Re: BitmapHeapScan streaming read user and prelim refactoring - Mailing list pgsql-hackers

On Mon, Mar 25, 2024 at 12:07:09PM -0400, Melanie Plageman wrote:
> On Sun, Mar 24, 2024 at 06:37:20PM -0400, Melanie Plageman wrote:
> > On Sun, Mar 24, 2024 at 5:59 PM Tomas Vondra
> > <tomas.vondra@enterprisedb.com> wrote:
> > >
> > > BTW when you say "up to 'Make table_scan_bitmap_next_block() async
> > > friendly'" do you mean including that patch, or that this is the first
> > > patch that is not one of the independently useful patches.
> > 
> > I think the code is easier to understand with "Make
> > table_scan_bitmap_next_block() async friendly". Prior to that commit,
> > table_scan_bitmap_next_block() could return false even when the bitmap
> > has more blocks and expects the caller to handle this and invoke it
> > again. I think that interface is very confusing. The downside of the
> > code in that state is that the code for prefetching is still in the
> > BitmapHeapNext() code and the code for getting the current block is in
> > the heap AM-specific code. I took a stab at fixing this in v9's 0013,
> > but the outcome wasn't very attractive.
> > 
> > What I will do tomorrow is reorder and group the commits such that all
> > of the commits that are useful independent of streaming read are first
> > (I think 0014 and 0015 are independently valuable but they are on top
> > of some things that are only useful to streaming read because they are
> > more recently requested changes). I think I can actually do a bit of
> > simplification in terms of how many commits there are and what is in
> > each. Just to be clear, v9 is still reviewable. I am just going to go
> > back and change what is included in each commit.
> 
> So, attached v10 does not include the new version of streaming read API.
> I focused instead on the refactoring patches commit regrouping I
> mentioned here.

Attached v11 has the updated Read Stream API Thomas sent this morning
[1]. No other changes.

- Melanie

[1] https://www.postgresql.org/message-id/CA%2BhUKGJTwrS7F%3DuJPx3SeigMiQiW%2BLJaOkjGyZdCntwyMR%3DuAw%40mail.gmail.com