Back-port a few PostgresNode.pm methods.

The 'lsn' and 'wait_for_catchup' methods only exist in v10 and
higher, but are needed in order to support a test planned test
case for a bug that exists all the way back to v9.6. To minimize
cross-branch differences in the test case, back-port these
methods.

Discussion: http://postgr.es/m/CA+TgmoaG5dmA_8Xc1WvbvftPjtwx5uzkGEHxE7MiJ+im9jynmw@mail.gmail.com

diff --git a/src/test/perl/PostgresNode.pm b/src/test/perl/PostgresNode.pm
index 5c5926559d9ca07799187248c57706a3233b2731..5f5a7d273192957a927e0e4e30250d7a9fea7c7d 100644 (file)
--- a/src/test/perl/PostgresNode.pm
+++ b/src/test/perl/PostgresNode.pm
@@ -1472,6 +1472,89 @@ sub issues_sql_like
 
 =pod
 
+=item $node->lsn(mode)
+
+Look up WAL locations on the server:
+
+ * insert location (master only, error on replica)
+ * write location (master only, error on replica)
+ * flush location (master only, error on replica)
+ * receive location (always undef on master)
+ * replay location (always undef on master)
+
+mode must be specified.
+
+=cut
+
+sub lsn
+{
+   my ($self, $mode) = @_;
+   my %modes = (
+       'insert'  => 'pg_current_xlog_insert_location()',
+       'flush'   => 'pg_current_xlog_flush_location()',
+       'write'   => 'pg_current_xlog_location()',
+       'receive' => 'pg_last_xlog_receive_location()',
+       'replay'  => 'pg_last_xlog_replay_location()');
+
+   $mode = '<undef>' if !defined($mode);
+   die "unknown mode for 'lsn': '$mode', valid modes are "
+     . join(', ', keys %modes)
+     if !defined($modes{$mode});
+
+   my $result = $self->safe_psql('postgres', "SELECT $modes{$mode}");
+   chomp($result);
+   if ($result eq '')
+   {
+       return;
+   }
+   else
+   {
+       return $result;
+   }
+}
+
+=pod
+
+=item $node->wait_for_catchup(standby_name, mode, target_lsn)
+
+Wait for the node with application_name standby_name (usually from node->name)
+until its replication position in pg_stat_replication equals or passes the
+upstream's xlog insert point at the time this function is called. By default
+the replay_location is waited for, but 'mode' may be specified to wait for any
+of sent|write|flush|replay.
+
+If there is no active replication connection from this peer, waits until
+poll_query_until timeout.
+
+Requires that the 'postgres' db exists and is accessible.
+
+target_lsn may be any arbitrary lsn, but is typically $master_node->lsn('insert').
+
+This is not a test. It die()s on failure.
+
+=cut
+
+sub wait_for_catchup
+{
+   my ($self, $standby_name, $mode, $target_lsn) = @_;
+   $mode = defined($mode) ? $mode : 'replay';
+   my %valid_modes = ( 'sent' => 1, 'write' => 1, 'flush' => 1, 'replay' => 1 );
+   die "unknown mode $mode for 'wait_for_catchup', valid modes are " . join(', ', keys(%valid_modes)) unless exists($valid_modes{$mode});
+   # Allow passing of a PostgresNode instance as shorthand
+   if ( blessed( $standby_name ) && $standby_name->isa("PostgresNode") )
+   {
+       $standby_name = $standby_name->name;
+   }
+   die 'target_lsn must be specified' unless defined($target_lsn);
+   print "Waiting for replication conn " . $standby_name . "'s " . $mode . "_location to pass " . $target_lsn . " on " . $self->name . "\n";
+   my $query = qq[SELECT '$target_lsn' <= ${mode}_location FROM pg_catalog.pg_stat_replication WHERE application_name = '$standby_name';];
+   $self->poll_query_until('postgres', $query)
+       or die "timed out waiting for catchup, current position is " . ($self->safe_psql('postgres', $query) || '(unknown)');
+   print "done\n";
+}
+
+=pod
+
 =back
 
 =cut