Status Report on Hot Standby

Bruce asked for 2 more weeks to get patches into shape for commit.

Current patch v8e is attached here. Ready for commit? Up to you.

My overall opinion is that it's in very good shape. Worth the community
including it in this release and spending further time on it. I'm happy
to stand by this going forwards.

First, *all* known problems are recorded on Wiki:
http://wiki.postgresql.org/wiki/Hot_Standby
Much time has been spent looking at correctness issues in particular.

All of Heikki's recommended refactorings have been completed and
debugged. In the last week, Gianni and I have resolved more than 20
issues/work items and we've reduced considerably the time for test
cycles. Testing has been by code inspection, bash testing, regression
test replay and specific feature tests. Special thanks to Gianni for
performing such a large range of strange sounding tests and to the rest
of the team's support in various ways.

There are a number of items still required

* Prepared Transactions - yes, its been on the list for a while, but
there's nothing weird there and now everything else is solid it should
take a couple of days to add

* Conflict resolution for when people are connected as database/user and
that database/user is dropped (recently raised) - some discussion needed

* Fixing client/server state bug related to error handling while idle in
transaction (which effects invalidation message handling also)

There are also a number of items I think we need to do, but are optional
and can be added as separate items over next couple of weeks

* Some simple performance tweaks, though works acceptably now

* Improved conflict resolution using deferred cancellation. I think this
is worth including and I have a fairly simple design.

The patch could benefit further from input from other various hackers,
what couldn't? It's time to put this in a shared repository (of some
kind) and make further changes to it in a controlled manner.

What now?

--
 Simon Riggs           www.2ndQuadrant.com
 PostgreSQL Training, Services and Support