""Ahmad Fajar"" <[EMAIL PROTECTED]> wrote > Hi Qingqing, > > I don't know whether the statistic got is bad or good, this is the > statistic:
Please do it in this way: 1. Start postmaster with "stats_start_collector=true" and "stats_block_level=true". 2. Use psql connect it, do something like this: test=# select pg_stat_reset(); pg_stat_reset --------------- t (1 row) test=# select * from pg_statio_user_indexes ; relid | indexrelid | schemaname | relname | indexrelname | idx_blks_read | idx_ blks_hit -------+------------+------------+---------+--------------+---------------+----- --------- 16385 | 16390 | public | test | test_idx | 0 | 0 (1 row) test=# select count(*) from test where a <= 1234; count ------- 7243 (1 row) test=# select * from pg_statio_user_indexes ; relid | indexrelid | schemaname | relname | indexrelname | idx_blks_read | idx_ blks_hit -------+------------+------------+---------+--------------+---------------+----- --------- 16385 | 16390 | public | test | test_idx | 55 | 0 (1 row) This gives us that to get "select count(*) from test where a <= 1234", I have to read 55 index blocks (no index block hit since I just restart postmaster so the bufferpool is empty). Regards, Qingqing ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster