Re: [HACKERS] loading libraries on Postmaster startup

Tom Lane wrote:
> Joe Conway <mail(at)joeconway(dot)com> writes:
>>[ what about autoloading libraries into the postmaster? ]
>
> I can see a couple possible downsides: (a) the library might have some
> weird behavior across fork boundaries; (b) the additional memory space
> that has to be duplicated into child processes will cost something per
> child launch, even if the child never uses it. But these are only
> arguments that it might not *always* be a prudent thing to do, not that
> we shouldn't give the DBA the tool to do it if he wants. So fire away.

Here is a patch for the above, including a documentation update. It
creates a new GUC variable "preload_libraries", that accepts a list in
the form:

preload_libraries = '$libdir/mylib1:initfunc,$libdir/mylib2'

If ":initfunc" is omitted or not found, no initialization function is
executed, but the library is still preloaded. If "$libdir/mylib" isn't
found, the postmaster refuses to start.

In my testing with PL/R, it reduces the first call to a PL/R function
(after connecting) from almost 2 seconds, down to about 8 ms.

If there are no objections, please apply.

Thanks,

Joe