Re: how do you call one pltcl function from another?

Jonathan Ellis wrote:
> > You need to call it via SPI like
> >
> > spi_exec "select meta_class($1) as retval"
> > return $retval
>
> What kind of performance hit is there doing this vs two plpgsql functions?
> IIANM, you're creating two separate tcl interpreters this way, which seems
> expensive.

You are actually calling the same interpreter again through
the SPI interface (parser, planner, optimizer, executor).
Really expensive.

Someone can skip anything but the executor by preparing a
saved plan, but that's still a waste of CPU. At the very
least, calling one function from the other is expensive in
any procedural language, that must use a general solution
because the called function could be defined in any language.

Jan

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