Re: testing HS/SR - 1 vs 2 performance

On Sun, 2010-04-25 at 13:51 -0400, Tom Lane wrote:
> Simon Riggs <simon@2ndQuadrant.com> writes:
> > On Sun, 2010-04-25 at 13:33 -0400, Tom Lane wrote:
> >> If you like I'll have a go at rewriting the comments for this patch,
> >> because I am currently thinking that the problem is not so much with
> >> the code as with the poor explanation of what it's doing.  Sometimes
> >> the author is too close to the code to understand why other people
> >> have a hard time understanding it.
>
> > That would help me, thank you.
>
> OK.  You said you were currently working some more on the patch, so
> I'll wait for v3 and then work on it.

v3 attached

Changes:
* Strange locking in KnownAssignedXidsAdd() moved to RecordKnown...
* KnownAssignedXidsAdd() reordered, assert-ish code added
* Tail movement during snapshots no longer possible
* Tail movement during xid removal added to KnownAssignedXidsSearch()
* Major comment hacking

Little bit rough, definitely needs a re-read of all comments, so good
time to send over.

--
 Simon Riggs           www.2ndQuadrant.com