AW: Query performance issue - Mailing list pgsql-performance

From Dirk Krautschick
Subject AW: Query performance issue
Date
Msg-id AM0PR05MB6082CCD956B25336CDAD77C4E9290@AM0PR05MB6082.eurprd05.prod.outlook.com
Whole thread Raw
In response to Re: Query performance issue  (Nagaraj Raj <nagaraj.sf@yahoo.com>)
List pgsql-performance
Hi %,

in order to be able to readjust the effects of the stored procedure and, if necessary, 
to save turnaround times, different requests can be concatenated using semicolons for
bundling several statements in one request. We did some tests against a postgres cluster.

The results in terms of optimizations are as follows:


Batchsize  | clients|  count Queries | average s/query| comment
--------------|---------|----------------------|----------------------|-------------------
1         | 1        |  15.86k         |  2.24ms               | 
10         | 1        |  31.80k         |  332us               | 
25         | 1        |  31.75k         |  312us               | 
50         | 1        |  32.00k         |  280us               | 
100         | 1        |  32.00k         |  286us               | 
          |          |                |                                | 
1         | 2        |  57.1k         |  733us               | Drop to 30k after some time!!
10         | 2        |  63.6k         |  323us               | 
25         | 2        |  63.5k         |  308us               | 
50         | 2        |  64k         |  293us               | 
100         | 2        |  67.2k         |  290us               | 
                   |           |                            |                               | 
1         | 10        |  158.6k         |  2.15ms               |     
10         | 10        |  298.9k         |  383us               | Drop to ~200k!!
25         | 10        |  225k         |  1.16ms               | 
50         | 10        |  192k         |  1.55ms               | 
100         | 10        |  201.6k         |  1.44ms               | 
          |          |                         |                                 | 
10         | 50        |  800k                 |  2.2ms               | 


It seems to be saturated here at around 200k requests per minute, 
the question remains why this is so.

Does anyone has experience with something similar or are there some
hints about how to optimize the postgres cluster for such bundled statements?

Thanks and best regards

Dirk

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