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

On Mon, Dec 2, 2019 at 2:02 PM Dilip Kumar <dilipbalaut(at)gmail(dot)com> wrote:
>
> On Sun, Dec 1, 2019 at 7:58 AM Michael Paquier <michael(at)paquier(dot)xyz> wrote:
> >
> > On Fri, Nov 22, 2019 at 01:18:11PM +0530, Dilip Kumar wrote:
> > > I have rebased the patch on the latest head and also fix the issue of
> > > "concurrent abort handling of the (sub)transaction." and attached as
> > > (v1-0013-Extend-handling-of-concurrent-aborts-for-streamin) along with
> > > the complete patch set. I have added the version number so that we
> > > can track the changes.
> >
> > The patch has rotten a bit and does not apply anymore. Could you
> > please send a rebased version? I have moved it to next CF, waiting on
> > author.
>
> I have rebased the patch set on the latest head.
>
> Apart from this, there is one issue reported by my colleague Vignesh.
> The issue is that if we use more than two relations in a transaction
> then there is an error on standby (no relation map entry for remote
> relation ID 16390). After analyzing I have found that for the
> streaming transaction an "is_schema_sent" flag is kept in
> ReorderBufferTXN. And, I think that is done so that we can send the
> schema for each transaction stream so that if any subtransaction gets
> aborted we don't lose the logical WAL for that schema. But, this
> solution has induced a very basic issue that if a transaction operate
> on more than 1 relation then after sending the schema for the first
> relation it will mark the flag true and the schema for the subsequent
> relations will never be sent.
>

How about keeping a list of top-level xids in each RelationSyncEntry?
Basically, whenever we send the schema for any transaction, we note
that in RelationSyncEntry and at abort time we can remove xid from the
list. Now, whenever, we check whether to send schema for any
operation in a transaction, we will check if our xid is present in
that list for a particular RelationSyncEntry and take an action based
on that (if xid is present, then we won't send the schema, otherwise,
send it).

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