On Sun, Dec 21, 2025 at 12:55 PM Peter Geoghegan <pg@bowt.ie> wrote:
> Attached is v5.
Attached is v6. I'm posting this a little earlier than planned in
order to make sure that the patch continues to apply cleanly against
HEAD (v5 stopped cleanly applying about a week back).
v6 focusses on simplifying the batch management code in
heapam_batch_getnext_tid. Importantly, heapam_batch_getnext_tid no
longer uses a loop to process items from the currently loaded batch/to
load the next batch. The control flow in heapam_batch_getnext_tid is a
lot simpler in general compared to v5.
I still haven't had time to produce an implementation of the "heap
buffer locking minimization" optimization that's clean enough to
present to the list. The heapam_batch_getnext_tid refactoring in v6 is
groundwork for that, though; the previous complicated loop-based
control flow in heapam_batch_getnext_tid made that harder. Hopefully
I'll manage to have that in shape in the next revision.
The corresponding "batch management" control flow used by the stream
callback (added by the second/prefetching patch) still needs to use a
loop -- that can't be avoided/actually makes sense. But I did manage
to make those parts a bit simpler and clearer for v6. Work remains to
simplify that stream callback control flow. We still need to invent
clear invariants that describe the relationship between
readPos/readBatch and streamPos/streamBatch. Some verifying assertions
would also go a long way towards making the readstream callback clean
and maintainable.
--
Peter Geoghegan
