Re: pgsql-performance issue

On 2016-08-20 12:05, Pavel Stehule wrote:

2016-08-20 13:59 GMT+02:00 <debasis.moharana@ipathsolutions.co.in>:

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:

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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]
 [3]

  https://explain.depesz.com/ [4] [4] [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
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  [4] https://explain.depesz.com/ [4] [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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 [3] https://www.postgresql.org/docs/current/static/sql-explain.html
[3]
 [4] https://explain.depesz.com/ [4]

 Hi,

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

The real time you can see in EXPLAIN ANALYZE ... output. The some
strange time what you can see in PgAdmin can be based on

a) PgAdmin issue - pgAdmin is relativly slow client due slow
formatting - the time of processing in your application can be pretty
better, try to check another client

b) there can be some network issues - the problem is in passing data
from server to client

but probably variant is @a - pgAdmin is not good for benchmarking -
use "psql" console instead.

Pavel

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

Regards,
Debasis Moharana

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[2] http://www.postgresql.org/mailpref/pgsql-performance
[3] https://www.postgresql.org/docs/current/static/sql-explain.html
[4] https://explain.depesz.com/

Hi,

Actually i am fresher on this.So want to connect my application with postgresql instead of MSSQL.

If we are using psql console for executing the query then it will faster according to you.
But what is the other option to use instead of pgadmin.

Can you give me some link for reference.

Regards,
Debasis Moharana