Re: PostrgeSQL vs oracle doing 1 million sqrts am I doing it wrong?

2014-08-06 22:07 GMT+02:00 James Cloos <cloos(at)jhcloos(dot)com>:

> >>>>> "ST" == Shaun Thomas <sthomas(at)optionshouse(dot)com> 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

exec_cast_value

>
> -JimC
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