Re: 64-bit hash function for hstore and citext data type

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>

To: Andrew Gierth <andrew@tao11.riddles.org.uk>

Cc: Tomas Vondra <tomas.vondra@2ndquadrant.com>, amul sul <sulamul@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>

Date: 2018-11-23T19:05:17Z

Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

Fix hstore hash function for empty hstores upgraded from 8.4.
- e5a6ae97effe 9.4.21 landed
- bcbb682786a3 10.7 landed
- 8087788f6ade 9.5.16 landed
- 239abfff12a4 9.6.12 landed
- 02e669c0f7dd 11.2 landed
- d5890f49da6a 12.0 landed
Add a 64-bit hash function for type hstore.
- eb6f29141bed 12.0 landed
Add a 64-bit hash function for type citext.
- 48c41fa97480 12.0 landed
Introduce 64-bit hash functions with a 64-bit seed.
- 81c5e46c490e 11.0 cited

I wrote:
> Andrew Gierth <andrew@tao11.riddles.org.uk> writes:
>> I'm inclined to fix this in hstoreUpgrade rather than complicate
>> hstore_hash with historical trivia. Also there have been no field
>> complaints - I guess it's unlikely that there is much pg 8.4 hstore data
>> in the wild that anyone wants to hash.

> Changing hstoreUpgrade at this point seems like wasted/misguided effort.

Oh, cancel that --- I was having a momentary brain fade about how that
function is used.  I agree your proposal is sensible.

			regards, tom lane