Thread

Re: Performance issues

Oleg Bartunov <oleg@sai.msu.su> — 2011-03-07T15:34:35Z

On Mon, 7 Mar 2011, Andreas For? Tollefsen wrote:

> Ok. Cheers. I will do some more testing on my heavy PostGIS queries which
> often takes hours to complete.

I'd like to see hours long queries :) EXPLAIN ANALYZE

>
> Thanks.
> Andreas
>
> 2011/3/7 Kenneth Marshall <ktm@rice.edu>
>
>> On Mon, Mar 07, 2011 at 03:17:05PM +0100, Andreas For? Tollefsen wrote:
>>> Thanks, Ken.
>>>
>>> It seems like the tip to turn off synchronous_commit did the trick:
>>>
>>> /usr/lib/postgresql/8.4/bin/pgbench -T 60 test1
>>> starting vacuum...end.
>>> transaction type: TPC-B (sort of)
>>> scaling factor: 1
>>> query mode: simple
>>> number of clients: 1
>>> duration: 60 s
>>> number of transactions actually processed: 86048
>>> tps = 1434.123199 (including connections establishing)
>>> tps = 1434.183362 (excluding connections establishing)
>>>
>>> Is this acceptable compared to others when considering my setup?
>>>
>>> Cheers,
>>> Andreas
>>>
>>
>>
>> These are typical results for synchronous_commit off. The caveat
>> is you must be able to handle loosing transactions if you have a
>> database crash, but your database is still intact. This differs
>> from turning fsync off in which a crash means you would need to
>> restore from a backup.
>>
>> Cheers,
>> Ken
>>
>

 	Regards,
 		Oleg
_____________________________________________________________
Oleg Bartunov, Research Scientist, Head of AstroNet (www.astronet.ru),
Sternberg Astronomical Institute, Moscow University, Russia
Internet: oleg@sai.msu.su, http://www.sai.msu.su/~megera/
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