| From: | Jeff Davis <pgsql(at)j-davis(dot)com> |
|---|---|
| To: | John Naylor <johncnaylorls(at)gmail(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi> |
| Cc: | Junwang Zhao <zhjwpku(at)gmail(dot)com>, jian he <jian(dot)universality(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Gurjeet Singh <gurjeet(at)singh(dot)im>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Change GUC hashtable to use simplehash? |
| Date: | 2024-01-20 00:13:18 |
| Message-ID: | 09924cd6c49935d5e9bba5cd40bec28c605d7c2e.camel@j-davis.com |
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| Lists: | pgsql-hackers |
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
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