Re: UPDATEDs slowing SELECTs in a fully cached database - Mailing list pgsql-performance

From Jeff Janes
Subject Re: UPDATEDs slowing SELECTs in a fully cached database
Date
Msg-id CAMkU=1z2oriZAv4D2hb55+PX=Q5j8dfxpaZpHhGuYic168B18A@mail.gmail.com
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In response to Re: UPDATEDs slowing SELECTs in a fully cached database  (lars <lhofhansl@yahoo.com>)
Responses Re: UPDATEDs slowing SELECTs in a fully cached database
List pgsql-performance
On Wed, Jul 13, 2011 at 3:41 PM, lars <lhofhansl@yahoo.com> wrote:
> On 07/13/2011 11:42 AM, Kevin Grittner wrote:
>>
>> So transactions without an XID *are* sensitive to
>> synchronous_commit.  That's likely a useful clue.
>>
>> How much did it help the run time of the SELECT which followed the
>> UPDATE?
>
> It has surprisingly little impact on the SELECT side:

If your fsync is truly fsyncing, it seems like it should have
considerable effect.

Could you strace with both -ttt and -T, with and without synchronous commit?

Cheers,

Jeff

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