From: Vitalii Tymchyshyn <tivv00@gmail.com>
To: Robert Ayrapetyan <robert.ayrapetyan@comodo.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Performance die when COPYing to table with bigint PK
Date: Tue, 02 Aug 2011 11:42:42 +0300
Message-ID: <4E37B882.8080005@gmail.com> (raw)
In-Reply-To: <CAAboi9s9MCsmqYPR+KqtXstPUodiE5MzvEpk1-e+C0n6FwkkyQ@mail.gmail.com>
References: <CAAboi9sk0EnbS23-tr86X9i7LdHTfdbTP4aa7r2q7NpWKaHWPA@mail.gmail.com>
<4E366C9C.4040904@gmail.com>
<CAAboi9uU+hMg8deuJ6Q2LxncE2HO2jykPW89fPVxHLsU8_tFrw@mail.gmail.com>
<CAAboi9s9MCsmqYPR+KqtXstPUodiE5MzvEpk1-e+C0n6FwkkyQ@mail.gmail.com>
02.08.11 11:26, Robert Ayrapetyan написав(ла):
> Seems this assumption is not right. Just created simple index on
> bigint column - situation with huge performance
> degradation repeated. Dropping this index solved COPY issues on the fly.
> So I'm still convinced - this bug relates to FreeBSD 64-bit + UFS +
> bigint column index
> (some of these may be superfluous, but I have no resources to check on
> different platforms with different filesystems).
Interrrresting. We also have FreeBSDx64 on UFS and are using bigint
(bigserial) keys. It seems I will need to perform more tests here
because I do see similar problems. I for sure can do a copy of data with
int4 keys and test the performance.
BTW: The thing we are going to try on next upgrade is to change UFS
block size from 16K to 8K. What problem I saw is that with default
setting, UFS needs to read additional 8K when postgresql writes it's
page (and for index random writes can be vital). Unfortunately, such a
changes requires partition reformat and I can't afford it for now.
Best regards, Vitalii Tymchyshyn
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Cc: tivv00@gmail.com, robert.ayrapetyan@comodo.com
Subject: Re: Performance die when COPYing to table with bigint PK
In-Reply-To: <4E37B882.8080005@gmail.com>
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