crash-safe visibility map, take five

On Wed, Mar 30, 2011 at 8:52 AM, Heikki Linnakangas
<heikki(dot)linnakangas(at)enterprisedb(dot)com> wrote:
>> Another question:
>> To address the problem in
>> http://archives.postgresql.org/pgsql-hackers/2010-02/msg02097.php
>> , should we just clear the vm before the log of insert/update/delete?
>> This may reduce the performance, is there another solution?
>
> Yeah, that's a straightforward way to fix it. I don't think the performance
> hit will be too bad. But we need to be careful not to hold locks while doing
> I/O, which might require some rearrangement of the code. We might want to do
> a similar dance that we do in vacuum, and call visibilitymap_pin first, then
> lock and update the heap page, and then set the VM bit while holding the
> lock on the heap page.

Here's an attempt at implementing the necessary gymnastics.

Comments?

--
Robert Haas
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