Re: Result Cache node shows per-worker info even for workers not launched

Amit Khandekar <amitdkhan.pg@gmail.com>

From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: David Rowley <dgrowleyml@gmail.com>
Cc: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2021-04-28T10:59:09Z
Lists: pgsql-hackers
On Wed, 28 Apr 2021 at 16:14, David Rowley <dgrowleyml@gmail.com> wrote:
> However, I did add 1 test that sets work_mem down to 64kB to ensure
> the eviction code does get some exercise. You'll notice that I pass
> "true" to explain_resultcache() to hide the hits and misses there.  We
> can't test the exact number of hits/misses/evictions there, but we can
> at least tell apart the zero and non-zero by how I coded
> explain_resultcache() to replace with Zero or N depending on if the
> number was zero or above zero.

Thanks for the explanation. I did realize after replying to Bharat
upthread, that I was wrong in assuming that the cache misses and cache
hits are always stable for non-parallel scans.



Commits

  1. Adjust EXPLAIN output for parallel Result Cache plans