Re: pgsql-performance issue

[debasis.moharana@xxxxxxxxxxxxxxxxxxxx]

On 2016-08-20 11:42, Pavel Stehule wrote:
> 2016-08-20 13:31 GMT+02:00 <debasis.moharana@xxxxxxxxxxxxxxxxxxxx>:
>
> > On 2016-08-20 08:58, Pavel Stehule wrote:
> > 2016-08-20 10:27 GMT+02:00 <debasis.moharana@xxxxxxxxxxxxxxxxxxxx>:
> >
> > On 2016-08-20 08:21, pgsql-performance-owner@xxxxxxxxxxxxxx wrote:
> >
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> <https://lists.postgresql.org/mj/mj_wwwusr/domain=postgresql.org/debasis.moharana%40ipathsolutions.co.in
> [2]
>
> > > [1]>
> > Dear Sir/Mam,
> >
> > I have a PostgreSQL 9.5 instance running on Windows 8 machine with
> > 4GB of RAM.This server is mainly used for inserting/updating large
> > amounts of data via copy/insert/update commands, and seldom for
> > running select queries.
> >
> > Here are the relevant configuration parameters I changed:
> >
> > max_connections = 100
> > shared_buffers = 512MB
> > effective_cache_size = 3GB
> > work_mem = 12233kB
> > maintenance_work_mem = 256MB
> > min_wal_size = 1GB max_wal_size = 2GB
> > checkpoint_completion_target = 0.7
> > wal_buffers = 16MB
> > default_statistics_target = 100
> >
> > After setting in postgresql.conf. I run the select query to fetch
> > large amount of record of 29000 in postgresql but it takes 10.3
> > seconds but the same query takes 2 seconds for execution in MSSQL.
> >
> > So my query is how to improve the perfermance in postgresql.
>
>  hi
>
>  please, send execution plan of slow query
>
>  https://www.postgresql.org/docs/current/static/sql-explain.html [3]
> [3]
>  https://explain.depesz.com/ [4] [4]
>
>  p.s. Did you do VACUUM and ANALYZE on database?
>
>  Regards
>
>  Pavel
>
> > Regards,
> > Debasis Moharana
> > .NET Software Developer
> >
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>  [2] http://www.postgresql.org/mailpref/pgsql-performance [1]
>  [3] https://www.postgresql.org/docs/current/static/sql-explain.html
> [3]
>  [4] https://explain.depesz.com/ [4]
>
>  Hi,
>
>  Please check the execution plan details
>
>  Execution Query is = EXPLAIN (ANALYZE, BUFFERS) select * from
> tblPurchaseOrderstock cross join tblPurchaseOrderInfo;
>
>  "Nested Loop  (cost=0.00..507.51 rows=39593 width=224) (actual
> time=0.032..13.026 rows=39593 loops=1)"
>  "  Buffers: shared read=8"
>  "  I/O Timings: read=0.058"
>  "  ->  Seq Scan on tblpurchaseorderstock  (cost=0.00..7.89 rows=289
> width=95) (actual time=0.014..0.082 rows=289 loops=1)"
>  "        Buffers: shared read=5"
>  "        I/O Timings: read=0.040"
>  "  ->  Materialize  (cost=0.00..5.05 rows=137 width=129) (actual
> time=0.000..0.006 rows=137 loops=289)"
>  "        Buffers: shared read=3"
>  "        I/O Timings: read=0.019"
>  "        ->  Seq Scan on tblpurchaseorderinfo  (cost=0.00..4.37
> rows=137 width=129) (actual time=0.011..0.035 rows=137 loops=1)"
>  "              Buffers: shared read=3"
>  "              I/O Timings: read=0.019"
>  "Planning time: 56.052 ms"
>  "Execution time: 14.038 ms"
>
> It is same query? It needs only 14ms
>
> Regards
>
> Pavel
>
> > Regards,
> > Debasis Moharana
>
>
>
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> https://lists.postgresql.org/mj/mj_wwwusr/domain=postgresql.org/debasis.moharana%40ipathsolutions.co.in
> [3] https://www.postgresql.org/docs/current/static/sql-explain.html
> [4] https://explain.depesz.com/



Hi,

Yes you right.But it will take more time(10.3 sec.) Plase check the 
snap.


Can you please tell me what we need to setup so that it will take the 
actual time.

Regards,
Debasis Moharana

Attachment: queryplan.png
Description: PNG image

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