Re: [PATCH] Microvacuum for gist.

On Wed, Sep 16, 2015 at 8:36 AM, Teodor Sigaev <teodor(at)sigaev(dot)ru> wrote:

> But It seems to me that it would be better to rewrite all mentions of
>> TupleDelete to MultiDelete in gist code.
>>
>
> Sure. Patch is attached, and it changes WAL format, so be carefull with
> testing.
> Please, have a look.
>
> Also in attach scripts reproduce bug from Jeff's report:
> g.pl - creates and fills test table
> w.pl - worker, could run in several session
>
> Usage
> perl g.pl | psql contrib_regression
> perl w.pl | psql contrib_regression | grep 'UPDATE 0'
>
> and killall -9 postgres while w.pl is running. Recovery will fail with
> high probability.
>
> Thank you, Jeff, for report.

Thanks, that seems to have fixed it.

But I don't understand this comment:

+ /*
+ * While we delete only one tuple at once we could mix calls
+ * PageIndexTupleDelete() here and PageIndexMultiDelete() in
+ * gistRedoPageUpdateRecord()
+ */

Does this mean:

Since we delete only one tuple per WAL record here, we can call
PageIndexTupleDelete() here and re-play it with PageIndexMultiDelete() in
gistRedoPageUpdateRecord()

Thanks,

Jeff