Re: Logical Replication WIP

On 19/12/16 08:04, Erik Rijkers wrote:
> On 2016-12-18 11:12, Petr Jelinek wrote:
>
> (now using latest: patchset:)
>
> 0001-Add-PUBLICATION-catalogs-and-DDL-v14.patch
> 0002-Add-SUBSCRIPTION-catalog-and-DDL-v14.patch
> 0003-Define-logical-replication-protocol-and-output-plugi-v14.patch
> 0004-Add-logical-replication-workers-v14.patch
> 0005-Add-separate-synchronous-commit-control-for-logical--v14.patch
>
>> BTW you don't need to add primary key to pgbench_history. Simply ALTER
>> TABLE pgbench_history REPLICA IDENTITY FULL; should be enough.
>
> Either should, but neither is.
>
> set-up:
> Before creating the publication/subscription:
> On master I run pgbench -qis 1, then set replica identity (and/or add
> serial column) for pgbench_history, then dump/restore the 4 pgbench
> tables from master to replica.
> Then enabling publication/subscription. logs looks well. (Other tests
> I've devised earlier (on other tables) still work nicely.)
>
> Now when I do a pgbench-run on master, something like:
>
> pgbench -c 1 -T 20 -P 1
>
> I often see this (when running pgbench):
>
> ERROR: publisher does not send replica identity column expected by the
> logical replication target public.pgbench_tellers
> or, sometimes (less often) the same ERROR for pgbench_accounts appears
> (as in the subsciber-log below)
>
> -- publisher log
> 2016-12-19 07:44:22.738 CET 22690 LOG: logical decoding found
> consistent point at 0/14598C78
> 2016-12-19 07:44:22.738 CET 22690 DETAIL: There are no running
> transactions.
> 2016-12-19 07:44:22.738 CET 22690 LOG: exported logical decoding
> snapshot: "000130FA-1" with 0 transaction IDs
> 2016-12-19 07:44:22.886 CET 22729 LOG: starting logical decoding for
> slot "sub1"
> 2016-12-19 07:44:22.886 CET 22729 DETAIL: streaming transactions
> committing after 0/14598CB0, reading WAL from 0/14598C78
> 2016-12-19 07:44:22.886 CET 22729 LOG: logical decoding found
> consistent point at 0/14598C78
> 2016-12-19 07:44:22.886 CET 22729 DETAIL: There are no running
> transactions.
> 2016-12-19 07:45:25.568 CET 22729 LOG: could not receive data from
> client: Connection reset by peer
> 2016-12-19 07:45:25.568 CET 22729 LOG: unexpected EOF on standby
> connection
> 2016-12-19 07:45:25.580 CET 26696 LOG: starting logical decoding for
> slot "sub1"
> 2016-12-19 07:45:25.580 CET 26696 DETAIL: streaming transactions
> committing after 0/1468E0D0, reading WAL from 0/1468DC90
> 2016-12-19 07:45:25.589 CET 26696 LOG: logical decoding found
> consistent point at 0/1468DC90
> 2016-12-19 07:45:25.589 CET 26696 DETAIL: There are no running
> transactions.
>
> -- subscriber log
> 2016-12-19 07:44:22.878 CET 17027 LOG: starting logical replication
> worker for subscription 24581
> 2016-12-19 07:44:22.883 CET 22726 LOG: logical replication apply for
> subscription sub1 started
> 2016-12-19 07:45:11.069 CET 22726 WARNING: leaked hash_seq_search scan
> for hash table 0x2def1a8
> 2016-12-19 07:45:25.566 CET 22726 ERROR: publisher does not send
> replica identity column expected by the logical replication target
> public.pgbench_accounts
> 2016-12-19 07:45:25.568 CET 16984 LOG: worker process: logical
> replication worker 24581 (PID 22726) exited with exit code 1
> 2016-12-19 07:45:25.568 CET 17027 LOG: starting logical replication
> worker for subscription 24581
> 2016-12-19 07:45:25.574 CET 26695 LOG: logical replication apply for
> subscription sub1 started
> 2016-12-19 07:46:10.950 CET 26695 WARNING: leaked hash_seq_search scan
> for hash table 0x2def2c8
> 2016-12-19 07:46:10.950 CET 26695 WARNING: leaked hash_seq_search scan
> for hash table 0x2def2c8
> 2016-12-19 07:46:10.950 CET 26695 WARNING: leaked hash_seq_search scan
> for hash table 0x2def2c8
>
>
> Sometimes replication (caused by a pgbench run) runs for a few seconds
> replicating all 4 pgbench tables correctly, but never longer than 10 to
> 20 seconds.
>
> If you cannot reproduce with the provided info it I will make a more
> precise setup-desciption, but it's so solidly failing here that I hope
> that won't be necessary.
>

Hi,

nope can't reproduce that. I can reproduce the leaked hash_seq_search.
The attached fixes that. But no issues with replication itself.

The error basically means that pkey on publisher and subscriber isn't
the same.

--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services