On 10/1/22 14:54, Christoph Moench-Tegeder wrote:
## Ron (ronljohnso...@gmail.com):
The question then is "why am I just now seeing the problem?" We've been
using v12 for two years, and it just happened.
The only recent change is that I upgraded it from RDS 12.10 to 12.11 a
couple of weeks ago.
That's correlation, but no proof for causality.
Right. But it is an important change which happened between job runs (the
22nd of each month).
Now that you've confirmed that you have indeed a mismatch between generic
and custom plan, you could compare those (EXPLAIN EXECUTE) and see
where the generic plan goes wrong.
I'll rerun the EXPLAIN EXECUTE with and without "plan_cache_mode =
force_custom_plan", and attach them in a reply some time soon.
Otherwise, prime suspects are bad
statistics (Were stats accurate before the update? How about now?
Ran VACUUM ANALYZE recently?
VACUUM yesterday at 04:00, and ANALYZE at 09:00, both from a cron job.
Manually ran ANALYZE last night during the dig into the problem.
If not, does it improve matters?)
Nope. Not one bit.
If would help if you could compare execution plans with plans from
before the update, but I guess you didn't document those?
So, since ANALYZE did not help.
--
Angular momentum makes the world go 'round.
