pgsql: Support foreign keys that reference partitioned tables

Support foreign keys that reference partitioned tables

Previously, while primary keys could be made on partitioned tables, it
was not possible to define foreign keys that reference those primary
keys.  Now it is possible to do that.

Author: Álvaro Herrera
Reviewed-by: Amit Langote, Jesper Pedersen
Discussion: https://postgr.es/m/20181102234158.735b3fevta63msbj@alvherre.pgsql

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/f56f8f8da6afd8523b4d5284e02a20ed2b33ef8d

Modified Files
--------------
doc/src/sgml/ref/create_table.sgml               |    7 +-
src/backend/commands/tablecmds.c                 | 1342 ++++++++++++++++------
src/backend/utils/adt/ri_triggers.c              |  263 ++++-
src/backend/utils/adt/ruleutils.c                |   18 +
src/bin/psql/describe.c                          |    7 +-
src/include/commands/tablecmds.h                 |    4 -
src/include/commands/trigger.h                   |    2 +
src/include/utils/ruleutils.h                    |    1 +
src/test/isolation/expected/fk-partitioned-1.out |  133 +++
src/test/isolation/expected/fk-partitioned-2.out |   70 ++
src/test/isolation/isolation_schedule            |    2 +
src/test/isolation/specs/fk-partitioned-1.spec   |   45 +
src/test/isolation/specs/fk-partitioned-2.spec   |   29 +
src/test/regress/expected/foreign_key.out        |  334 +++++-
src/test/regress/sql/foreign_key.sql             |  213 +++-
15 files changed, 2039 insertions(+), 431 deletions(-)