Re: Join Bad Performance on different data types

[Adarsh Sharma <eddy.adarsh@xxxxxxxxx>]

On Tue, Mar 4, 2014 at 1:13 PM, Sameer Kumar <sameer.kumar@xxxxxxxxxx> wrote:

On Tue, Mar 4, 2014 at 2:57 PM, Adarsh Sharma <eddy.adarsh@xxxxxxxxx> wrote:

I tried creating simple and gin indexes on the column(t_ids) but still not helping. Anyone has any idea or faced this before. Postgresql version is 9.2.

have you done a vacuum analyze or analyze after this step?

You might have to disable sequential scans

set enable_seqscan=off;

And then fire the query.

Thanks Sameer. yes i already did vacuum analyze but i tried enable_seqscan=off; this time and explain analyze finished in 34 seconds.


PLAN                                                                                     
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 HashAggregate  (cost=10651634346.70..10651780073.12 rows=4163612 width=64) (actual time=34375.675..34764.705 rows=751392 loops=1)
   ->  Nested Loop  (cost=10000000000.03..10646590270.49 rows=336271747 width=64) (actual time=0.217..24988.534 rows=6541944 loops=1)
         ->  Nested Loop  (cost=10000000000.02..10012318364.23 rows=33628639 width=116) (actual time=0.177..3427.380 rows=1431 loops=1)
               ->  Nested Loop  (cost=10000000000.01..10001045237.36 rows=3368723 width=38) (actual time=0.138..3373.767 rows=1431 loops=1)
                     ->  Nested Loop  (cost=10000000000.00..10000097742.23 rows=340181 width=38) (actual time=0.047..2151.183 rows=418145 loops=1)
                           Join Filter: (td.entity_type_id = gtt.id)
                           Rows Removed by Join Filter: 1269335
                           ->  Seq Scan on graph5 td  (cost=10000000000.00..10000077008.13 rows=345413 width=33) (actual time=0.020..1231.823 rows=421870 loops=1)
                           ->  Materialize  (cost=0.00..9.33 rows=4 width=13) (actual time=0.000..0.001 rows=4 loops=421870)
                                 ->  Index Scan using geo_type_pkey on graph6 gtt  (cost=0.00..9.31 rows=4 width=13) (actual time=0.009..0.012 rows=4 loops=1)
                     ->  Index Scan using graph2_pkey on graph2 gcr  (cost=0.01..2.69 rows=10 width=33) (actual time=0.002..0.002 rows=0 loops=418145)
                           Index Cond: (id = ANY (td.graph3_id))
               ->  Index Scan using graph3_pkey on graph3 gtd  (cost=0.01..3.25 rows=10 width=115) (actual time=0.035..0.036 rows=1 loops=1431)
                     Index Cond: (id = ANY (gcr.t_ids))
         ->  Index Scan using graph1_pkey on graph1 glt  (cost=0.01..18.51 rows=10 width=55) (actual time=0.085..9.082 rows=4572 loops=1431)
               Index Cond: (id = ANY (gtd.lat_long_id_list))
 Total runtime: 34810.040 ms

Is dere any way i can rewrite the query so that i need not to set seqscan-off,  because i dont want to embed one more line in application code and also dont want to change global setting in postgresql.conf to disable seqscan.

Thanks

 

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