89ac7004da
Some code in the RewindTest test suite is more generally useful than just for that suite, so put it where other test suites can reach it. Some postgresql.conf parameters change their default values when a cluster is initialized with 'allows_streaming' than the previous behavior; most notably, autovacuum is no longer turned off. (Also, we no longer call pg_ctl promote with -w, but that flag doesn't actually do anything in promote so there's no behavior change.) Author: Michael Paquier
260 lines
7.1 KiB
Perl
260 lines
7.1 KiB
Perl
package RewindTest;
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# Test driver for pg_rewind. Each test consists of a cycle where a new cluster
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# is first created with initdb, and a streaming replication standby is set up
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# to follow the master. Then the master is shut down and the standby is
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# promoted, and finally pg_rewind is used to rewind the old master, using the
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# standby as the source.
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#
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# To run a test, the test script (in t/ subdirectory) calls the functions
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# in this module. These functions should be called in this sequence:
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#
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# 1. setup_cluster - creates a PostgreSQL cluster that runs as the master
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#
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# 2. start_master - starts the master server
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#
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# 3. create_standby - runs pg_basebackup to initialize a standby server, and
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# sets it up to follow the master.
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#
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# 4. promote_standby - runs "pg_ctl promote" to promote the standby server.
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# The old master keeps running.
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#
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# 5. run_pg_rewind - stops the old master (if it's still running) and runs
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# pg_rewind to synchronize it with the now-promoted standby server.
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#
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# 6. clean_rewind_test - stops both servers used in the test, if they're
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# still running.
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#
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# The test script can use the helper functions master_psql and standby_psql
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# to run psql against the master and standby servers, respectively. The
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# test script can also use the $connstr_master and $connstr_standby global
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# variables, which contain libpq connection strings for connecting to the
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# master and standby servers. The data directories are also available
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# in paths $test_master_datadir and $test_standby_datadir
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use strict;
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use warnings;
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use Config;
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use Exporter 'import';
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use File::Copy;
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use File::Path qw(rmtree);
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use IPC::Run qw(run);
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use PostgresNode;
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use TestLib;
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use Test::More;
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our @EXPORT = qw(
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$node_master
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$node_standby
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master_psql
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standby_psql
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check_query
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setup_cluster
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start_master
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create_standby
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promote_standby
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run_pg_rewind
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clean_rewind_test
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);
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# Our nodes.
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our $node_master;
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our $node_standby;
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sub master_psql
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{
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my $cmd = shift;
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system_or_bail 'psql', '-q', '--no-psqlrc', '-d',
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$node_master->connstr('postgres'), '-c', "$cmd";
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}
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sub standby_psql
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{
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my $cmd = shift;
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system_or_bail 'psql', '-q', '--no-psqlrc', '-d',
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$node_standby->connstr('postgres'), '-c', "$cmd";
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}
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# Run a query against the master, and check that the output matches what's
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# expected
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sub check_query
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{
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my ($query, $expected_stdout, $test_name) = @_;
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my ($stdout, $stderr);
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# we want just the output, no formatting
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my $result = run [
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'psql', '-q', '-A', '-t', '--no-psqlrc', '-d',
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$node_master->connstr('postgres'),
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'-c', $query ],
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'>', \$stdout, '2>', \$stderr;
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# We don't use ok() for the exit code and stderr, because we want this
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# check to be just a single test.
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if (!$result)
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{
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fail("$test_name: psql exit code");
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}
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elsif ($stderr ne '')
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{
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diag $stderr;
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fail("$test_name: psql no stderr");
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}
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else
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{
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$stdout =~ s/\r//g if $Config{osname} eq 'msys';
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is($stdout, $expected_stdout, "$test_name: query result matches");
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}
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}
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sub setup_cluster
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{
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# Initialize master, data checksums are mandatory
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$node_master = get_new_node('master');
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$node_master->init(allows_streaming => 1);
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}
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sub start_master
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{
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$node_master->start;
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#### Now run the test-specific parts to initialize the master before setting
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# up standby
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}
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sub create_standby
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{
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$node_standby = get_new_node('standby');
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$node_master->backup('my_backup');
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$node_standby->init_from_backup($node_master, 'my_backup');
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my $connstr_master = $node_master->connstr('postgres');
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$node_standby->append_conf(
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"recovery.conf", qq(
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primary_conninfo='$connstr_master application_name=rewind_standby'
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standby_mode=on
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recovery_target_timeline='latest'
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));
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# Start standby
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$node_standby->start;
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# The standby may have WAL to apply before it matches the primary. That
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# is fine, because no test examines the standby before promotion.
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}
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sub promote_standby
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{
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#### Now run the test-specific parts to run after standby has been started
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# up standby
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# Wait for the standby to receive and write all WAL.
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my $wal_received_query =
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"SELECT pg_current_xlog_location() = write_location FROM pg_stat_replication WHERE application_name = 'rewind_standby';";
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$node_master->poll_query_until('postgres', $wal_received_query)
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or die "Timed out while waiting for standby to receive and write WAL";
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# Now promote slave and insert some new data on master, this will put
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# the master out-of-sync with the standby. Wait until the standby is
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# out of recovery mode, and is ready to accept read-write connections.
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$node_standby->promote;
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$node_standby->poll_query_until('postgres',
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"SELECT NOT pg_is_in_recovery()")
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or die "Timed out while waiting for promotion of standby";
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# Force a checkpoint after the promotion. pg_rewind looks at the control
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# file to determine what timeline the server is on, and that isn't updated
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# immediately at promotion, but only at the next checkpoint. When running
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# pg_rewind in remote mode, it's possible that we complete the test steps
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# after promotion so quickly that when pg_rewind runs, the standby has not
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# performed a checkpoint after promotion yet.
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standby_psql("checkpoint");
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}
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sub run_pg_rewind
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{
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my $test_mode = shift;
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my $master_pgdata = $node_master->data_dir;
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my $standby_pgdata = $node_standby->data_dir;
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my $standby_connstr = $node_standby->connstr('postgres');
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my $tmp_folder = TestLib::tempdir;
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# Stop the master and be ready to perform the rewind
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$node_master->stop;
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# At this point, the rewind processing is ready to run.
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# We now have a very simple scenario with a few diverged WAL record.
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# The real testing begins really now with a bifurcation of the possible
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# scenarios that pg_rewind supports.
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# Keep a temporary postgresql.conf for master node or it would be
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# overwritten during the rewind.
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copy(
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"$master_pgdata/postgresql.conf",
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"$tmp_folder/master-postgresql.conf.tmp");
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# Now run pg_rewind
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if ($test_mode eq "local")
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{
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# Do rewind using a local pgdata as source
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# Stop the master and be ready to perform the rewind
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$node_standby->stop;
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command_ok(
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[ 'pg_rewind',
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"--debug",
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"--source-pgdata=$standby_pgdata",
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"--target-pgdata=$master_pgdata" ],
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'pg_rewind local');
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}
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elsif ($test_mode eq "remote")
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{
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# Do rewind using a remote connection as source
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command_ok(
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[ 'pg_rewind', "--debug",
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"--source-server", $standby_connstr,
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"--target-pgdata=$master_pgdata" ],
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'pg_rewind remote');
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}
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else
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{
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# Cannot come here normally
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die("Incorrect test mode specified");
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}
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# Now move back postgresql.conf with old settings
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move(
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"$tmp_folder/master-postgresql.conf.tmp",
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"$master_pgdata/postgresql.conf");
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# Plug-in rewound node to the now-promoted standby node
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my $port_standby = $node_standby->port;
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$node_master->append_conf(
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'recovery.conf', qq(
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primary_conninfo='port=$port_standby'
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standby_mode=on
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recovery_target_timeline='latest'
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));
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# Restart the master to check that rewind went correctly
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$node_master->start;
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#### Now run the test-specific parts to check the result
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}
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# Clean up after the test. Stop both servers, if they're still running.
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sub clean_rewind_test
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{
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$node_master->teardown_node if defined $node_master;
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$node_standby->teardown_node if defined $node_standby;
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}
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1;
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