Re: [GENERAL] Is float8 a reference type?
| От | Tom Lane |
|---|---|
| Тема | Re: [GENERAL] Is float8 a reference type? |
| Дата | |
| Msg-id | 27465.1506184824@sss.pgh.pa.us обсуждение исходный текст |
| Ответ на | Re: [GENERAL] Is float8 a reference type? (Paul A Jungwirth <pj@illuminatedcomputing.com>) |
| Ответы |
Re: [GENERAL] Is float8 a reference type?
|
| Список | pgsql-general |
Paul A Jungwirth <pj@illuminatedcomputing.com> writes:
> Since I'm expecting ~10 million elements per array, it seems like
> skipping the conversion will have a real effect. I checked the
> assembly and do see a difference (on both Mac+clang and Linux+gcc).
I wonder whether you're using up-to-date Postgres headers (ones
where Float8GetDatum is a static inline function). For me, both
of those platforms recognize it as a no-op --- in fact, clang
turns a loop like
for (i = 0; i < n; i++) { datums[i] = Float8GetDatum(floats[i]); }
into something that looks suspiciously like an inlined, loop-unrolled
memcpy().
regards, tom lane
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