From 209a72b703ea6234df5fcecd2eff65a3f9d7a72b Mon Sep 17 00:00:00 2001 From: Kyotaro Horiguchi Date: Thu, 21 Dec 2017 17:33:53 +0900 Subject: [PATCH 4/6] TAP test for the slot limit feature --- src/test/recovery/t/016_replslot_limit.pl | 184 ++++++++++++++++++++++ 1 file changed, 184 insertions(+) create mode 100644 src/test/recovery/t/016_replslot_limit.pl diff --git a/src/test/recovery/t/016_replslot_limit.pl b/src/test/recovery/t/016_replslot_limit.pl new file mode 100644 index 0000000000..e150ca7a54 --- /dev/null +++ b/src/test/recovery/t/016_replslot_limit.pl @@ -0,0 +1,184 @@ +# Test for replication slot limit +# Ensure that max_slot_wal_keep_size limits the number of WAL files to +# be kept by replication slots. + +use strict; +use warnings; +use File::Path qw(rmtree); +use PostgresNode; +use TestLib; +use Test::More tests => 11; +use Time::HiRes qw(usleep); + +$ENV{PGDATABASE} = 'postgres'; + +# Initialize master node, setting wal-segsize to 1MB +my $node_master = get_new_node('master'); +$node_master->init(allows_streaming => 1, extra => ['--wal-segsize=1']); +$node_master->append_conf('postgresql.conf', qq( +min_wal_size = 2MB +max_wal_size = 3MB +)); +$node_master->start; +$node_master->safe_psql('postgres', "SELECT pg_create_physical_replication_slot('rep1')"); + +# The slot state should be the state "unknown" before the first connection +my $result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "|unknown|0", 'check the state of non-reserved slot is "unknown"'); + + +# Take backup +my $backup_name = 'my_backup'; +$node_master->backup($backup_name); + +# Create a standby linking to it using the replication slot +my $node_standby = get_new_node('standby_1'); +$node_standby->init_from_backup($node_master, $backup_name, has_streaming => 1, primary_slot_name => 'rep1'); + +$node_standby->start; + +# Wait until standby has replayed enough data +my $start_lsn = $node_master->lsn('write'); +$node_master->wait_for_catchup($node_standby, 'replay', $start_lsn); + +# Stop standby +$node_standby->stop; + + +# Preparation done, the slot is the state "streaming" now +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|streaming|0", 'check the catching-up state'); + +# Advance WAL by five segments (= 5MB) on master +advance_wal($node_master, 5); +$node_master->safe_psql('postgres', "CHECKPOINT;"); + +# The slot is always "safe" when max_slot_wal_keep_size is not set +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|streaming|0", 'check that slot is working'); + +# The standby can connect to master +$node_standby->start; + +$start_lsn = $node_master->lsn('write'); +$node_master->wait_for_catchup($node_standby, 'replay', $start_lsn); + +$node_standby->stop; + +# Set max_slot_wal_keep_size on master +my $max_slot_wal_keep_size_mb = 3; +$node_master->append_conf('postgresql.conf', qq( +max_slot_wal_keep_size = ${max_slot_wal_keep_size_mb}MB +)); +$node_master->reload; + +# The slot is in safe state. The remaining bytes should be as almost +# (max_slot_wal_keep_size + 1) times large as the segment size +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, pg_size_pretty(remain) as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|streaming|4096 kB", 'check that max_slot_wal_keep_size is working'); + +# Advance WAL again then checkpoint +advance_wal($node_master, 2); +$node_master->safe_psql('postgres', "CHECKPOINT;"); + +# The slot is still working. +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, pg_size_pretty(remain) as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|streaming|2048 kB", 'check that remaining byte is calculated correctly'); + +# wal_keep_segments overrides max_slot_wal_keep_size +$result = $node_master->safe_psql('postgres', "ALTER SYSTEM SET wal_keep_segments to 6; SELECT pg_reload_conf();"); +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, pg_size_pretty(remain) as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|streaming|5120 kB", 'check that wal_keep_segments overrides max_slot_wal_keep_size'); + +# restore wal_keep_segments +$result = $node_master->safe_psql('postgres', "ALTER SYSTEM SET wal_keep_segments to 0; SELECT pg_reload_conf();"); + +# Advance WAL again without checkpoint +advance_wal($node_master, 2); + +# Slot gets to 'keeping' state +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, pg_size_pretty(remain) as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|keeping|0 bytes", 'check that the slot state changes to "keeping"'); + +# The standby still can connect to master +$node_standby->start; + +$start_lsn = $node_master->lsn('write'); +$node_master->wait_for_catchup($node_standby, 'replay', $start_lsn); + +$node_standby->stop; + +ok(!find_in_log($node_standby, + "requested WAL segment [0-9A-F]+ has already been removed"), + 'check that required WAL segments are still available'); + +# Advance WAL again, the slot loses some segments. +my $logstart = get_log_size($node_master); +advance_wal($node_master, 5); +$node_master->safe_psql('postgres', "CHECKPOINT;"); + +# WARNING should be issued +ok(find_in_log($node_master, + "some replication slots have lost required WAL segments\n". + ".*Slot rep1 lost 2 segment\\(s\\)\\.", + $logstart), + 'check that the warning is logged'); + +# This slot should be broken +$result = $node_master->safe_psql('postgres', "SELECT restart_lsn, wal_status, pg_size_pretty(remain) as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"); +is($result, "$start_lsn|lost|0 bytes", 'check that the slot state changes to "lost"'); + +# The standby no longer can connect to the master +$logstart = get_log_size($node_standby); +$node_standby->start; + +my $failed = 0; +for (my $i = 0 ; $i < 10000 ; $i++) +{ + if (find_in_log($node_standby, + "requested WAL segment [0-9A-F]+ has already been removed", + $logstart)) + { + $failed = 1; + last; + } + usleep(100_000); +} +ok($failed, 'check that replication has been broken'); + +$node_standby->stop; + +##################################### +# Advance WAL of $node by $n segments +sub advance_wal +{ + my ($node, $n) = @_; + + # Advance by $n segments (= (16 * $n) MB) on master + for (my $i = 0 ; $i < $n ; $i++) + { + $node->safe_psql('postgres', "CREATE TABLE t (); DROP TABLE t; SELECT pg_switch_wal();"); + } +} + +# return the size of logfile of $node in bytes +sub get_log_size +{ + my ($node) = @_; + + return (stat $node->logfile)[7]; +} + +# find $pat in logfile of $node after $off-th byte +sub find_in_log +{ + my ($node, $pat, $off) = @_; + + $off = 0 unless defined $off; + my $log = TestLib::slurp_file($node->logfile); + return 0 if (length($log) <= $off); + + $log = substr($log, $off); + + return $log =~ m/$pat/; +} -- 2.20.1