Refactor background psql TAP functions

This breaks out the background and interactive psql functionality into a
new class, PostgreSQL::Test::BackgroundPsql.  Sessions are still initiated
via PostgreSQL::Test::Cluster, but once started they can be manipulated by
the new helper functions which intend to make querying easier.  A sample
session for a command which can be expected to finish at a later time can
be seen below.

  my $session = $node->background_psql('postgres');
  $bsession->query_until(qr/start/, q(
    \echo start
	CREATE INDEX CONCURRENTLY idx ON t(a);
  ));
  $bsession->quit;

Patch by Andres Freund with some additional hacking by me.

Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/20230130194350.zj5v467x4jgqt3d6@awork3.anarazel.de

1 files changed, 23 insertions, 47 deletions

diff --git a/contrib/amcheck/t/003_cic_2pc.pl b/contrib/amcheck/t/003_cic_2pc.pl
index eabe6fcf96..5323ed11ae 100644
--- a/contrib/amcheck/t/003_cic_2pc.pl
+++ b/contrib/amcheck/t/003_cic_2pc.pl
@@ -36,63 +36,46 @@ $node->safe_psql('postgres', q(CREATE TABLE tbl(i int)));
 # statements.
 #
 
-my $main_in    = '';
-my $main_out   = '';
-my $main_timer = IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-
-my $main_h =
-  $node->background_psql('postgres', \$main_in, \$main_out,
-	$main_timer, on_error_stop => 1);
-$main_in .= q(
+my $main_h = $node->background_psql('postgres');
+
+$main_h->query_safe(q(
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint1
-);
-pump $main_h until $main_out =~ /syncpoint1/ || $main_timer->is_expired;
-
-my $cic_in    = '';
-my $cic_out   = '';
-my $cic_timer = IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-my $cic_h =
-  $node->background_psql('postgres', \$cic_in, \$cic_out,
-	$cic_timer, on_error_stop => 1);
-$cic_in .= q(
+));
+
+my $cic_h = $node->background_psql('postgres');
+
+$cic_h->query_until(qr/start/, q(
 \echo start
 CREATE INDEX CONCURRENTLY idx ON tbl(i);
-);
-pump $cic_h until $cic_out =~ /start/ || $cic_timer->is_expired;
+));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'a';
-);
+));
 
-$main_in .= q(
+$main_h->query_safe(q(
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint2
-);
-pump $main_h until $main_out =~ /syncpoint2/ || $main_timer->is_expired;
+));
 
 $node->safe_psql('postgres', q(COMMIT PREPARED 'a';));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'b';
 BEGIN;
 INSERT INTO tbl VALUES(0);
-\echo syncpoint3
-);
-pump $main_h until $main_out =~ /syncpoint3/ || $main_timer->is_expired;
+));
 
 $node->safe_psql('postgres', q(COMMIT PREPARED 'b';));
 
-$main_in .= q(
+$main_h->query_safe(q(
 PREPARE TRANSACTION 'c';
 COMMIT PREPARED 'c';
-);
-$main_h->pump_nb;
+));
 
-$main_h->finish;
-$cic_h->finish;
+$main_h->quit;
+$cic_h->quit;
 
 $result = $node->psql('postgres', q(SELECT bt_index_check('idx',true)));
 is($result, '0', 'bt_index_check after overlapping 2PC');
@@ -113,22 +96,15 @@ PREPARE TRANSACTION 'persists_forever';
 ));
 $node->restart;
 
-my $reindex_in  = '';
-my $reindex_out = '';
-my $reindex_timer =
-  IPC::Run::timeout($PostgreSQL::Test::Utils::timeout_default);
-my $reindex_h =
-  $node->background_psql('postgres', \$reindex_in, \$reindex_out,
-	$reindex_timer, on_error_stop => 1);
-$reindex_in .= q(
+my $reindex_h = $node->background_psql('postgres');
+$reindex_h->query_until(qr/start/, q(
 \echo start
 DROP INDEX CONCURRENTLY idx;
 CREATE INDEX CONCURRENTLY idx ON tbl(i);
-);
-pump $reindex_h until $reindex_out =~ /start/ || $reindex_timer->is_expired;
+));
 
 $node->safe_psql('postgres', "COMMIT PREPARED 'spans_restart'");
-$reindex_h->finish;
+$reindex_h->quit;
 $result = $node->psql('postgres', q(SELECT bt_index_check('idx',true)));
 is($result, '0', 'bt_index_check after 2PC and restart');