On Wed, Jan 25, 2012 at 02:07:40PM -0800, Adrian Klaver wrote: > Finally dawned on me. When you use 'at time zone' on a timestamp > with tz it strips the tz which then allows the value to be indexed > because: > > -[ RECORD 5 ]-------+------------------------------------------------------------------------- > Schema | pg_catalog > Name | date_part > Result data type | double precision > Argument data types | text, timestamp without time zone > Type | normal > Volatility | immutable > Owner | postgres > Language | internal > Source code | timestamp_part > Description | extract field from timestamp yes, but it is not correct - the value is actually stable, and not immutable. Best regards, depesz -- The best thing about modern society is how easy it is to avoid contact with it. http://depesz.com/ -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general