Re: Logical archiving - Mailing list pgsql-hackers

From Euler Taveira
Subject Re: Logical archiving
Date
Msg-id CAH503wByHS=j0S73O5LujE4tUo28iKLUd9A3CA+VfLLg-KVNCw@mail.gmail.com
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In response to Logical archiving  (Andrey Borodin <x4mmm@yandex-team.ru>)
Responses Re: Logical archiving
List pgsql-hackers
On Fri, 4 Dec 2020 at 04:33, Andrey Borodin <x4mmm@yandex-team.ru> wrote:

I was discussing problems of CDC with scientific community and they asked this simple question: "So you have efficient WAL archive on a very cheap storage, why don't you have a logical archive too?"

WAL archive doesn't process data; it just copies from one location into another one. However, "logical archive" must process data.
 
If we could just run archive command ```archive-tool wal-push 0000000900000F2C000000E1.logical``` with contents of logical replication - this would be super cool for OLAP. I'd prefer even avoid writing 0000000900000F2C000000E1.logical to disk, i.e. push data on stdio or something like that.

The most time consuming process is logical decoding, mainly due to long running transactions. In order to minimize your issue, we should improve the logical decoding mechanism. There was a discussion about allowing logical decoding on the replica that would probably help your use case a lot.


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Euler Taveira                 http://www.2ndQuadrant.com/
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