Re: PostgreSQL logical decoder output plugin - unchanged toast data

Hi,

On 2018-08-31 16:55:37 +0200, Georgy Buranov wrote:
> Ok, thank you very much for your explanation,
> 
> maybe I need something else in my case.
> 
> As far as I understand, "On-disk toasted data for tuples from the WAL
> are not guaranteed in any way to be retain", but still, the LATEST
> value for the same cell should exist in postgres (in on-disk toast if
> it is huge, or not).

No, there's absolutely no such guarantee.  The tuple could since have
been deleted, the column could have been updated to non-toasted, the
table could have been dropped, ...


> If I cannot get access to the on-disk toasted data for tuple from the
> WAL, can I have the access to the _latest_ value in this case
> (hopefully I describe it correct)

Again, you can set REPLICA IDENTITY to FULL and it'll be there.

Greetings,

Andres Freund