Note that a VACUUM wouldn't be able to remove the dead rows if there's a long running active query OR any idle transaction in an isolation >= Repeatable Read, tracking transactions in "pg_stat_activity" should help you eliminate/track this activity. Also, the row estimates consider the size of your table, so it isn't necessary that close estimates indicate an ANALYZE operation performed, a better way to track this would be monitoring results from "pg_stat_user_tables", tracking when was did the autovacuum/analyze last performed on this table
Regards, Akash On Mon, Sep 12, 2016 at 4:36 PM, Francisco Olarte <fola...@peoplecall.com> wrote: > Hi: > > On Mon, Sep 12, 2016 at 1:17 AM, Patrick B <patrickbake...@gmail.com> > wrote: > >> schemaname relname n_live_tup n_dead_tup > >> ---------- ------------- ---------- ---------- > >> public parts 191623953 182477402 > ... > > Because of that the table is very slow... > > When I do a select on that table it doesn't use an index, for example: > > \d parts; > >> "index_parts_id" btree (company_id) > >> "index_parts_id_and_country" btree (company_id, country) > > explain select * from parts WHERE company_id = 12; > >> Seq Scan on parts (cost=0.00..6685241.40 rows=190478997 width=223) > >> Filter: (company_id = 12) > > You've already been directed to check table is really getting vacuumed > / analyzed, but I'd like to point that if the count estimates are > nearly correct that plan is good ( it's estimating getting more than > 99% of the table, a seq scan tends to beat index scan easily when > selecting that big part of the table, even accounting for dead tuples > it's more about 50% of the table, and a seq scan is much faster PER > TUPLE then an index scan ( and and index scan would likely touch every > data page for that big fraction, so reading all of them sequentially > and oing a quick filter is easier )). > > Francisco Olarte. > > > -- > Sent via pgsql-general mailing list (pgsql-general@postgresql.org) > To make changes to your subscription: > http://www.postgresql.org/mailpref/pgsql-general >
