This includes a couple of changes around the new behavior of pg_rewind
which enforces recovery to happen once on a cluster not shut down
cleanly:
- Some comments and documentation improvements.
- Shutdown the cluster to rewind with immediate mode in all the tests,
this allows to check after the forced recovery behavior which is wanted
as new default.
- Use -F for the forced recovery step, so as postgres does not use
fsync. This was useless as a final sync is done once the tool is done.
Author: Michael Paquier
Reviewed-by: Alexey Kondratov
Discussion: https://postgr.es/m/
20191004083721.GA1829@paquier.xyz
<term><option>--no-ensure-shutdown</option></term>
<listitem>
<para>
- <application>pg_rewind</application> verifies that the target server
- is cleanly shutdown before rewinding; by default, if it isn't, it
- starts the server in single-user mode to complete crash recovery.
+ <application>pg_rewind</application> requires that the target server
+ is cleanly shut down before rewinding. By default, if the target server
+ is not shut down cleanly, <application>pg_rewind</application> starts
+ the target server in single-user mode to complete crash recovery first,
+ and stops it.
By passing this option, <application>pg_rewind</application> skips
this and errors out immediately if the server is not cleanly shut
- down. Users are expected to handle the situation themselves in that
+ down. Users are expected to handle the situation themselves in that
case.
</para>
</listitem>
pg_free(buffer);
/*
- * If the target instance was not cleanly shut down, run a single-user
- * postgres session really quickly and reload the control file to get the
- * new state. Note if no_ensure_shutdown is specified, pg_rewind won't do
- * that automatically. That means users need to do themselves in advance,
- * else pg_rewind will soon quit, see sanityChecks().
+ * If the target instance was not cleanly shut down, start and stop the
+ * target cluster once in single-user mode to enforce recovery to finish,
+ * ensuring that the cluster can be used by pg_rewind. Note that if
+ * no_ensure_shutdown is specified, pg_rewind ignores this step, and users
+ * need to make sure by themselves that the target cluster is in a clean
+ * state.
*/
if (!no_ensure_shutdown &&
ControlFile_target.state != DB_SHUTDOWNED &&
if (dry_run)
return;
- /* finally run postgres in single-user mode */
- snprintf(cmd, MAXCMDLEN, "\"%s\" --single -D \"%s\" template1 < \"%s\"",
+ /*
+ * Finally run postgres in single-user mode. There is no need to use
+ * fsync here. This makes the recovery faster, and the target data folder
+ * is synced at the end anyway.
+ */
+ snprintf(cmd, MAXCMDLEN, "\"%s\" --single -F -D \"%s\" template1 < \"%s\"",
exec_path, datadir_target, DEVNULL);
if (system(cmd) != 0)
+#
+# Test that running pg_rewind with the source and target clusters
+# on the same timeline runs successfully.
+#
use strict;
use warnings;
use TestLib;
# Append the rewind-specific role to the connection string.
$standby_connstr = "$standby_connstr user=rewind_user";
- # Stop the master and be ready to perform the rewind
- $node_master->stop;
+ # Stop the master and be ready to perform the rewind. The cluster
+ # needs recovery to finish once, and pg_rewind makes sure that it
+ # happens automatically.
+ $node_master->stop('immediate');
# At this point, the rewind processing is ready to run.
# We now have a very simple scenario with a few diverged WAL record.
}
elsif ($test_mode eq "remote")
{
-
- # Do rewind using a remote connection as source
+ # Do rewind using a remote connection as source, generating
+ # recovery configuration automatically.
command_ok(
[
'pg_rewind', "--debug",
"--source-server", $standby_connstr,
- "--target-pgdata=$master_pgdata", "-R",
- "--no-sync"
+ "--target-pgdata=$master_pgdata", "--no-sync",
+ "--write-recovery-conf"
],
'pg_rewind remote');
- # Check that standby.signal has been created.
- ok(-e "$master_pgdata/standby.signal");
+ # Check that standby.signal is here as recovery configuration
+ # was requested.
+ ok( -e "$master_pgdata/standby.signal",
+ 'standby.signal created after pg_rewind');
# Now, when pg_rewind apparently succeeded with minimal permissions,
# add REPLICATION privilege. So we could test that new standby