Re: Decoding speculative insert with toast leaks memory

On Tue, Jun 1, 2021 at 10:21 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Jun 1, 2021 at 9:59 AM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Tue, Jun 1, 2021 at 9:53 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Mon, May 31, 2021 at 8:12 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > > >
> > > > On Mon, May 31, 2021 at 6:32 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > > > >
> > > > > I missed to do the test for streaming. I will to that tomorrow and reply back.
> > > >
> > > > For streaming transactions this issue is not there. Because this
> > > > problem will only occur if the last change is *SPEC INSERT * and after
> > > > that there is no other UPDATE/INSERT change because on that change we
> > > > are resetting the toast table. Now, if the transaction has only *SPEC
> > > > INSERT* without SPEC CONFIRM or any other INSERT/UPDATE then we will
> > > > not stream it. And if we get any next INSERT/UPDATE then only we can
> > > > select this for stream but in that case toast will be reset. So as of
> > > > today for streaming mode we don't have this problem.
> > > >
> > >
> > > What if the next change is a different SPEC_INSERT
> > > (REORDER_BUFFER_CHANGE_INTERNAL_SPEC_INSERT)? I think in that case we
> > > will stream but won't free the toast memory.
> >
> > But if the next change is again the SPEC INSERT then we will keep the
> > PARTIAL change flag set and we will not select this transaction for
> > stream right?
> >
>
> Right, I think you can remove the change related to stream xact and
> probably write some comments on why we don't need it for streamed
> transactions. But, now I have another question related to fixing the
> non-streamed case. What if after the missing spec_confirm we get the
> delete operation in the transaction? It seems
> ReorderBufferToastReplace always expects Insert/Update if we have
> toast hash active in the transaction.

Yeah, that looks like a problem, I will test this case.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com