Re: Replication slot stats misgivings

On Wed, Apr 28, 2021 at 12:49 PM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
>
> BTW regarding the commit f5fc2f5b23 that added total_txns and
> total_bytes, we add the reorder buffer size (i.g., rb->size) to
> rb->totalBytes but I think we should use the transaction size (i.g.,
> txn->size) instead:
>

You are right about the problem but I think your proposed fix also
won't work because txn->size always has current transaction size which
will be top-transaction in the case when a transaction has multiple
subtransactions. It won't include the subtxn->size. For example, you
can try to decode with below kind of transaction:
Begin;
insert into t1 values(1);
savepoint s1;
insert into t1 values(2);
savepoint s2;
insert into t1 values(3);
commit;

I think we can fix it by keeping track of total_size in toptxn as we
are doing for the streaming case in ReorderBufferChangeMemoryUpdate.
We can probably do it for non-streaming cases as well.

-- 
With Regards,
Amit Kapila.