pgsql/src/backend/optimizer/prep (prepunion.c) - Mailing list pgsql-committers

  Date: Thursday, December 14, 2000 @ 17:30:44
Author: tgl

Update of /home/projects/pgsql/cvsroot/pgsql/src/backend/optimizer/prep
     from hub.org:/home/projects/pgsql/tmp/cvs-serv78433/src/backend/optimizer/prep

Modified Files:
    prepunion.c

-----------------------------  Log Message  -----------------------------

Planner speedup hacking.  Avoid saving useless pathkeys, so that path
comparison does not consider paths different when they differ only in
uninteresting aspects of sort order.  (We had a special case of this
consideration for indexscans already, but generalize it to apply to
ordered join paths too.)  Be stricter about what is a canonical pathkey
to allow faster pathkey comparison.  Cache canonical pathkeys and
dispersion stats for left and right sides of a RestrictInfo's clause,
to avoid repeated computation.  Total speedup will depend on number of
tables in a query, but I see about 4x speedup of planning phase for
a sample seven-table query.