Horton

Re: Change GUC hashtable to use simplehash?

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

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: John Naylor <johncnaylorls@gmail.com>, Jeff Davis <pgsql@j-davis.com>, Gurjeet Singh <gurjeet@singh.im>, pgsql-hackers@postgresql.org
Date: 2023-11-22T20:56:21Z
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 →

  1. Silence warning in older versions of Valgrind

  2. Revert "Speed up tail processing when hashing aligned C strings, take two"

  3. Speed up tail processing when hashing aligned C strings, take two

  4. Teach fasthash_accum to use platform endianness for bytewise loads

  5. Add macro to disable address safety instrumentation

  6. Convert uses of hash_string_pointer to fasthash equivalent

  7. Speed up tail processing when hashing aligned C strings

  8. Add helper functions for dshash tables with string keys.

  9. Fix warnings in cpluspluscheck

  10. Further cosmetic review of hashfn_unstable.h

  11. Simplify initialization of incremental hash state

  12. Add optimized C string hashing

  13. Add inline incremental hash functions for in-memory use

  14. Make all Perl warnings fatal

Andres Freund <andres@anarazel.de> writes:
> On 2023-11-21 16:42:55 +0700, John Naylor wrote:
>> The strlen call required for hashbytes() is not free. The lack of
>> mixing in the (probably inlined after 0001) previous hash function can
>> remedied directly, as in the attached:

> I doubt this is a good hashfunction. For short strings, sure, but after
> that...  I don't think it makes sense to reduce the internal state of a hash
> function to something this small.

GUC names are just about always short, though, so I'm not sure you've
made your point?  At worst, maybe this with 64-bit state instead of 32?

			regards, tom lane