On Tue, Dec 19, 2023 at 9:51 AM Michael Paquier <mich...@paquier.xyz> wrote:
>
> On Mon, Dec 18, 2023 at 08:48:09AM -0300, Euler Taveira wrote:
> > It is cheaper.
>
> Agreed that this could just use a set of pg_logical_emit_message()
> when jumping across N segments.
Thanks. I missed the point of using pg_logical_emit_message() over
CREATE .. DROP TABLE to generate WAL. And, I agree that it's better
and relatively cheaper in terms of amount of WAL generated.
> Another thing that seems quite
> important to me is to force a flush of WAL with the last segment
> switch, and the new "flush" option of pg_logical_emit_message() can
> be very handy for this purpose.
I used pg_logical_emit_message() in non-transactional mode without
needing an explicit WAL flush as the pg_switch_wal() does a WAL flush
at the end [1].
Attached v4 patch.
[1]
/*
* If this was an XLOG_SWITCH record, flush the record and the empty
* padding space that fills the rest of the segment, and perform
* end-of-segment actions (eg, notifying archiver).
*/
if (class == WALINSERT_SPECIAL_SWITCH)
{
TRACE_POSTGRESQL_WAL_SWITCH();
XLogFlush(EndPos);
--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
From b7fa7545eb983aaf92e3d7e99bdf76ef42b8e40e Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Tue, 19 Dec 2023 05:49:20 +0000
Subject: [PATCH v4] Add a TAP test function to generate WAL
This commit adds a perl function in Cluster.pm to generate WAL.
Some TAP tests are now using their own way to generate WAL.
Generalizing this functionality enables multiple TAP tests to
reuse the functionality.
---
src/test/perl/PostgreSQL/Test/Cluster.pm | 22 +++++++++
src/test/recovery/t/001_stream_rep.pl | 6 +--
src/test/recovery/t/019_replslot_limit.pl | 48 +++++--------------
.../t/035_standby_logical_decoding.pl | 7 +--
4 files changed, 38 insertions(+), 45 deletions(-)
diff --git a/src/test/perl/PostgreSQL/Test/Cluster.pm b/src/test/perl/PostgreSQL/Test/Cluster.pm
index a020377761..ad575ed6d6 100644
--- a/src/test/perl/PostgreSQL/Test/Cluster.pm
+++ b/src/test/perl/PostgreSQL/Test/Cluster.pm
@@ -3178,6 +3178,28 @@ sub create_logical_slot_on_standby
=pod
+=item $node->advance_wal($n)
+
+Advance WAL of given node by $n segments
+
+=cut
+
+sub advance_wal
+{
+ my ($self, $n) = @_;
+
+ # Advance by $n segments (= (wal_segment_size * $n) bytes).
+ for (my $i = 0; $i < $n; $i++)
+ {
+ $self->safe_psql('postgres', qq{
+ SELECT pg_logical_emit_message(false, '', 'foo');
+ SELECT pg_switch_wal();
+ });
+ }
+}
+
+=pod
+
=back
=cut
diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl
index 95f9b0d772..f0de921b4b 100644
--- a/src/test/recovery/t/001_stream_rep.pl
+++ b/src/test/recovery/t/001_stream_rep.pl
@@ -522,11 +522,7 @@ $node_primary->safe_psql('postgres',
my $segment_removed = $node_primary->safe_psql('postgres',
'SELECT pg_walfile_name(pg_current_wal_lsn())');
chomp($segment_removed);
-$node_primary->psql(
- 'postgres', "
- CREATE TABLE tab_phys_slot (a int);
- INSERT INTO tab_phys_slot VALUES (generate_series(1,10));
- SELECT pg_switch_wal();");
+$node_primary->advance_wal(1);
my $current_lsn =
$node_primary->safe_psql('postgres', "SELECT pg_current_wal_lsn();");
chomp($current_lsn);
diff --git a/src/test/recovery/t/019_replslot_limit.pl b/src/test/recovery/t/019_replslot_limit.pl
index 7d94f15778..e4b75c6545 100644
--- a/src/test/recovery/t/019_replslot_limit.pl
+++ b/src/test/recovery/t/019_replslot_limit.pl
@@ -59,7 +59,7 @@ $result = $node_primary->safe_psql('postgres',
is($result, "reserved|t", 'check the catching-up state');
# Advance WAL by five segments (= 5MB) on primary
-advance_wal($node_primary, 1);
+$node_primary->advance_wal(1);
$node_primary->safe_psql('postgres', "CHECKPOINT;");
# The slot is always "safe" when fitting max_wal_size
@@ -69,7 +69,7 @@ $result = $node_primary->safe_psql('postgres',
is($result, "reserved|t",
'check that it is safe if WAL fits in max_wal_size');
-advance_wal($node_primary, 4);
+$node_primary->advance_wal(4);
$node_primary->safe_psql('postgres', "CHECKPOINT;");
# The slot is always "safe" when max_slot_wal_keep_size is not set
@@ -100,7 +100,7 @@ $result = $node_primary->safe_psql('postgres',
is($result, "reserved", 'check that max_slot_wal_keep_size is working');
# Advance WAL again then checkpoint, reducing remain by 2 MB.
-advance_wal($node_primary, 2);
+$node_primary->advance_wal(2);
$node_primary->safe_psql('postgres', "CHECKPOINT;");
# The slot is still working
@@ -118,7 +118,7 @@ $node_standby->stop;
$result = $node_primary->safe_psql('postgres',
"ALTER SYSTEM SET wal_keep_size to '8MB'; SELECT pg_reload_conf();");
# Advance WAL again then checkpoint, reducing remain by 6 MB.
-advance_wal($node_primary, 6);
+$node_primary->advance_wal(6);
$result = $node_primary->safe_psql('postgres',
"SELECT wal_status as remain FROM pg_replication_slots WHERE slot_name = 'rep1'"
);
@@ -134,7 +134,7 @@ $node_primary->wait_for_catchup($node_standby);
$node_standby->stop;
# Advance WAL again without checkpoint, reducing remain by 6 MB.
-advance_wal($node_primary, 6);
+$node_primary->advance_wal(6);
# Slot gets into 'reserved' state
$result = $node_primary->safe_psql('postgres',
@@ -145,7 +145,7 @@ is($result, "extended", 'check that the slot state changes to "extended"');
$node_primary->safe_psql('postgres', "CHECKPOINT;");
# Advance WAL again without checkpoint; remain goes to 0.
-advance_wal($node_primary, 1);
+$node_primary->advance_wal(1);
# Slot gets into 'unreserved' state and safe_wal_size is negative
$result = $node_primary->safe_psql('postgres',
@@ -174,7 +174,7 @@ $node_primary->safe_psql('postgres',
# Advance WAL again. The slot loses the oldest segment by the next checkpoint
my $logstart = -s $node_primary->logfile;
-advance_wal($node_primary, 7);
+$node_primary->advance_wal(7);
# Now create another checkpoint and wait until the WARNING is issued
$node_primary->safe_psql('postgres',
@@ -275,18 +275,11 @@ $node_standby->init_from_backup($node_primary2, $backup_name,
has_streaming => 1);
$node_standby->append_conf('postgresql.conf', "primary_slot_name = 'rep1'");
$node_standby->start;
-my @result =
- split(
- '\n',
- $node_primary2->safe_psql(
- 'postgres',
- "CREATE TABLE tt();
- DROP TABLE tt;
- SELECT pg_switch_wal();
- CHECKPOINT;
- SELECT 'finished';",
- timeout => $PostgreSQL::Test::Utils::timeout_default));
-is($result[1], 'finished', 'check if checkpoint command is not blocked');
+$node_primary2->advance_wal(1);
+$result = $node_primary2->safe_psql('postgres',
+ "CHECKPOINT; SELECT 'finished';",
+ timeout => $PostgreSQL::Test::Utils::timeout_default);
+is($result, 'finished', 'check if checkpoint command is not blocked');
$node_primary2->stop;
$node_standby->stop;
@@ -372,7 +365,7 @@ $logstart = -s $node_primary3->logfile;
# freeze walsender and walreceiver. Slot will still be active, but walreceiver
# won't get anything anymore.
kill 'STOP', $senderpid, $receiverpid;
-advance_wal($node_primary3, 2);
+$node_primary3->advance_wal(2);
my $msg_logged = 0;
my $max_attempts = $PostgreSQL::Test::Utils::timeout_default;
@@ -418,19 +411,4 @@ kill 'CONT', $receiverpid;
$node_primary3->stop;
$node_standby3->stop;
-#####################################
-# Advance WAL of $node by $n segments
-sub advance_wal
-{
- my ($node, $n) = @_;
-
- # Advance by $n segments (= (wal_segment_size * $n) bytes) on primary.
- for (my $i = 0; $i < $n; $i++)
- {
- $node->safe_psql('postgres',
- "CREATE TABLE t (); DROP TABLE t; SELECT pg_switch_wal();");
- }
- return;
-}
-
done_testing();
diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.pl
index 9c34c0d36c..5d7c278d01 100644
--- a/src/test/recovery/t/035_standby_logical_decoding.pl
+++ b/src/test/recovery/t/035_standby_logical_decoding.pl
@@ -524,11 +524,8 @@ my $walfile_name = $node_primary->safe_psql('postgres',
chomp($walfile_name);
# Generate some activity and switch WAL file on the primary
-$node_primary->safe_psql(
- 'postgres', "create table retain_test(a int);
- select pg_switch_wal();
- insert into retain_test values(1);
- checkpoint;");
+$node_primary->advance_wal(1);
+$node_primary->safe_psql('postgres', "checkpoint;");
# Wait for the standby to catch up
$node_primary->wait_for_replay_catchup($node_standby);
--
2.34.1
