Re: Performance degradation of REFRESH MATERIALIZED VIEW

Hi,

On 2021-04-26 15:31:02 +0200, Tomas Vondra wrote:
> I'm not sure what to do about this :-( I don't have any ideas about how to
> eliminate this overhead, so the only option I see is reverting the changes
> in heap_insert. Unfortunately, that'd mean inserts into TOAST tables won't
> be frozen ...

ISTM that the fundamental issue here is not that we acquire pins that we
shouldn't, but that we do so at a much higher frequency than needed.

It's probably too invasive for 14, but I think it might be worth exploring
passing down a BulkInsertState in nodeModifyTable.c's table_tuple_insert() iff
the input will be more than one row.

And then add the vm buffer of the target page to BulkInsertState, so that
hio.c can avoid re-pinning the buffer.

Greetings,

Andres Freund