Hi Joel,
Here are my two cents.
> 1. Who are the current users of 32-bit PostgreSQL?
Pretty much any embedded system that uses just a few GB of memory may
win from using a 32-bit processor (not necessarily in terms of
performance, maybe in terms of price). Think of WiFi-routers, smart
TVs, 3D printers, etc.
Generally speaking it's hard to give an exact answer due to lack of
"telemetry" in PostgreSQL.
> 2. Among these users, how many are upgrading to new major versions?
I would guess it very much depends on the product and manufacturer. I
wouldn't assume though that users of 32-bit systems don't do major
upgrades. (Not to mention that it's beneficial for us to test the code
on 32-bit systems.)
> 3. For how many of these users is performance critical?
Depends on how you define performance. Performance of a single OLTP
query is important. The performance of the upgrade procedure is
probably not that important. The ability of processing a lot of data
is probably also not extremely important, at least I wouldn't expect a
lot of data and/or fast storage devices on 32-bit systems.
--
Best regards,
Aleksander Alekseev