From: Drouvot, Bertrand <bertranddrouvot.pg@gmail.com>
To: Noah Misch <noah@leadboat.com>
To: Andres Freund <andres@anarazel.de>
Cc: Amit Kapila <amit.kapila16@gmail.com>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>
Cc: Jeff Davis <pgsql@j-davis.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@gmail.com>
Cc: Ibrar Ahmed <ibrar.ahmad@gmail.com>
Cc: Amit Khandekar <amitdkhan.pg@gmail.com>
Cc: fabriziomello@gmail.com, tushar <tushar.ahuja@enterprisedb.com>
Cc: Rahila Syed <rahila.syed@2ndquadrant.com>
Cc: pgsql-hackers <pgsql-hackers@postgresql.org>
Subject: Re: Minimal logical decoding on standbys
Date: Tue, 11 Apr 2023 10:55:43 +0200
Message-ID: <e217cdaf-53a1-6d41-59e2-4f4a8bbe9f23@gmail.com> (raw)
In-Reply-To: <7eb26a22-a6b2-f938-6d3c-6adcf4785004@gmail.com>
References: <1903ca9b-1dc9-20a6-404a-d4c460c7bdcc@gmail.com>
<CAA4eK1KFrxgQJt7kc-_o5ruLvafw_FR=NUizA8A7Bp1TDOEj8g@mail.gmail.com>
<2b002763-f39f-0814-e98e-c48989ddc3c3@gmail.com>
<3c9d4998-a338-081f-a5f6-d038ead75384@gmail.com>
<20230407055618.33gjg5vd5hq3kje4@awork3.anarazel.de>
<71c3d91a-6b3b-5c0a-ffb9-630f17fe693e@gmail.com>
<20230407075009.igg7be27ha2htkbt@awork3.anarazel.de>
<1e923731-ed09-3621-c8b9-61f938b4c355@gmail.com>
<20230407154757.ywqnldz4nsycap3g@awork3.anarazel.de>
<20230407181226.6oyt4jcazy6eh7rx@awork3.anarazel.de>
<20230411053657.GA1177147@rfd.leadboat.com>
<7eb26a22-a6b2-f938-6d3c-6adcf4785004@gmail.com>
Hi,
On 4/11/23 10:20 AM, Drouvot, Bertrand wrote:
> Hi,
>
> On 4/11/23 7:36 AM, Noah Misch wrote:
>> On Fri, Apr 07, 2023 at 11:12:26AM -0700, Andres Freund wrote:
>>> --- /dev/null
>>> +++ b/src/test/recovery/t/035_standby_logical_decoding.pl
>>> @@ -0,0 +1,720 @@
>>> +# logical decoding on standby : test logical decoding,
>>> +# recovery conflict and standby promotion.
>> ...
>>> +$node_primary->append_conf('postgresql.conf', q{
>>> +wal_level = 'logical'
>>> +max_replication_slots = 4
>>> +max_wal_senders = 4
>>> +log_min_messages = 'debug2'
>>> +log_error_verbosity = verbose
>>> +});
>>
>> Buildfarm member hoverfly stopped reporting in when this test joined the tree.
>> It's currently been stuck here for 140 minutes:
>>
>
> Thanks for the report!
>
> It's looping on:
>
> 2023-04-11 02:57:52.516 UTC [62718288:5] 035_standby_logical_decoding.pl LOG: 00000: statement: SELECT restart_lsn IS NOT NULL
> FROM pg_catalog.pg_replication_slots WHERE slot_name = 'promotion_inactiveslot'
>
> And the reason is that the slot is not being created:
>
> $ grep "CREATE_REPLICATION_SLOT" 035_standby_logical_decoding_standby.log | tail -2
> 2023-04-11 02:57:47.287 UTC [9241178:15] 035_standby_logical_decoding.pl STATEMENT: CREATE_REPLICATION_SLOT "otherslot" LOGICAL "test_decoding" ( SNAPSHOT 'nothing')
> 2023-04-11 02:57:47.622 UTC [9241178:23] 035_standby_logical_decoding.pl STATEMENT: CREATE_REPLICATION_SLOT "otherslot" LOGICAL "test_decoding" ( SNAPSHOT 'nothing')
>
> Not sure why the slot is not being created.
>
> There is also "replication apply delay" increasing:
>
> 2023-04-11 02:57:49.183 UTC [13304488:253] DEBUG: 00000: sendtime 2023-04-11 02:57:49.111363+00 receipttime 2023-04-11 02:57:49.183512+00 replication apply delay 644 ms transfer latency 73 ms
> 2023-04-11 02:57:49.184 UTC [13304488:259] DEBUG: 00000: sendtime 2023-04-11 02:57:49.183461+00 receipttime 2023-04-11 02:57:49.1842+00 replication apply delay 645 ms transfer latency 1 ms
> 2023-04-11 02:57:49.221 UTC [13304488:265] DEBUG: 00000: sendtime 2023-04-11 02:57:49.184166+00 receipttime 2023-04-11 02:57:49.221059+00 replication apply delay 682 ms transfer latency 37 ms
> 2023-04-11 02:57:49.222 UTC [13304488:271] DEBUG: 00000: sendtime 2023-04-11 02:57:49.221003+00 receipttime 2023-04-11 02:57:49.222144+00 replication apply delay 683 ms transfer latency 2 ms
> 2023-04-11 02:57:49.222 UTC [13304488:277] DEBUG: 00000: sendtime 2023-04-11 02:57:49.222095+00 receipttime 2023-04-11 02:57:49.2228+00 replication apply delay 684 ms transfer latency 1 ms
>
> Noah, I think hoverfly is yours, would it be possible to have access (I'm not an AIX expert though) or check if you see a slot creation hanging and if so why?
>
Well, we can see in 035_standby_logical_decoding_standby.log:
2023-04-11 02:57:49.180 UTC [62718258:5] [unknown] FATAL: 3D000: database "testdb" does not exist
While, on the primary:
2023-04-11 02:57:48.505 UTC [62718254:5] 035_standby_logical_decoding.pl LOG: 00000: statement: CREATE DATABASE testdb
The TAP test is doing:
"
##################################################
# Test standby promotion and logical decoding behavior
# after the standby gets promoted.
##################################################
$node_standby->reload;
$node_primary->psql('postgres', q[CREATE DATABASE testdb]);
$node_primary->safe_psql('testdb', qq[CREATE TABLE decoding_test(x integer, y text);]);
# create the logical slots
create_logical_slots($node_standby, 'promotion_');
"
I think we might want to add:
$node_primary->wait_for_replay_catchup($node_standby);
before calling the slot creation.
It's done in the attached, would it be possible to give it a try please?
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.comdiff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.plindex ba98a18bd2..ad845aee28 100644--- a/src/test/recovery/t/035_standby_logical_decoding.pl+++ b/src/test/recovery/t/035_standby_logical_decoding.pl@@ -653,6 +653,9 @@ $node_standby->reload;
$node_primary->psql('postgres', q[CREATE DATABASE testdb]);
$node_primary->safe_psql('testdb', qq[CREATE TABLE decoding_test(x integer, y text);]);
+# Wait for the standby to catchup before creating the slots+$node_primary->wait_for_replay_catchup($node_standby);+
# create the logical slots
create_logical_slots($node_standby, 'promotion_');
Attachments:
[text/plain] hoverfly.patch (667B, ../e217cdaf-53a1-6d41-59e2-4f4a8bbe9f23@gmail.com/2-hoverfly.patch)
download | inline diff:diff --git a/src/test/recovery/t/035_standby_logical_decoding.pl b/src/test/recovery/t/035_standby_logical_decoding.plindex ba98a18bd2..ad845aee28 100644--- a/src/test/recovery/t/035_standby_logical_decoding.pl+++ b/src/test/recovery/t/035_standby_logical_decoding.pl@@ -653,6 +653,9 @@ $node_standby->reload;
$node_primary->psql('postgres', q[CREATE DATABASE testdb]);
$node_primary->safe_psql('testdb', qq[CREATE TABLE decoding_test(x integer, y text);]);
+# Wait for the standby to catchup before creating the slots+$node_primary->wait_for_replay_catchup($node_standby);+
# create the logical slots
create_logical_slots($node_standby, 'promotion_');
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To: pgsql-hackers@postgresql.org
Cc: bertranddrouvot.pg@gmail.com, noah@leadboat.com, andres@anarazel.de, amit.kapila16@gmail.com, alvherre@alvh.no-ip.org, pgsql@j-davis.com, robertmhaas@gmail.com, thomas.munro@gmail.com, ibrar.ahmad@gmail.com, amitdkhan.pg@gmail.com, tushar.ahuja@enterprisedb.com, rahila.syed@2ndquadrant.com
Subject: Re: Minimal logical decoding on standbys
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