Re: Material node doesn't show "Maximum Storage" for parallel workers

Hi David,

Thank you for the patch!
I reviewed v1. I confirmed the following, so LGTM.

- With debug_parallel_query = regress, the Storage line, which didn't
appear without the patch, is now shown.
- When run in parallel, the Storage lines for Workers 0 to 3 are shown,
and with parallel_leader_participation = on, the leader's line is
shown as well.

> 1eff8279d was added in v18, and you could argue this patch is a bug
> fix for the missing information in debug_parallel_query = regress, but
> also a new feature to show Material telemetry for parallel workers.
> Per how debug_parallel_query works, it's really the same thing.
>
> I think this should be master-only. No backpatch.

I agree with not backpatching this.

While reviewing, I noticed that ExecEndMemoize() overwrites the worker's
slot with memcpy(), so when the Gather is rescanned, only the stats from
the last execution remain. I plan to post a patch in a separate thread
to accumulate the stats instead.

Regards,
Tatsuya Kawata