time zones.
SQL99 spec requires a default of zero (round to seconds) which is set
in gram.y as typmod is set in the parse tree. We *could* change to a
default of either 6 (for internal compatibility with previous versions)
or 2 (for external compatibility with previous versions).
Evaluate entries in pg_proc wrt the iscachable attribute for timestamp and
other date/time types. Try to recognize cases where side effects like the
current time zone setting may have an effect on results to decide whether
something is cachable or not.
3e1beda2cd