Re: pgsql-performance issue

2016-08-20 13:31 GMT+02:00 <debasis(dot)moharana(at)ipathsolutions(dot)co(dot)in>:

> On 2016-08-20 08:58, Pavel Stehule wrote:
>
>> 2016-08-20 10:27 GMT+02:00 <debasis(dot)moharana(at)ipathsolutions(dot)co(dot)in>:
>>
>> On 2016-08-20 08:21, pgsql-performance-owner(at)postgresql(dot)org wrote:
>>>
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>>> <https://lists.postgresql.org/mj/mj_wwwusr/domain=postgresql
>> .org/debasis.moharana%40ipathsolutions.co.in
>>
>>> [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]
>> https://explain.depesz.com/ [4]
>>
>> p.s. Did you do VACUUM and ANALYZE on database?
>>
>> Regards
>>
>> Pavel
>>
>> Regards,
>>> Debasis Moharana
>>> .NET Software Developer
>>>
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>> [3] https://www.postgresql.org/docs/current/static/sql-explain.html
>> [4] https://explain.depesz.com/
>>
>
>
>
> 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
>