checkpoint-initial'); +$node->safe_psql('postgres', + q{select injection_points_wakeup('create-checkpoint-initial')}); + +# Wait until the checkpoint has reached the second injection point, +# we are now in the middle of a checkpoint running after the redo +# record has been logged. +$node->wait_for_event('checkpointer', 'create-checkpoint-run'); + +# Switch the WAL segment, ensuring that the redo record will be +# included in a different segment than the checkpoint record. +$node->safe_psql('postgres', 'SELECT pg_switch_wal()'); + +# Continue the checkpoint and wait for its completion. +my $log_offset = -s $node->logfile; +$node->safe_psql('postgres', + q{select injection_points_wakeup('create-checkpoint-run')}); +$node->wait_for_log(qr/checkpoint complete/, $log_offset); + +$checkpoint->quit; + +# Retrieve the WAL file names for the redo record and checkpoint record. +my $redo_lsn = $node->safe_psql('postgres', + "SELECT redo_lsn FROM pg_control_checkpoint()"); +my $redo_walfile_name = + $node->safe_psql('postgres', "SELECT pg_walfile_name('$redo_lsn')"); +my $checkpoint_lsn = $node->safe_psql('postgres', + "SELECT checkpoint_lsn FROM pg_control_checkpoint()"); +my $checkpoint_walfile_name = + $node->safe_psql('postgres', "SELECT pg_walfile_name('$checkpoint_lsn')"); + +# Redo record and checkpoint record should be on different segments. +isnt($redo_walfile_name, $checkpoint_walfile_name, + 'redo and checkpoint records on different segments'); + +# Remove the WAL segment containing the redo record. +unlink $node->data_dir . "/pg_wal/$redo_walfile_name" + or die "Could not remove WAL file: $!"; + +$node->stop('immediate'); + +# Use run_log instead of node->start because this test expects +# that the server ends with an error during recovery. +run_log( + [ + 'pg_ctl', + '--pgdata' => $node->data_dir, + '--log' => $node->logfile, + 'start', + ]); + +# Confirm that recovery has failed, as expected. +my $logfile = slurp_file($node->logfile()); +ok( $logfile =~ + qr/FATAL: could not find redo location .* referenced by checkpoint record at .*/, + "ends with FATAL because it could not find redo location"); + +done_testing(); -- 2.51.0