Slow query-plan generation (fast query) PG 9.2 - Mailing list pgsql-performance

From jesper@krogh.cc
Subject Slow query-plan generation (fast query) PG 9.2
Date
Msg-id e9ed24069c06d8b504fbef3e28df52d7.squirrel@shrek.krogh.cc
Whole thread Raw
Responses Re: Slow query-plan generation (fast query) PG 9.2
List pgsql-performance
Hi.

I have a strange situation where generating the query plan takes 6s+ and
executing it takes very little time.

2013-09-03 09:19:38.726 db=# explain select table.id  from db.table left
join db.tablepro on db.id = tablepro.table_id where table.fts @@
to_tsquery('english','q12345') ;
                                                    QUERY PLAN
-------------------------------------------------------------------------------------------------------------------
 Nested Loop Left Join  (cost=43.71..12711.39 rows=2930 width=4)
   ->  Bitmap Heap Scan on sequence  (cost=43.71..4449.10 rows=2930 width=4)
         Recheck Cond: (fts @@ '''q12345'''::tsquery)
         ->  Bitmap Index Scan on table_gin_idx  (cost=0.00..42.98
rows=2930 width=0)
               Index Cond: (fts @@ '''q12345'''::tsquery)
   ->  Index Only Scan using tablepro_seqid_idx on tablepro
(cost=0.00..2.81 rows=1 width=4)
         Index Cond: (tablepro_id = table.id)
(7 rows)

Time: 10458.404 ms


The query gives 4 rows out of 50.000.000, so the query-plan is actually
correct and as expected.

Any suggestions?

Jesper




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