pgsql: Clean up the mess around EXPLAIN and materialized views.

Clean up the mess around EXPLAIN and materialized views.

Revert the matview-related changes in explain.c's API, as per recent
complaint from Robert Haas. The reason for these appears to have been
principally some ill-considered choices around having intorel_startup do
what ought to be parse-time checking, plus a poor arrangement for passing
it the view parsetree it needs to store into pg_rewrite when creating a
materialized view. Do the latter by having parse analysis stick a copy
into the IntoClause, instead of doing it at runtime. (On the whole,
I seriously question the choice to represent CREATE MATERIALIZED VIEW as a
variant of SELECT INTO/CREATE TABLE AS, because that means injecting even
more complexity into what was already a horrid legacy kluge. However,
I didn't go so far as to rethink that choice ... yet.)

I also moved several error checks into matview parse analysis, and
made the check for external Params in a matview more accurate.

In passing, clean things up a bit more around interpretOidsOption(),
and fix things so that we can use that to force no-oids for views,
sequences, etc, thereby eliminating the need to cons up "oids = false"
options when creating them.

catversion bump due to change in IntoClause. (I wonder though if we
really need readfuncs/outfuncs support for IntoClause anymore.)

Branch
------
master

Details
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http://git.postgresql.org/pg/commitdiff/0b337904213337db5026ef0a756a447588023935

Modified Files
--------------
src/backend/commands/createas.c | 142 +++++++++++------------------------
src/backend/commands/explain.c | 37 +++++----
src/backend/commands/prepare.c | 2 +-
src/backend/commands/sequence.c | 2 +-
src/backend/commands/tablecmds.c | 54 +-------------
src/backend/commands/typecmds.c | 2 +-
src/backend/commands/view.c | 1 -
src/backend/nodes/copyfuncs.c | 2 +-
src/backend/nodes/equalfuncs.c | 2 +-
src/backend/nodes/nodeFuncs.c | 3 +
src/backend/nodes/outfuncs.c | 2 +-
src/backend/nodes/readfuncs.c | 2 +-
src/backend/parser/analyze.c | 62 +++++++++++-----
src/backend/parser/gram.y | 13 +---
src/backend/parser/parse_clause.c | 18 ++--
src/backend/parser/parse_param.c | 36 +++++++++
src/backend/parser/parse_relation.c | 49 ++++++++++++
src/backend/parser/parse_utilcmd.c | 4 +-
src/include/catalog/catversion.h | 2 +-
src/include/commands/createas.h | 4 -
src/include/commands/explain.h | 5 +-
src/include/commands/tablecmds.h | 2 -
src/include/nodes/primnodes.h | 6 +-
src/include/parser/parse_clause.h | 2 +-
src/include/parser/parse_param.h | 1 +
src/include/parser/parse_relation.h | 1 +
26 files changed, 230 insertions(+), 226 deletions(-)