Refactor to reduce code duplication for function property checking.
As noted by Andres Freund, we'd accumulated quite a few similar functions
in clauses.c that examine all functions in an expression tree to see if
they satisfy some boolean test. Reduce the duplication by inventing a
function check_functions_in_node() that applies a simple callback function
to each SQL function OID appearing in a given expression node. This also
fixes some arguable oversights; for example, contain_mutable_functions()
did not check aggregate or window functions for mutability. I doubt that
that represents a live bug at the moment, because we don't really consider
mutability for aggregates; but it might someday be one.
I chose to put check_functions_in_node() in nodeFuncs.c because it seemed
like other modules might wish to use it in future. That in turn forced
moving set_opfuncid() et al into nodeFuncs.c, as the alternative was for
nodeFuncs.c to depend on optimizer/setrefs.c which didn't seem very clean.
In passing, teach contain_leaked_vars_walker() about a few more expression
node types it can safely look through, and improve the rather messy and
undercommented code in has_parallel_hazard_walker().
Discussion: <20160527185853.ziol2os2zskahl7v@alap3.anarazel.de>
Branch
------
master
Details
-------
http://git.postgresql.org/pg/commitdiff/2f153ddfdd318b211590dd5585f65f357d85c2de
Modified Files
--------------
src/backend/nodes/nodeFuncs.c | 178 +++++++++
src/backend/optimizer/plan/setrefs.c | 63 ----
src/backend/optimizer/util/clauses.c | 688 +++++++++-------------------------
src/backend/optimizer/util/predtest.c | 2 +-
src/backend/utils/cache/relcache.c | 2 +-
src/include/nodes/nodeFuncs.h | 10 +
src/include/optimizer/planmain.h | 3 -
7 files changed, 371 insertions(+), 575 deletions(-)
