Re: Table AM Interface Enhancements

Hi,

On Mon, Apr 8, 2024 at 12:40 AM Andres Freund <andres@anarazel.de> wrote:
> On 2024-03-30 23:33:04 +0200, Alexander Korotkov wrote:
> > I've pushed 0001, 0002 and 0006.
>
> I briefly looked at 27bc1772fc81 and I don't think the state post this commit
> makes sense. Before this commit another block based AM could implement analyze
> without much code duplication. Now a large portion of analyze.c has to be
> copied, because they can't stop acquire_sample_rows() from calling
> heapam_scan_analyze_next_block().
>
> I'm quite certain this will break a few out-of-core AMs in a way that can't
> easily be fixed.

I was under the impression there are not so many out-of-core table
AMs, which have non-dummy analysis implementations.  And even if there
are some, duplicating acquire_sample_rows() isn't a big deal.

But given your feedback, I'd like to propose to keep both options
open.  Turn back the block-level API for analyze, but let table-AM
implement its own analyze function.  Then existing out-of-core AMs
wouldn't need to do anything (or probably just set the new API method
to NULL).

> And even for non-block based AMs, the new interface basically requires
> reimplementing all of analyze.c.
.
Non-lock base AM needs to just provide an alternative implementation
for what acquire_sample_rows() does.  This seems like reasonable
effort for me, and surely not reimplementing all of analyze.c.