On Wed, Apr 15, 2020 at 08:55:53PM +0100, singh...@gmail.com wrote:
> We have an odd issue where specifying the same where clause twice causes PG
> to pick a much more efficent plan. We would like to know why.
> Query B (this is the 'fast' query):
> UPDATE problem_instance SET processed = false
>
> Starting with PostgreSQL 9.6, foreign keys are also used to help with
> join selectivity estimations. I see you have a suitable foreign key
> from the schema you posted. You might want to add that to the list of
> reasons to upgrade.
Apologies for the delay in response. I've had "PostgreSQL 9.6
