Re: Hot standby and GiST page splits (was Re: WIP: Fast GiST index build)

On 01.08.2011 17:26, Simon Riggs wrote:
> On Mon, Aug 1, 2011 at 2:29 PM, Heikki Linnakangas
> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>> I believe we code acquire the locks in right order already, and the patch I
>> posted fixes the premature release of locks at page split.
>
> Your patch is good, but it does rely on the idea that we're logging
> the blocks in the same order they were originally locked. That's a
> good assumption, but I would like to see that documented for general
> sanity, or just mine at least.
>
> I can't really see anything in the master-side code that attempts to
> lock things in a specific sequence, which bothers me also.

All but the first page are unused pages, grabbed with either P_NEW or
from the FSM. gistNewBuffer() uses ConditionalLockBuffer() to guard for
the case that someone else chooses the same victim buffer, and picks
another page.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com