From: | Boszormenyi Zoltan <zb(at)cybertec(dot)at> |
---|---|
To: | Martijn van Oosterhout <kleptog(at)svana(dot)org> |
Cc: | Bernd Helmle <mailings(at)oopsware(dot)de>, pgsql-hackers(at)postgresql(dot)org, Hans-Juergen Schoenig <hs(at)cybertec(dot)at> |
Subject: | Re: pg_ctl stop -m immediate on the primary server inflates sequences |
Date: | 2010-04-12 08:07:17 |
Message-ID: | 4BC2D4B5.9090400@cybertec.at |
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Lists: | pgsql-hackers |
Martijn van Oosterhout írta:
> On Sat, Apr 10, 2010 at 02:36:41PM +0200, Boszormenyi Zoltan wrote:
>
>>>> The above is quite reproducable, "pg_ctl stop -m immediate"
>>>> "usually" inflated my serial sequence, but I had two occasions
>>>> when not. The 69 -> 70 was one. The inflated increase is always 33:
>>>>
>>> AFAIKS sequences are pre-logged with 32 values to WAL to avoid
>>> overhead. I suspect this is why you are seeing those gaps.
>>>
>> Then it should happen all the time, even with "-m fast" or "-m smart", no?
>>
>
> Nope, because on a normal shutdown it writes out the actual value. When
> you say "immediate" you mean "right now, don't bother with anything not
> important", like for example gaps in sequences. You're essentially
> crashing the DB.
>
> Have a ncie day,
>
OK, thanks for the info.
--
Bible has answers for everything. Proof:
"But let your communication be, Yea, yea; Nay, nay: for whatsoever is more
than these cometh of evil." (Matthew 5:37) - basics of digital technology.
"May your kingdom come" - superficial description of plate tectonics
----------------------------------
Zoltán Böszörményi
Cybertec Schönig & Schönig GmbH
http://www.postgresql.at/
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