On Tue, 23 Dec 2008 12:25:48 -0500 "Kynn Jones" <kyn...@gmail.com> wrote: > Hi everyone! > I have a very large 2-column table (about 500M records) from which I want to > remove duplicate records. > > I have tried many approaches, but they all take forever. > > The table's definition consists of two short TEXT columns. It is a > temporary table generated from a query: > > CREATE TEMP TABLE huge_table AS SELECT x, y FROM ... ; > > Initially I tried > > CREATE TEMP TABLE huge_table AS SELECT DISTINCT x, y FROM ... ; > > but after waiting for nearly an hour I aborted the query, and repeated it
Do you have an index on x and y? Also, does this work better? CREATE TEMP TABLE huge_table AS SELECT x, y FROM ... GROUP BY x, y; What does ANALYZE EXPLAIN have to say? -- D'Arcy J.M. Cain <da...@druid.net> | Democracy is three wolves http://www.druid.net/darcy/ | and a sheep voting on +1 416 425 1212 (DoD#0082) (eNTP) | what's for dinner. -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
