pgsql: Implement an API to let foreign-data wrappers actually be functi

Implement an API to let foreign-data wrappers actually be functional.

This commit provides the core code and documentation needed. A contrib
module test case will follow shortly.

Shigeru Hanada, Jan Urbanski, Heikki Linnakangas

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/bb742407947ad1cbf19355d24282380d576e7654

Modified Files
--------------
doc/src/sgml/ddl.sgml | 47 +++++
doc/src/sgml/fdwhandler.sgml | 212 +++++++++++++++++++++
doc/src/sgml/filelist.sgml | 1 +
doc/src/sgml/postgres.sgml | 1 +
doc/src/sgml/ref/create_foreign_data_wrapper.sgml | 13 +-
doc/src/sgml/ref/create_foreign_table.sgml | 4 +-
src/backend/commands/explain.c | 51 ++++--
src/backend/executor/Makefile | 2 +-
src/backend/executor/execAmi.c | 5 +
src/backend/executor/execMain.c | 7 +
src/backend/executor/execProcnode.c | 14 ++
src/backend/executor/nodeForeignscan.c | 209 ++++++++++++++++++++
src/backend/foreign/foreign.c | 159 ++++++++++++++--
src/backend/nodes/copyfuncs.c | 44 +++++
src/backend/nodes/outfuncs.c | 41 ++++
src/backend/optimizer/README | 1 +
src/backend/optimizer/path/allpaths.c | 36 ++++-
src/backend/optimizer/path/costsize.c | 28 +++
src/backend/optimizer/plan/createplan.c | 86 +++++++++
src/backend/optimizer/plan/planner.c | 3 +-
src/backend/optimizer/plan/setrefs.c | 12 ++
src/backend/optimizer/plan/subselect.c | 4 +
src/backend/optimizer/util/pathnode.c | 36 ++++
src/backend/optimizer/util/plancat.c | 11 +-
src/backend/parser/analyze.c | 18 ++-
src/backend/rewrite/rewriteHandler.c | 8 +-
src/backend/utils/fmgr/fmgr.c | 20 ++
src/include/commands/explain.h | 11 +
src/include/executor/nodeForeignscan.h | 24 +++
src/include/fmgr.h | 1 +
src/include/foreign/fdwapi.h | 98 ++++++++++
src/include/foreign/foreign.h | 8 +
src/include/nodes/execnodes.h | 14 ++
src/include/nodes/nodes.h | 7 +-
src/include/nodes/plannodes.h | 12 ++
src/include/nodes/relation.h | 10 +
src/include/optimizer/cost.h | 1 +
src/include/optimizer/pathnode.h | 1 +
src/test/regress/expected/foreign_data.out | 4 +-
39 files changed, 1202 insertions(+), 62 deletions(-)