# Verify stats data persistence

use strict;
use warnings;
use PostgresNode;
use TestLib;
use Test::More tests => 6;

my $backup_name = 'my_backup';

# Initialize a test cluster
my $node_primary = get_new_node('primary');
$node_primary->init(allows_streaming => 1);
$node_primary->start;

$node_primary->safe_psql('postgres', 'CREATE TABLE t(); SELECT * from t;');
my $count =
  $node_primary->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '1', "counter is incremented");

# Stas numbers are restored after graceful restart
$node_primary->restart;

$count =
  $node_primary->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '1', "counter is correctly restored");

# Stas numbers are blown away after a crash
$node_primary->stop('immediate');
$node_primary->start;

$count =
  $node_primary->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '0', "counter is reset after crash");

# Create a standby
$node_primary->backup($backup_name);
my $node_standby = get_new_node('standby');
$node_standby->init_from_backup($node_primary, $backup_name,
								has_streaming => 1);
$node_standby->start;

# Stats numbers are initialized to zero
$count =
  $node_standby->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '0', "counter is initialized");

# Stats numbers are incremented also on standby
$node_standby->safe_psql('postgres', 'SELECT * from t;');
$count =
  $node_standby->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '1', "counter is incremented on standby");

# Stas numbers are always blown away even after graceful restart on standby
$node_primary->restart;

$count =
  $node_primary->safe_psql('postgres',
						   'SELECT seq_scan FROM pg_stat_user_tables');
is($count, '0', "counter is reset after restart on standby");