Re: PostgreSQL Parallel Processing ! - Mailing list pgsql-performance

From Tomas Vondra
Subject Re: PostgreSQL Parallel Processing !
Date
Msg-id 31f8d7cae7e7e0044e368d1cec6e7077.squirrel@sq.gransy.com
Whole thread Raw
In response to Re: PostgreSQL Parallel Processing !  (Marti Raudsepp <marti@juffo.org>)
List pgsql-performance
On 27 Leden 2012, 10:06, Marti Raudsepp wrote:
> On Fri, Jan 27, 2012 at 06:31, sridhar bamandlapally
> <sridhar.bn1@gmail.com> wrote:
>> --------------------------------------------------------------------------
>> | Id  | Operation         | Name | Rows  | Bytes | Cost (%CPU)| Time    
>> |
>> --------------------------------------------------------------------------
>> |   0 | SELECT STATEMENT  |      |  7444K|   944M| 16077   (4)| 00:03:13
>> |
>> |   1 |  TABLE ACCESS FULL| EMP  |  7444K|   944M| 16077   (4)| 00:03:13
>> |
>> --------------------------------------------------------------------------
>
> Sorry to take this off topic, but... Seriously, over 3 minutes to read
> 944 MB of data? That's less than 5 MB/s, what's wrong with your
> database? :)

Yes, those results are quite suspicious. There's probably something
interfering with the queries (other queries, different processes, block
cleanout, ...) or maybe this is purely due to caching.

sridhar, run the queries repeatedly and my quess is the difference will
disappear (and the fist query will be a bit faster I guess).

Tomas


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