Re: [PERFORM] Slow query in JDBC - Mailing list pgsql-performance

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@worldline.com> wrote:

https://www.postgresql.org/docs/current/static/auto-explain.html


-----Message d'origine-----
De : pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] De la part de Julien Rouhaud
Envoyé : jeudi 28 septembre 2017 11:21
À : Subramaniam C
Cc : pgsql-performance@postgresql.org
Objet : Re: [PERFORM] Slow query in JDBC

On Thu, Sep 28, 2017 at 10:58 AM, Subramaniam C <subramaniam31784@gmail.com> 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).

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