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

On 02.08.2011 15:18, Simon Riggs wrote:
> On Tue, Aug 2, 2011 at 12:43 PM, Heikki Linnakangas
> <heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>> On 02.08.2011 14:36, Simon Riggs wrote:
>> Actually I think we can append the new information to the end of the page
>> split record, so that an old version server can read WAL generated by new
>> version, too.
>
> Not sure how that would work. Lengths, CRCs?
>
> Or do you mean we will support 2 versions, have them both called the
> same thing, just resolve which is which by the record length. Don't
> like that.

Here's a patch to do what I meant. The new fields are stored at the very
end of the WAL record, and you check the length to see if they're there
or not. The nice thing about this is that it's compatible in both
directions.

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