Re: pgsql-performance issue - Mailing list pgsql-performance

On 2016-08-20 11:42, Pavel Stehule wrote:
> 2016-08-20 13:31 GMT+02:00 <debasis.moharana@ipathsolutions.co.in>:
>
>> On 2016-08-20 08:58, Pavel Stehule wrote:
>> 2016-08-20 10:27 GMT+02:00 <debasis.moharana@ipathsolutions.co.in>:
>>
>> On 2016-08-20 08:21, pgsql-performance-owner@postgresql.org wrote:
>>
>> Welcome to the pgsql-performance mailing list!
>> Your password at PostgreSQL Mailing Lists is
>>
>> x8DiA6
>>
>> To leave this mailing list, send the following command in the
>> body
>> of a message to majordomo@postgresql.org:
>>
>> approve x8DiA6 unsubscribe pgsql-performance
>> debasis.moharana@ipathsolutions.co.in
>>
>> This command will work even if your address changes. For that
>> reason,
>> among others, it is important that you keep a copy of this
>> message.
>>
>> To post a message to the mailing list, send it to
>> pgsql-performance@postgresql.org
>>
>> If you need help or have questions about the mailing list, please
>> contact the people who manage the list by sending a message to
>> pgsql-performance-owner@postgresql.org
>>
>> You can manage your subscription by visiting the following WWW
>> location:
>
> <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
>>
>> --
>> Sent via pgsql-performance mailing list
>> (pgsql-performance@postgresql.org)
>> To make changes to your subscription:
>> http://www.postgresql.org/mailpref/pgsql-performance [1] [2]
>
>  Links:
>  ------
>  [1]
>
> https://lists.postgresql.org/mj/mj_wwwusr/domain=postgresql.org/debasis.moharana%40ipathsolutions.co.in
> [2]
>  [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
>
>
>
> Links:
> ------
> [1] http://www.postgresql.org/mailpref/pgsql-performance
> [2]
> 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