Re: PostrgeSQL vs oracle doing 1 million sqrts am I doing it wrong?
| От | Pavel Stehule |
|---|---|
| Тема | Re: PostrgeSQL vs oracle doing 1 million sqrts am I doing it wrong? |
| Дата | |
| Msg-id | CAFj8pRCbe+35gNygp3Gwvem21GRsJM9psxmaD2c0zZfD7MGSEA@mail.gmail.com обсуждение исходный текст |
| Ответ на | Re: PostrgeSQL vs oracle doing 1 million sqrts am I doing it wrong? (James Cloos <[email protected]>) |
| Список | pgsql-hackers |
2014-08-06 22:07 GMT+02:00 James Cloos <[email protected]>:
>>>>> "ST" == Shaun Thomas <[email protected]> writes:
ST> That said, the documentation here says FLOAT4 is an alias for REAL,
ST> so it's somewhat nonintuitive for FLOAT4 to be so much slower than
ST> FLOAT8, which is an alias for DOUBLE PRECISION.
There are some versions of glibc where doing certain math on double is
faster than doing it on float, depending on how things are compiled.
Maybe this is one of them?
no
It is plpgsql issue only. PL/pgSQL uses a generic cast via serialization to string and new parsing
It doesn't use a effective libc casting functions.
see https://github.com/postgres/postgres/blob/master/src/pl/plpgsql/src/pl_exec.c function
see https://github.com/postgres/postgres/blob/master/src/pl/plpgsql/src/pl_exec.c function
exec_cast_value
-JimC
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James Cloos <[email protected]> OpenPGP: 0x997A9F17ED7DAEA6
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