Horton

Re: Possible bug in logical replication.

Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>

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From: Kyotaro HORIGUCHI <horiguchi.kyotaro@lab.ntt.co.jp>
To: alvherre@2ndquadrant.com
Cc: michael@paquier.xyz, simon@2ndquadrant.com, a.sher@postgrespro.ru, sawada.mshk@gmail.com, k.knizhnik@postgrespro.ru, pgsql-hackers@lists.postgresql.org
Date: 2018-06-22T07:33:12Z
Lists: pgsql-hackers 
Hello.

At Thu, 14 Jun 2018 16:06:43 -0400, Alvaro Herrera <alvherre@2ndquadrant.com> wrote in <20180614200643.3my362zmfiwitrni@alvherre.pgsql>
> Can somebody (Arseny, Konstantin, horiguti, Sawada) please confirm that
> Michaël's commit fixes the reported bug?

pg_advance_replication_slots can advance uninitialized physical
slots and that might not be good. (Logical slots always have
initial invalid values in thw two lsn columns.)

About scanning from restart_lsn in the advancing function, I
think I confirmed that the value always comes from
XLogRecordBuffer.origptr, which comes from ReadRecPtr, not
EndRecPtr, which cannot be on page boundary.

FWIW, as the result, it looks fine for me also regarding the
issue on this thread.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center

Commits

  1. Rewrite comments in replication slot advance implementation

  2. Fix a couple of bugs with replication slot advancing feature

  3. Ability to advance replication slots