On Mon, Jan 12, 2009 at 4:16 PM, Reg Me Please <regmeple...@gmail.com> wrote: > On Monday 12 January 2009 21:38:02 Bruno Lavoie wrote: >> Hello, >> >> I have a column with a small number of distinct values, indexing this >> one with a standard BTree is useless. How do I can index this column >> efficiently? I searched and it seems that pg doesn't support the >> creation of persistent bitmap indexes... Is that feature planned in next >> releases of pg? >> >> Thanks >> Bruno Lavoie > > I would try partial indexes, as many as the distinct values. > I'm not sure this would help, though. >
you should create partial indexes only on those values that are a lower fraction on the table ie: if you have value "fraction of the table that has this value" 1 5% 2 3% 3 20% 4 25% 5 47% then only partial indexes on values 1 and 2 are of some value -- Atentamente, Jaime Casanova Soporte y capacitación de PostgreSQL AsesorÃa y desarrollo de sistemas Guayaquil - Ecuador Cel. +59387171157 -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
