pgsql: Hash support for row types

Hash support for row types

Add hash functions for the record type as well as a hash operator
family and operator class for the record type.  This enables all the
hash functionality for the record type such as hash-based plans for
UNION/INTERSECT/EXCEPT DISTINCT, recursive queries using UNION
DISTINCT, hash joins, and hash partitioning.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/38eccd35-4e2d-6767-1b3c-dada1eac3124%402ndquadrant.com

Branch
------
master

Details
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https://git.postgresql.org/pg/commitdiff/01e658fa74cb7e3292448f6663b549135958003b

Modified Files
--------------
doc/src/sgml/queries.sgml               |   9 --
src/backend/utils/adt/rowtypes.c        | 249 ++++++++++++++++++++++++++++++++
src/backend/utils/cache/lsyscache.c     |   7 +-
src/backend/utils/cache/typcache.c      |  78 +++++++---
src/include/catalog/catversion.h        |   2 +-
src/include/catalog/pg_amop.dat         |   5 +
src/include/catalog/pg_amproc.dat       |   4 +
src/include/catalog/pg_opclass.dat      |   2 +
src/include/catalog/pg_operator.dat     |   2 +-
src/include/catalog/pg_opfamily.dat     |   2 +
src/include/catalog/pg_proc.dat         |   7 +
src/test/regress/expected/hash_func.out |  21 +++
src/test/regress/expected/join.out      |   1 +
src/test/regress/expected/union.out     |  83 ++++++-----
src/test/regress/expected/with.out      |  33 ++++-
src/test/regress/sql/hash_func.sql      |  17 +++
src/test/regress/sql/join.sql           |   1 +
src/test/regress/sql/union.sql          |  12 +-
src/test/regress/sql/with.sql           |   2 +-
19 files changed, 462 insertions(+), 75 deletions(-)