Re: Logical Replication WIP

Hi all,

attaching updated version of the patch. Still very much WIP but it's
slowly getting there.

Changes since last time:
- Mostly rewrote publication handling in pgoutput which brings a)
ability to add FOR ALL TABLES publications, b) performs better (no need
to syscache lookup for every change like before), c) does correct
invalidation of publications on DDL
- added FOR TABLE and FOR ALL TABLES clause to both CREATE PUBLICATION
and ALTER PUBLICATION so that one can create publication directly with
table list, the FOR TABLE in ALTER PUBLICATION behaves like SET
operation (removes existing, adds new ones)
- fixed several issues with initial table synchronization (most of which
have been reported here)
- added pg_stat_subscription monitoring view
- updated docs to reflect all the changes, also removed the stuff that's
only planned from the docs (there is copy of the planned stuff docs in
the neighboring thread so no need to keep it in the patch)
- added documentation improvements suggested by Steve Singer and removed
the capitalization in the main doc
- added pg_dump support
- improved psql support (\drp+ shows list of tables)
- added flags to COMMIT message in the protocol so that we can add 2PC
support in the future
- fixed DROP SUBSCRIPTION issues and added tests for it

I decided to not deal with ACLs so far, assuming superuser/replication
role for now. We can always make it less restrictive later by adding the
grantable privileges.

FDW support is still TODO. I think TRUNCATE will have to be solved as
part of other DDL in the future. I do have some ideas what to do with
DDL but I don't plan to implement them in the initial patch.

--
Petr Jelinek http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services