summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorMichael Paquier2023-02-22 01:14:52 +0000
committerMichael Paquier2023-02-22 01:14:52 +0000
commit8a8661828ae14e4d3b6beac5e8d8b37bd4e79004 (patch)
tree560fae46ba540a62f7e7175230375178d2d86d5f
parentb3e184a5d4fdbc43d2cb99865ea2e073c09b9584 (diff)
Fix corruption of templates after CREATE DATABASE .. STRATEGY WAL_LOG
WAL_LOG does a scan of the template's pg_class to determine the set of relations that need to be copied from a template database to the new one. However, as coded in 9c08aea, this copy strategy would load the pages of pg_class without considering it as a permanent relation, causing the loaded pages to never be flushed when they should. Any modification of the template's pg_class, mostly through DDLs, would then be missed, causing corruptions. STRATEGY = WAL_LOG is the default over FILE_COPY since it has been introduced, so any changes done to pg_class on a database template would be gone. Updates of database templates should be a rare thing, so the impact of this bug should be hopefully limited. The pre-14 default strategy FILE_COPY is safe, and can be used as a workaround. Ryo Matsumura has found and analyzed the issue, and Nathan has written a test able to reproduce the failure (with few tweaks from me). Backpatch down to 15, where STRATEGY = WAL_LOG has been introduced. Author: Nathan Bossart, Ryo Matsumura Reviewed-by: Dilip Kumar, Michael Paquier Discussion: https://postgr.es/m/TYCPR01MB6868677E499C9AD5123084B5E8A39@TYCPR01MB6868.jpnprd01.prod.outlook.com Backpatch-through: 15
-rw-r--r--src/backend/commands/dbcommands.c2
-rw-r--r--src/test/recovery/meson.build1
-rw-r--r--src/test/recovery/t/034_create_database.pl45
3 files changed, 47 insertions, 1 deletions
diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index ef05633bb0..a0259cc593 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -296,7 +296,7 @@ ScanSourceDatabasePgClass(Oid tbid, Oid dbid, char *srcpath)
CHECK_FOR_INTERRUPTS();
buf = ReadBufferWithoutRelcache(rlocator, MAIN_FORKNUM, blkno,
- RBM_NORMAL, bstrategy, false);
+ RBM_NORMAL, bstrategy, true);
LockBuffer(buf, BUFFER_LOCK_SHARE);
page = BufferGetPage(buf);
diff --git a/src/test/recovery/meson.build b/src/test/recovery/meson.build
index 209118a639..59465b97f3 100644
--- a/src/test/recovery/meson.build
+++ b/src/test/recovery/meson.build
@@ -39,6 +39,7 @@ tests += {
't/031_recovery_conflict.pl',
't/032_relfilenode_reuse.pl',
't/033_replay_tsp_drops.pl',
+ 't/034_create_database.pl',
],
},
}
diff --git a/src/test/recovery/t/034_create_database.pl b/src/test/recovery/t/034_create_database.pl
new file mode 100644
index 0000000000..4698cbc391
--- /dev/null
+++ b/src/test/recovery/t/034_create_database.pl
@@ -0,0 +1,45 @@
+
+# Copyright (c) 2023, PostgreSQL Global Development Group
+
+# Test WAL replay for CREATE DATABASE .. STRATEGY WAL_LOG.
+
+use strict;
+use warnings;
+use PostgreSQL::Test::Cluster;
+use PostgreSQL::Test::Utils;
+use Test::More;
+
+my $node = PostgreSQL::Test::Cluster->new('node');
+$node->init;
+$node->start;
+
+# This checks that any DDLs run on the template database that modify pg_class
+# are persisted after creating a database from it using the WAL_LOG strategy,
+# as a direct copy of the template database's pg_class is used in this case.
+my $db_template = "template1";
+my $db_new = "test_db_1";
+
+# Create table. It should persist on the template database.
+$node->safe_psql("postgres",
+ "CREATE DATABASE $db_new STRATEGY WAL_LOG TEMPLATE $db_template;");
+
+$node->safe_psql($db_template, "CREATE TABLE tab_db_after_create_1 (a INT);");
+
+# Flush the changes affecting the template database, then replay them.
+$node->safe_psql("postgres", "CHECKPOINT;");
+
+$node->stop('immediate');
+$node->start;
+my $result = $node->safe_psql($db_template,
+ "SELECT count(*) FROM pg_class WHERE relname LIKE 'tab_db_%';");
+is($result, "1",
+ "check that table exists on template after crash, with checkpoint");
+
+# The new database should have no tables.
+$result = $node->safe_psql($db_new,
+ "SELECT count(*) FROM pg_class WHERE relname LIKE 'tab_db_%';");
+is($result, "0",
+ "check that there are no tables from template on new database after crash"
+);
+
+done_testing();