public inbox for [email protected]  

help / color / mirror / Atom feed

Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2
2+ messages / 2 participants
[nested] [flat]

* Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2
@ 2017-07-19 01:54 fx TATEISHI KOJI <[email protected]>
  2017-07-19 06:46 ` Re: Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2 Albe Laurenz <[email protected]>
  0 siblings, 1 reply; 2+ messages in thread

From: fx TATEISHI KOJI @ 2017-07-19 01:54 UTC (permalink / raw)
  To: pgsql-performance

Issuing exactly the same query as PostgreSQL 8.2.21 and PostgreSQL 9.3.2 will slow the response by 6.4 ms on average.
What could be the cause?
Measurement method is as follows.
・ PostgreSQL 8.2.21 installation
 ★Measurement
・ Export DUMP of PostgreSQL 8.2.21
・ PostgreSQL 8.2.21 uninstallation
・ PostgreSQL 9.3.2 installation
・ Dump import
 ★Measurement

[query]
select
 table4.a as col_0_0_,
 table4.a as col_1_0_,
 table4.a as col_2_0_,
 table4.b as col_0_1_,
 table4.c,
 table4.d
from
 table1,
 table2,
 table3,
 table4 
where
 table1.a=table2.a and
 table1.a="parameter$1" and
 table2.roleid=table3.roleid and
 table3.a="parameter$2" and
 table4.b='3' and
 table2.a=table4.a;


-- 
Sent via pgsql-performance mailing list ([email protected])
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance



^ permalink  raw  reply  [nested|flat] 2+ messages in thread

* Re: Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2
  2017-07-19 01:54 Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2 fx TATEISHI KOJI <[email protected]>
@ 2017-07-19 06:46 ` Albe Laurenz <[email protected]>
  0 siblings, 0 replies; 2+ messages in thread

From: Albe Laurenz @ 2017-07-19 06:46 UTC (permalink / raw)
  To: 'fx TATEISHI KOJI  *EXTERN*' <[email protected]>; pgsql-performance

fx TATEISHI KOJI wrote:
> Issuing exactly the same query as PostgreSQL 8.2.21 and PostgreSQL 9.3.2 will slow the
> response by 6.4 ms on average.
> What could be the cause?
> Measurement method is as follows.
> ・ PostgreSQL 8.2.21 installation
>  ★Measurement
> ・ Export DUMP of PostgreSQL 8.2.21
> ・ PostgreSQL 8.2.21 uninstallation
> ・ PostgreSQL 9.3.2 installation
> ・ Dump import
>  ★Measurement

It is impossible to answer this with certainty without
EXPLAIN (ANALYZE, BUFFERS) output, but my first guess is that
the statistics on the 9.3 installation are not up to date.

ANALYZE all involved tables, then try again and see if the
performance degradation has vanished.

If not, start studying the execution plans.

Are the parameters in postgresql.conf set the same?

Yours,
Laurenz Albe

-- 
Sent via pgsql-performance mailing list ([email protected])
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance


^ permalink  raw  reply  [nested|flat] 2+ messages in thread

end of thread, other threads:[~2017-07-19 06:46 UTC | newest]

Thread overview: 2+ messages (download: mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2017-07-19 01:54 Performance degradation from PostgreSQL 8.2.21 to PostgreSQL 9.3.2 fx TATEISHI KOJI <[email protected]>
2017-07-19 06:46 ` Albe Laurenz <[email protected]>

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox