RE: Logical replication 'invalid memory alloc request size 1585837200' after upgrading to 17.5

Dear Sawada-san, Amit,

> > It can impact the performance for large transactions with fewer
> > invalidations, especially the ones which has spilled changes because
> > it needs to traverse the entire list of changes again at the end.
>
> Agreed.
>
> > The
> > other idea would be to add new member(s) in ReorderBufferTXN to
> > receive distributed invalidations. For adding the new member in
> > ReorderBufferTXN: (a) in HEAD, it should be okay, (b) for
> > backbranches, we may be able to add at the end, but we should check if
> > there are any extensions using sizeof(ReorderBufferTxn) and if they
> > are using what we need to do.
>
> If we can make sure that that change won't break the existing
> extensions, I think this would be the most reasonable solution.

Based on the discussion, I created PoC for master/PG17. Please see attached.
The basic idea is to introduce the new queue which only contains distributed inval
messages. Contents are consumed at end of transactions. I feel some of codes can
be re-used so that internal functions are introduced. At least, it could pass
regression tests and workloads discussed here.

Best regards,
Hayato Kuroda
FUJITSU LIMITED