Re: Adding skip scan (including MDAM style range skip scan) to nbtree

On 11.03.2025 18:52, Peter Geoghegan wrote:
> On Sat, Mar 8, 2025 at 11:43 AM Peter Geoghegan <pg(at)bowt(dot)ie> wrote:
>> I plan on committing this one soon. It's obviously pretty pointless to
>> make the BTMaxItemSize operate off of a page header, and not requiring
>> it is more flexible.
> Committed. And committed a revised version of "Show index search count
> in EXPLAIN ANALYZE" that addresses the issues with non-parallel-aware
> index scan executor nodes that run from a parallel worker.
>
Hi, reviewing the code I noticed that you removed the
parallel_aware check for DSM initialization for BitmapIndexScan,
IndexScan, IndexOnlyScan,
but you didn't do the same in the ExecParallelReInitializeDSM function
and I can't figure out why to be honest. I think it might be wrong or
I'm missing something.

As I see, it might be necessary if the parallel executor needs to
reinitialize the shared memory state before launching a fresh batches of
workers (it is based on
the comment of the ExecParallelReinitialize function), and when it
happens all child nodes reset their state (see the comment next to the
call to the ExecParallelReInitializeDSM
function).

So, what do you think? Should the check be removed in the
ExecParallelReInitializeDSM function too?

--
Regards,
Alena Rybakina
Postgres Professional