On 1/10/16, Saulo Merlo <smerlo50@xxxxxxxxxxx> wrote: > Hi Vitaly, > > Yep... gorfs.nodes is a view. > And the schema is: gorfs.inode_segments > So... CREATE INDEX index_name ON gorfs.inode_segments(st_ctime) > Is that correct? It would be "st_ctime"? If "inodes" is an alias for "gorfs.inode_segments" in your view, yes, the above DDL is OK. According to EXPLAIN's "Filter" row the column involving in comparison is st_ctime. Hint: you can create the index without blocking table using "CREATE INDEX CONCURRENTLY": http://www.postgresql.org/docs/9.2/static/sql-createindex.html > I've rewriten the query as well. Thank you for that! > > Thank you > Lucas >> Date: Sun, 10 Jan 2016 21:23:01 -0800 >> Subject: Re: Slow Query - PostgreSQL 9.2 >> From: vitaly.burovoy@xxxxxxxxx >> To: smerlo50@xxxxxxxxxxx >> CC: pgsql-general@xxxxxxxxxxxxxx >> >> On 1/10/16, Vitaly Burovoy <vitaly.burovoy@xxxxxxxxx> wrote: >> > On 1/10/16, Saulo Merlo <smerlo50@xxxxxxxxxxx> wrote: >> >> I've got a slow query.. I'd like to make it faster.. Make add an >> >> index? >> >> Query: >> >> SELECT >> >> <<overquoting>> >> >> FROM gorfs.nodes AS f >> >> <<overquoting>> >> >> WHERE f.file_data IS NOT NULL >> >> AND ((transaction_timestamp() AT TIME ZONE 'UTC') > (f.last_changed >> >> + >> >> '24 >> >> months' :: INTERVAL)) LIMIT 100; >> > >> >> <<overquoting>> >> >> "Total runtime: 94989.208 ms"What could I do to make it faster? Thank >> >> you. >> > >> > At least you can add an index: >> > CREATE INDEX ON gorfs.nodes(last_changed) >> > >> > and rewrite part of WHERE clause to: >> > (f.last_changed < (transaction_timestamp() AT TIME ZONE 'UTC' - '24 >> > months'::INTERVAL)) >> > >> > It allows to decrease the slowest part of your query (sequence >> > scanning of a table, all 13.5M rows): >> >> -> Seq Scan on "inodes" "t" (cost=0.00..1411147.24 rows=13416537 >> >> width=29) (actual time=94987.224..94987.224 rows=0 loops=1) >> >> Filter: ("timezone"('UTC'::"text", "transaction_timestamp"()) > >> >> (("st_ctime")::timestamp without time zone + '2 years'::interval)) >> > >> > compare that time to the one in the topmost row of EXPLAIN: >> >> Limit (cost=1556.99..1336437.30 rows=100 width=186) (actual >> >> time=94987.261..94987.261 rows=0 loops=1) >> >> Hmm. It seems that gorfs.nodes is a view. >> So creating index should be something like (I have no idea that schema >> name for it): >> CREATE INDEX ON _schema_name_.inodes(st_ctime) -- Best regards, Vitaly Burovoy -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
