Re: Hot standby, prepared xacts, locks

On Wed, 2009-10-21 at 19:37 +0300, Heikki Linnakangas wrote:

> So, I'm quite eager to just revert all those lock_twophase_recover()
> changes, and always rely on the "grant lock to dummy proc, then
> release
> it in startup process" method. If we don't want to rely on that,
> PostPrepare_Locks is an example of how to transfer lock ownership from
> one process to another correctly.

Yes, I realised after I wrote it that PostPrepare already does that
switch, just been busy with other stuff to switch over the code.

I think we do need some special code because of handling whole lock
queues. i.e. if there is a backend requesting an AEL but a prepared xact
has it, the lock queue will initially be Backend->Startup and needs to
end up looking like Backend->DummyProc.

-- Simon Riggs           www.2ndQuadrant.com