Re: Hot Standby: First integrated patch

On Sat, Oct 18, 2008 at 4:11 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>
> On Fri, 2008-10-17 at 16:47 -0400, Merlin Moncure wrote:
>> On Fri, Oct 17, 2008 at 10:38 AM, Simon Riggs <simon(at)2ndquadrant(dot)com> wrote:
>> >
>> > First integrated patch for Hot Standby, allowing queries to be executed
>> > while in recovery mode.
>> >
>> > The patch tests successfully with the enclosed files:
>> > * primary_setup_test.sql - run it on primary node
>> > * standby_allowed.sql - run on standby - should all succeed
>> > * standby_disallowed.sql - run on standby - should all fail
>> > plus other manual testing.
>> >
>> > This is still WIP - its good enough to release for comments, though I am
>> > not yet confident enough to claim it bug free.
>> >
>> > What this doesn't do YET:
>> > * cope fully with subxid cache overflows (some parts still to add)
>> > * cope with prepared transactions on master
>> > * work correctly when running queries AND replaying WAL
>> > * work correctly with regard to AccessExclusiveLocks, which should
>> > prevent access to tables
>> >
>> > These last four points are what I'm working on over the next two weeks,
>> > plus any other holes people point out along the way. I have worked out
>> > designs for most of these aspects and will discuss them on -hackers,
>> > though most design notes are in the Wiki. I'm still looking into
>> > prepared transactions.
>> >
>> > Comments appreciated.
>>
>> It appears to be working, at least in some fashion. The supplied
>> tests all pass.
>
> Cool
>
> Thanks for testing so far.
>
>> At first glance it seems like I have to force changes to the standby
>> with pg_switch_xlog().
>>
>> hmm.
>
> You'll have to explain some more. Normally files don't get sent until
> they are full, so yes, you would need to do a pg_switch_xlog().
>
> This is not "streaming replication". Others are working on that.

right...this was expected. less the missing parts, things are working
very well.

merlin