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

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От Amit Kapila
Тема Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions
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Msg-id CAA4eK1LKHs4Jd-6XvLdManqw7YmeC6jg+dFeF=SJxxPFC9UAHQ@mail.gmail.com
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Ответ на Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions  (Dilip Kumar <dilipbalaut@gmail.com>)
Ответы Re: PATCH: logical_work_mem and logical streaming of large in-progress transactions  (Dilip Kumar <dilipbalaut@gmail.com>)
Список pgsql-hackers
On Sun, Jul 5, 2020 at 4:47 PM Dilip Kumar <dilipbalaut@gmail.com> wrote:
>
> On Sat, Jul 4, 2020 at 11:35 AM Amit Kapila <amit.kapila16@gmail.com> wrote:
> >
>
> > 9.
> > +ReorderBufferHandleConcurrentAbort(ReorderBuffer *rb, ReorderBufferTXN *txn,
> > {
> > ..
> > + ReorderBufferToastReset(rb, txn);
> > + if (specinsert != NULL)
> > + ReorderBufferReturnChange(rb, specinsert);
> > ..
> > }
> >
> > Why do we need to do these here when we wouldn't have been done for
> > any exception other than ERRCODE_TRANSACTION_ROLLBACK?
>
> Because we are handling this exception "ERRCODE_TRANSACTION_ROLLBACK"
> gracefully and we are continuing with further decoding so we need to
> return this change back.
>

Okay, then I suggest we should do these before calling stream_stop and
also move ReorderBufferResetTXN after calling stream_stop  to follow a
pattern similar to try block unless there is a reason for not doing
so.  Also, it would be good if we can initialize specinsert with NULL
after returning the change as we are doing at other places.

> > 10.  I have got the below failure once.  I have not investigated this
> > in detail as the patch is still under progress.  See, if you have any
> > idea?
> > #   Failed test 'check extra columns contain local defaults'
> > #   at t/013_stream_subxact_ddl_abort.pl line 81.
> > #          got: '2|0'
> > #     expected: '1000|500'
> > # Looks like you failed 1 test of 2.
> > make[2]: *** [check] Error 1
> > make[1]: *** [check-subscription-recurse] Error 2
> > make[1]: *** Waiting for unfinished jobs....
> > make: *** [check-world-src/test-recurse] Error 2
>
> Even I got the failure once and after that, it did not reproduce.  I
> have executed it multiple time but it did not reproduce again.  Are
> you able to reproduce it consistently?
>

No, I am also not able to reproduce it consistently but I think this
can fail if a subscriber sends the replay_location before actually
replaying the changes.  First, I thought that extra send_feedback we
have in apply_handle_stream_commit might have caused this but I guess
that can't happen because we need the commit time location for that
and we are storing the same at the end of apply_handle_stream_commit
after applying all messages.  I am not sure what is going on here.  I
think we somehow need to reproduce this or some variant of this test
consistently to find the root cause.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com



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