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

On Wed, Jul 8, 2020 at 7:31 PM Ajin Cherian <itsajin(at)gmail(dot)com> wrote:
>
> I was going through this thread and testing and reviewing the patches, I think this is a great feature to have and one which customers would appreciate. I wanted to help out, and I saw a request for a test patch for a GUC to always enable streaming on logical replication. Here's one on top of patchset v31, just in case you still need it. By default the GUC is turned on, I ran the regression tests with it and didn't see any errors.
>

Thanks for showing the interest in patch. How have you ensured that
streaming is happening? I don't think the proposed patch can ensure
it for every case because we also rely on logical_decoding_work_mem to
decide whether to stream/spill, see ReorderBufferCheckMemoryLimit. I
think with your patch it will allow streaming for cases where we have
large amount of WAL to decode.

I feel you need to add some DEBUG messages (or some other way) to
ensure that all existing and new test cases related to logical
decoding will perform the streaming.

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