Re: Table AM Interface Enhancements

On Mon, Apr 15, 2024 at 12:37 PM Pavel Borisov <pashkin.elfe@gmail.com> wrote:
> In my understanding, the downside of 041b96802ef is bringing read_stream* things from being heap-only-related up to
thelevel of acquire_sample_rows() that is not supposed to be tied to heap. And changing *_analyze_next_block() function
signatureto use ReadStream explicitly in the signature. 

I don't think that really clarifies anything. The ReadStream is
basically just acting as a wrapper for a stream of block numbers, and
the API took a BlockNumber before. So why does it make any difference?

If I understand correctly, Alexander thinks that, before 041b96802ef,
the block number didn't necessarily have to be the physical block
number on disk, but could instead be any 32-bit quantity that the
table AM wanted to pack into the block number. But I don't think
that's true, because acquire_sample_rows() was already passing those
block numbers to PrefetchBuffer(), which already requires physical
block numbers.

--
Robert Haas
EDB: http://www.enterprisedb.com