Re: AWS forcing PG upgrade from v9.6 a disaster

[Christophe Pettus]

> On May 30, 2021, at 20:07, Dean Gibson (DB Administrator) 
> <postgre...@mailpen.com> wrote:
> The first two JOINs are not the problem, & are in fact retained in my 
> solution.  The problem is the third JOIN, where "fips_county" from "County" 
> is actually matched with the corresponding field from the "zip_code" VIEW.  
> Works fine, if you don't mind the performance impact in v10 & above.  It has 
> now been rewritten, to be a sub-query for an output field.  Voila !  Back to 
> sub-second query times.

If, rather than a subquery, you explicitly called out the join criteria with 
ON, did it have the same performance benefit?