On Mon, Oct 31, 2011 at 3:24 PM, Robert Haas <robertmhaas@xxxxxxxxx> wrote: > Sure it does: > > rhaas=# create table baz (a bool, b int, c text, primary key (a, b)); > NOTICE: CREATE TABLE / PRIMARY KEY will create implicit index > "baz_pkey" for table "baz" > CREATE TABLE > rhaas=# insert into baz select true, g, > random()::text||random()::text||random()::text||random()::text from > generate_series(1,400000) g; Ok, that's artificially skewed, since the index has only one value in the first column. But it does prove PG considers the case, and takes into account the number of values it has to iterate over on the first column, which is very very interesting and cool. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
