pgsql-server/src/backend/optimizer README prep ...

CVSROOT:    /cvsroot
Module name:    pgsql-server
Changes by:    tgl@svr1.postgresql.org    03/12/30 17:49:19

Modified files:
    src/backend/optimizer: README
    src/backend/optimizer/prep: prepqual.c

Log message:
    Instead of trying to force WHERE clauses into CNF or DNF normal form,
    just look for common clauses that can be pulled out of ORs.  Per recent
    discussion, extracting common clauses seems to be the only really useful
    effect of normalization, and if we do it explicitly then we can avoid
    cluttering the qual with partially-redundant duplicated expressions, which
    was an unpleasant side-effect of the old approach.