Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions

On Mon, Jun 22, 2020 at 5:26 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Mon, Jun 22, 2020 at 4:41 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> >
> > On Mon, Jun 22, 2020 at 4:26 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > >
> > > On Thu, Jun 18, 2020 at 9:02 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
> > > >
> > > > Yes, I have made the changes. Basically, now I am only using the
> > > > XLOG_XACT_INVALIDATIONS for generating all the invalidation messages.
> > > > So whenever we are getting the new set of XLOG_XACT_INVALIDATIONS, we
> > > > are directly appending it to the txn->invalidations. I have tested
> > > > the XLOG_INVALIDATIONS part but while sending this mail I realized
> > > > that we could write some automated test for the same.
> > > >
> > >
> > > Can you share how you have tested it?
> >
> > I just ran create index concurrently and decoded the changes.
> >
>
> Hmm, I think that won't reproduce the exact problem. What I wanted
> was to run another command after "create index concurrently" which
> depends on that and see if the decoding fails by removing the
> XLOG_INVALIDATIONS code. Once you get some failure, you can apply the
> 0002 patch and see if the test is passed?

Okay, I will test that.

> >
> > > @@ -2012,8 +2014,6 @@ ReorderBufferForget(ReorderBuffer *rb,
> > > TransactionId xid, XLogRecPtr lsn)
> > > if (txn->base_snapshot != NULL && txn->ninvalidations > 0)
> > > ReorderBufferImmediateInvalidation(rb, txn->ninvalidations,
> > > txn->invalidations);
> > > - else
> > > - Assert(txn->ninvalidations == 0);
> > >
> > > Why this Assert is removed?
> >
> > Even if the base_snapshot is NULL, now we are collecting the
> > txn->invalidation.
> >
>
> But there doesn't seem to be any check even before this patch which
> directly prohibits accumulating invalidations in DecodeCommit. We
> have check for base_snapshot in ReorderBufferCommit. Did you get any
> failure with that check?

Because earlier ReorderBufferForget for toptxn will be called if the
top transaction is aborted and in abort case, we are not logging any
invalidation so that will be 0. However same is not true now.

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