Re: Slow query in JDBC

Subramaniam C <subramaniam31784@xxxxxxxxx> · Thu, 28 Sep 2017 15:29:08 +0530

First output show the output when the query is executed from sql command line. The second output show when it is executed from the application. AS per the output it is clear that the when the query is executed through JDBC its not using the index (health_index) instead its doing sequence scan. Please let us know how this issue can be resolved from JDBC?

1.)

Limit  (cost=510711.53..510711.58 rows=20 width=72)
	  ->  Sort  (cost=510711.53..511961.53 rows=500000 width=72)
	        Sort Key: health_timeseries_table.health
	        ->  WindowAgg  (cost=0.98..497406.71 rows=500000 width=72)
	              ->  Merge Left Join  (cost=0.98..491156.71 rows=500000 width=64)
	                    Merge Cond: (object_table.uuid = health_timeseries_table.mobid)
	                    ->  Unique  (cost=0.42..57977.00 rows=500000 width=64)
	                          ->  Index Scan Backward using object_table_pkey on object_table  (cost=0.42..56727.00 rows=500000 width=64)
	                                Index Cond: (("timestamp" >= 0) AND ("timestamp" <= '1505990086834'::bigint))
	                                Filter: (tenantid = 'perspica'::text)
	                    ->  Materialize  (cost=0.56..426235.64 rows=55526 width=16)
	                          ->  Unique  (cost=0.56..425541.56 rows=55526 width=24)
	                                ->  Index Only Scan using health_index on health_timeseries_table  (cost=0.56..421644.56 rows=1558800 width=24)
	                                      Index Cond: (("timestamp" >= '1505989186834'::bigint) AND ("timestamp" <= '1505990086834'::bigint))
LOG:  duration: 1971.697 ms

2.)

Limit  (cost=457629.21..457629.26 rows=20 width=72)
	  ->  Sort  (cost=457629.21..458879.21 rows=500000 width=72)
	        Sort Key: health_timeseries_table.health
	        ->  WindowAgg  (cost=367431.49..444324.39 rows=500000 width=72)
	              ->  Merge Left Join  (cost=367431.49..438074.39 rows=500000 width=64)
	                    Merge Cond: (object_table.uuid = health_timeseries_table.mobid)
	                    ->  Unique  (cost=0.42..57977.00 rows=500000 width=64)
	                          ->  Index Scan Backward using object_table_pkey on object_table  (cost=0.42..56727.00 rows=500000 width=64)
	                                Index Cond: (("timestamp" >= '0'::bigint) AND ("timestamp" <= '1505990400000'::bigint))
	                                Filter: (tenantid = 'perspica'::text)
	                    ->  Materialize  (cost=367431.07..373153.32 rows=55526 width=16)
	                          ->  Unique  (cost=367431.07..372459.24 rows=55526 width=24)
	                                ->  Sort  (cost=367431.07..369945.16 rows=1005634 width=24)
	                                      Sort Key: health_timeseries_table.mobid DESC, health_timeseries_table."timestamp" DESC, health_timeseries_table.health
	                                      ->  Seq Scan on health_timeseries_table  (cost=0.00..267171.00 rows=1005634 width=24)

	                                            Filter: (("timestamp" >= '1505989500000'::bigint) AND ("timestamp" <= '1505990400000'::bigint))

On Thu, Sep 28, 2017 at 2:56 PM, Pavy Philippe <Philippe.Pavy@xxxxxxxxxxxxx> wrote:
https://www.postgresql.org/docs/current/static/auto-explain.html

-----Message d'origine-----

De : pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] De la part de Julien Rouhaud

Envoyé : jeudi 28 septembre 2017 11:21

À : Subramaniam C

Cc : pgsql-performance@postgresql.org

Objet : Re:  Slow query in JDBC

On Thu, Sep 28, 2017 at 10:58 AM, Subramaniam C <subramaniam31784@xxxxxxxxx> wrote:

> I configured cursor_tuple_fraction to 1 but still I am facing the same

> issue.

Can you show explain (analyze, buffers) of the query when run from psql and run from application (you can use auto_explain for that if needed, see https://www.postgresql.org/docs/current/static/auto-explain.html).

--

Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)

To make changes to your subscription:

http://www.postgresql.org/mailpref/pgsql-performance

!!!*************************************************************************************

"Ce message et les pièces jointes sont confidentiels et réservés à l'usage exclusif de ses destinataires. Il peut également être protégé par le secret professionnel. Si vous recevez ce message par erreur, merci d'en avertir immédiatement l'expéditeur et de le détruire. L'intégrité du message ne pouvant être assurée sur Internet, la responsabilité de Worldline ne pourra être recherchée quant au contenu de ce message. Bien que les meilleurs efforts soient faits pour maintenir cette transmission exempte de tout virus, l'expéditeur ne donne aucune garantie à cet égard et sa responsabilité ne saurait être recherchée pour tout dommage résultant d'un virus transmis.

This e-mail and the documents attached are confidential and intended solely for the addressee; it may also be privileged. If you receive this e-mail in error, please notify the sender immediately and destroy it. As its integrity cannot be secured on the Internet, the Worldline liability cannot be triggered for the message content. Although the sender endeavours to maintain a computer virus-free network, the sender does not warrant that this transmission is virus-free and will not be liable for any damages resulting from any virus transmitted.!!!"