Horton

Re: Change GUC hashtable to use simplehash?

Jeff Davis <pgsql@j-davis.com>

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From: Jeff Davis <pgsql@j-davis.com>
To: John Naylor <johncnaylorls@gmail.com>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Gurjeet Singh <gurjeet@singh.im>, pgsql-hackers@postgresql.org
Date: 2023-12-19T07:32:30Z
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

Attachments

On Mon, 2023-12-18 at 13:39 +0700, John Naylor wrote:
> For now just two:
> v10-0002 is Jeff's change to the search path cache, but with the
> chunked interface that I found to be faster.

Did you consider specializing for the case of an aligned pointer? If
it's a string (c string or byte string) it's almost always going to be
aligned, right?

I hacked up a patch (attached). I lost track of which benchmark we're
using to test the performance, but when I test in a loop it seems
substantially faster.

It reads past the NUL byte, but only to the next alignment boundary,
which I think is OK (though I think I'd need to fix the patch for when
maxalign < 8).

Regards,
	Jeff Davis