Subject: Re: logical decoding / rewrite map vs. maxAllocatedDescs
To: Andres Freund <andres@anarazel.de>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>,
 PostgreSQL-development <pgsql-hackers@postgresql.org>
References: <20180809174746.aa6rbpsu4zjipzif@alvherre.pgsql>
 <b346c3eb-0e65-29ec-47db-0d9a46feaa2c@2ndquadrant.com>
 <20180810211340.nlgyfa7jlmkjcs5m@alap3.anarazel.de>
 <470adb65-5101-4659-d213-41bde1eef8f2@2ndquadrant.com>
 <0328ccdf-17d6-911b-ae35-c6dc4c76708a@2ndquadrant.com>
 <20180811073415.laximmjm4d67rxuh@alap3.anarazel.de>
From: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Message-ID: <fe5f8e53-08c2-3e09-8595-86242b325e9e@2ndquadrant.com>
Date: Sat, 11 Aug 2018 15:11:19 +0200
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On 08/11/2018 09:34 AM, Andres Freund wrote:
> Hi,
> 
> On 2018-08-11 01:55:43 +0200, Tomas Vondra wrote:
>> On 08/10/2018 11:59 PM, Tomas Vondra wrote:
>>>
>>> ...
>>>
>>> I suspect there's some other ingredient, e.g. some manipulation with the
>>> subscription. Or maybe it's not needed at all and I'm just imagining things.
>>>
>>
>> Indeed, the manipulation with the subscription seems to be the key here.
>> I pretty reliably get the 'could not read block' error when doing this:
>>
>> 1) start the insert pgbench
>>
>>    pgbench -n -c 4 -T 300 -p 5433 -f insert.sql test
>>
>> 2) start the vacuum full pgbench
>>
>>    pgbench -n -f vacuum.sql -T 300 -p 5433 test
> 
> Just to be clear: 5433 is the subscriber, right? I tried it with both,
> but it's not clear what you meant with either the previous or the this
> email.
> 

Sorry for the confusion, 5433 was the publisher - I reinitialized the
cluster sometime after the initial report, and happened to swap the port
numbers. That is, both pgbench commands run on the publisher, while the
subscriber tries to sync the table (and fails due to duplicate values).

I can reproduce it pretty reliably, although it may take a couple of
sync tries from the subscriber.

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services