pgsql: Handle heap rewrites even better in logical decoding

Handle heap rewrites even better in logical decoding

Logical decoding should not publish anything about tables created as
part of a heap rewrite during DDL.  Those tables don't exist externally,
so consumers of logical decoding cannot do anything sensible with that
information.  In ab28feae2bd3d4629bd73ae3548e671c57d785f0, we worked
around this for built-in logical replication, but that was hack.

This is a more proper fix: We mark such transient heaps using the new
field pg_class.relwrite, linking to the original relation OID.  By
default, we ignore them in logical decoding before they get to the
output plugin.  Optionally, a plugin can register their interest in
getting such changes, if they handle DDL specially, in which case the
new field will help them get information about the actual table.

Reviewed-by: Craig Ringer <craig@2ndquadrant.com>

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/325f2ec5557fd1c9156c910102522e04cb42d99c

Modified Files
--------------
.../test_decoding/expected/concurrent_ddl_dml.out  | 82 ++++++++--------------
contrib/test_decoding/expected/ddl.out             | 20 +++---
.../test_decoding/specs/concurrent_ddl_dml.spec    |  2 +-
contrib/test_decoding/sql/ddl.sql                  |  5 +-
contrib/test_decoding/test_decoding.c              | 14 ++++
doc/src/sgml/catalogs.sgml                         | 12 ++++
doc/src/sgml/logicaldecoding.sgml                  |  5 ++
src/backend/bootstrap/bootparse.y                  |  1 +
src/backend/catalog/heap.c                         |  4 ++
src/backend/catalog/toasting.c                     |  1 +
src/backend/commands/cluster.c                     |  1 +
src/backend/commands/tablecmds.c                   |  1 +
src/backend/replication/logical/logical.c          |  4 ++
src/backend/replication/logical/reorderbuffer.c    |  7 ++
src/backend/replication/pgoutput/pgoutput.c        | 26 -------
src/include/catalog/catversion.h                   |  2 +-
src/include/catalog/heap.h                         |  1 +
src/include/catalog/pg_class.h                     | 22 +++---
src/include/replication/output_plugin.h            |  1 +
src/include/replication/reorderbuffer.h            |  5 ++
20 files changed, 113 insertions(+), 103 deletions(-)