Re: Proposal: Filter irrelevant change before reassemble transactions during logical decoding

> This is just an immature idea. I haven't started to implement it yet.
> Maybe it was designed this way because there
> are key factors that I didn't consider. So I want to hear everyone's
> opinions, especially the designers of logic decoding.

Attached is the patch I used to implement this optimization.
The main designs are as follows:
1. Added a callback LogicalDecodeFilterByRelCB for the output plugin.

2. Added this callback function pgoutput_table_filter for the pgoutput plugin.
Its main implementation is based on the table filter in the
pgoutput_change function.

3. After constructing a change and before Queue a change into a transaction,
use RelidByRelfilenumber to obtain the relation associated with the change,
just like obtaining the relation in the ReorderBufferProcessTXN function.

4. Relation may be a toast, and there is no good way to get its real
table relation
based on toast relation. Here, I get the real table oid through
toast relname, and
then get the real table relation.

5. This filtering takes into account INSERT/UPDATE/INSERT. Other
changes have not
been considered yet and can be expanded in the future.

6. The table filter in pgoutput_change and the get relation in
ReorderBufferProcessTXN
can be deleted. This has not been done yet. This is the next step.

Sincerely look forward to your feedback.
Regards, lijie