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

On Tue, Aug 4, 2020 at 12:42 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Tue, Aug 4, 2020 at 10:12 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
>
> > 4. I think we can explain the problems (like we can see the wrong
> > tuple or see two versions of the same tuple or whatever else wrong can
> > happen, if possible with some example) related to concurrent aborts
> > somewhere in comments.
>
> Done
>

I have slightly modified the comment added for the above point and
apart from that added/modified a few comments at other places. I have
also slightly edited the commit message.

@@ -2196,6 +2778,7 @@ ReorderBufferAddNewTupleCids(ReorderBuffer *rb,
TransactionId xid,
change->lsn = lsn;
change->txn = txn;
change->action = REORDER_BUFFER_CHANGE_INTERNAL_TUPLECID;
+ change->txn = txn;

This change is not required as the same information is assigned a few
lines before. So, I have removed this change as well. Let me know
what you think of the above changes?

Can we add a test for incomplete changes (probably with toast
insertion but we can do it for spec_insert case as well) in
ReorderBuffer such that it needs to first serialize the changes and
then stream it? I have manually verified such scenarios but it is
good to have the test for the same.

--
With Regards,
Amit Kapila.