It's Postgres 9.1.24 on RHEL 6.5 On Tue, Sep 5, 2017 at 8:24 PM, Soni M <diptat...@gmail.com> wrote:
> Consider these 2 index scan produced by a query > > -> Index Scan using response_log_by_activity on public.response_log rl2 > (cost=0.00..51.53 rows=21 width=8) (actual time=9.017..9.056 rows=0 > loops=34098) > Output: rl2.activity_id, rl2.feed_id > Index Cond: (rl2.activity_id = > rl.activity_id) > Filter: rl2.success > Buffers: shared hit=3357159 > read=153313 > -> Index Scan using activity_pkey on > public.activity a (cost=0.00..51.10 rows=1 width=12) (actual > time=0.126..0.127 rows=1 loops=34088) > Output: a.status_id, a.activity_id, > a.visit_id > Index Cond: (a.activity_id = > rl.activity_id) > Buffers: shared hit=137925 read=32728 > > > And it's size > > conscopy=# select pg_size_pretty(pg_relation_size('response_log_by_ > activity'::regclass)); > pg_size_pretty > ---------------- > 7345 MB > (1 row) > > conscopy=# select pg_size_pretty(pg_relation_size('activity_pkey':: > regclass)); > pg_size_pretty > ---------------- > 8110 MB > (1 row) > > Index scan on response_log_by_activity is far slower. The table has just > been repacked, and index rebuilt, but still slow. > > Is there any other way to make it faster ? > > Why Buffers: shared hit=3,357,159 read=153,313 on response_log_by_activity > is much bigger than Buffers: shared hit=137925 read=32728 on activity_pkey > while activity_pkey size is bigger ? > > -- > Regards, > > Soni Maula Harriz > -- Regards, Soni Maula Harriz