Horton

Re: Change GUC hashtable to use simplehash?

John Naylor <johncnaylorls@gmail.com>

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From: John Naylor <johncnaylorls@gmail.com>
To: jian he <jian.universality@gmail.com>
Cc: Jeff Davis <pgsql@j-davis.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Gurjeet Singh <gurjeet@singh.im>, pgsql-hackers@postgresql.org
Date: 2024-01-03T14:12:46Z
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

On Tue, Jan 2, 2024 at 6:56 AM jian he <jian.universality@gmail.com> wrote:
>
> My local computer is slow. but here is the test results:
>
> select * from bench_cstring_hash_aligned(100000);        7318.893 ms
> select * from bench_cstring_hash_unaligned(100000);    10383.173 ms
> select * from bench_pgstat_hash(100000);                       4474.989 ms
> select * from bench_pgstat_hash_fh(100000);                  9192.245 ms
> select * from bench_string_hash(100000);                        2048.008 ms

This presents a 2x to 5x slowdown, so I'm skeptical this is typical --
 what kind of platform is. For starters, what CPU and compiler?