In your first post you said that the query is taking much longer than a second, and in your second post you say the performance is horrible, but explain analyze shows the query runs in 219 milliseconds, which doesn't seem too bad to me. I wonder if the slow part for you is returning all the rows to the client? How are you running this query? (JDBC, ODBC, C library?) Do you really need all the rows? Maybe you could use a cursor to page through the rows? Dave > -----Original Message----- > From: pgsql-performance-owner@xxxxxxxxxxxxxx > [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] On Behalf Of s d > Sent: Monday, April 09, 2007 7:46 PM > To: Jan de Visser > Cc: pgsql-performance@xxxxxxxxxxxxxx > Subject: Re: [PERFORM] Beginner Question > > > Hi Jan, > Adding this Index slowed down things by a factor of 4. > > Also, the performance is so horrible (example bellow) that i am > certain i am doing something wrong. > > Does the following explain gives any ideas ? > > Thanks > > =# EXPLAIN ANALYZE select * from word_association where (word1 ='the' > or word2='the') and count > 10; > > QUERY PLAN > -------------------------------------------------------------- > -------------------------------------------------------------- > -------------------- > Bitmap Heap Scan on word_association (cost=250.86..7256.59 rows=4624 > width=22) (actual time=13.461..211.568 rows=6601 loops=1) > Recheck Cond: (((word1)::text = 'the'::text) OR ((word2)::text = > 'the'::text)) > Filter: (count > 10) > -> BitmapOr (cost=250.86..250.86 rows=12243 width=0) (actual > time=9.052..9.052 rows=0 loops=1) > -> Bitmap Index Scan on word_association_index1_1 > (cost=0.00..153.20 rows=7579 width=0) (actual time=5.786..5.786 > rows=7232 loops=1) > Index Cond: ((word1)::text = 'the'::text) > -> Bitmap Index Scan on word_association_index2_1 > (cost=0.00..95.34 rows=4664 width=0) (actual time=3.253..3.253 > rows=4073 loops=1) > Index Cond: ((word2)::text = 'the'::text) > Total runtime: 219.987 ms > (9 rows)
