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>, Heikki Linnakangas <hlinnaka@iki.fi>
Cc: Junwang Zhao <zhjwpku@gmail.com>, jian he <jian.universality@gmail.com>, Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>, Gurjeet Singh <gurjeet@singh.im>, pgsql-hackers@postgresql.org
Date: 2024-01-20T00:13:18Z
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 Fri, 2024-01-19 at 13:38 -0800, Jeff Davis wrote:
> One post-commit question on 0aba255440: why do
> haszero64(pg_bswap64(chunk)) rather than just haszero64(chunk)? How
> does byteswapping affect whether a zero byte exists or not?

I missed that it was used later when finding the rightmost one
position.

The placement of the comment was slightly confusing. Is:

  haszero64(pg_bswap64(chunk)) == pg_bswap64(haszero64(chunk))

? If so, perhaps we can do the byte swapping outside of the loop, which
might save a few cycles on longer strings and would be more readable.

Regards,
	Jeff Davis