Re: Critical errors during logical decoding - Mailing list pgsql-general

From Colin Morelli
Subject Re: Critical errors during logical decoding
Date
Msg-id CAPtU-Urs_=Y14wN7bgF2gyShp5vT=rTvRCCP9LyMQbkmTv7WOA@mail.gmail.com
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In response to Re: Critical errors during logical decoding  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
Responses Re: Critical errors during logical decoding  (Tomas Vondra <tomas.vondra@2ndquadrant.com>)
List pgsql-general
Hey Tomas,

We're using v1.1.0 of pglogical. I can't honestly say what could reproduce this issue as I'm not entirely sure and haven't tested it yet.

I had thought it was caused when a toasted row is deleted before the pglogical_output plugin processes the event (so it fails when going to de-toast the row), but I would imagine that postgres internally should prevent deleting data that would be needed by a replication stream. I must admit I'm not well versed in this area, though. My understanding is wal2json doesn't detoast the data at all, and thus doesn't have an issue (for our case, we really just need the json data with an identifier telling us that the row changed, we're not doing full logical replication).

Best,
Colin

On Wed, Feb 7, 2018 at 4:18 PM, Tomas Vondra <tomas.vondra@2ndquadrant.com> wrote:
On 02/07/2018 09:07 PM, Colin Morelli wrote:
> Appears to be a problem with pglogical_output when de-toasting columns.
> Switched to wal2json and the problem went away. I believe I may have
> found the issue anyway. Apologies for the noise.
>

What pglogical version are you using? Can you share an example of data
causing this issue (or even better a script reproducing it)?

regards

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

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