Is *fast* 32-bit support still important?

Hello hackers,

I would like your help to collectively try to answer these three questions:

1. Who are the current users of 32-bit PostgreSQL?

2. Among these users, how many are upgrading to new major versions?

3. For how many of these users is performance critical?

This came up during ongoing work on optimizing numeric_mul [1].

To me, it's non-obvious whether introducing `#if SIZEOF_DATUM < 8` with
separate 32-bit and 64-bit code paths is worthwhile to maintain performance
for both.

Knowing more about $subject can hopefully help us reason about how much
additional code complication is justifiable for *fast* 32-bit support.

I checked the archives but only found a discussion on *dropping* 32-bit support
[2], which is a different topic.

Thanks for input!

/Joel

[1] https://postgr.es/m/9d8a4a42-c354-41f3-bbf3-199e1957db97@app.fastmail.com
[2] https://postgr.es/m/0a71b43129fb447988f152941e1dbcb3@nidsa.net