RE: Perform streaming logical transactions by background workers and parallel apply

On Tuesday, January 17, 2023 12:55 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>
> On Tue, Jan 17, 2023 at 8:59 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > On Tue, Jan 17, 2023 at 8:35 AM Masahiko Sawada
> <sawada(dot)mshk(at)gmail(dot)com> wrote:
> > >
> > > On Mon, Jan 16, 2023 at 3:19 PM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com>
> wrote:
> > > >
> > > > Okay, I have added the comments in get_transaction_apply_action()
> > > > and updated the comments to refer to the enum TransApplyAction
> > > > where all the actions are explained.
> > >
> > > Thank you for the patch.
> > >
> > > @@ -1710,6 +1712,7 @@ apply_handle_stream_stop(StringInfo s)
> > > }
> > >
> > > in_streamed_transaction = false;
> > > + stream_xid = InvalidTransactionId;
> > >
> > > We reset stream_xid also in stream_close_file() but probably it's no
> > > longer necessary?
> > >
> >
> > I think so.
> >
> > > How about adding an assertion in apply_handle_stream_start() to make
> > > sure the stream_xid is invalid?
> > >
> >
> > I think it would be better to add such an assert in
> > apply_handle_begin/apply_handle_begin_prepare because there won't be a
> > problem if we start_stream message even when stream_xid is valid.
> > However, maybe it is better to add in all three functions
> >
> (apply_handle_begin/apply_handle_begin_prepare/apply_handle_stream_star
> t).
> > What do you think?
> >
> > > ---
> > > It's not related to this issue but I realized that if the action
> > > returned by get_transaction_apply_action() is not handled in the
> > > switch statement, we do only Assert(false). Is it better to raise an
> > > error like "unexpected apply action %d" just in case in order to
> > > detect failure cases also in the production environment?
> > >
> >
> > Yeah, that may be better. Shall we do that as part of this patch only
> > or as a separate patch?
> >
>
> Please find attached the updated patches to address the above comments. I
> think we can combine and commit them as one patch as both are related.

Thanks for fixing these.
I have confirmed that all regression tests passed after applying the patches.
And the patches look good to me.

Best regards,
Hou zj