Comments on: Wishlist of PL/Perl Enhancements for PostgreSQL 8.5

By: TimBunce

TimBunce — Wed, 07 Oct 2009 22:13:49 +0000

I see your point. What’s needed is some equivalent of a “use” statement that can be put at the start of plperl functions. I have a few ideas – I’ll give it some thought. Thanks.

By: Peter Eisentraut

Peter Eisentraut — Wed, 07 Oct 2009 12:24:21 +0000

Item 1 could be controversial. It’s undoubtedly useful, but it creates an action at a distance that effectively invites users to create mutually incompatible PL/Perl installation. Ideally, you would want users to create libraries of reusable PL/Perl functions, but when those only work with certain at_init_do settings, then you create a big mess. Look at PHP; they have done something quite similar with their php.ini.

By: TimBunce

TimBunce — Tue, 06 Oct 2009 20:40:49 +0000

Suggested change: rename plperl.at_init_do to plperl.at_perl_init_do and add plperl.at_safe_init_do which would be similar but specify code to run when the Safe compartment is initialized. It could thus be set by per-user/per-role GUC.

By: TimBunce

TimBunce — Tue, 06 Oct 2009 20:03:15 +0000

It’s not fixed in 5.10.1. I’ve asked for an update on the status. Meanwhile I’ve added a comment on the ticket with a simple workaround that would be effective for plperl and that I’ll include in my changes.

By: Andrew G.

Andrew G. — Tue, 06 Oct 2009 12:31:29 +0000

Points 1-3 are primarily attempts to work around the lack of features that should have been in Safe.pm in the first place.

For comparison, in TCL if you create a safe interpreter using ::safe::interpCreate, then the safe interpreter can load modules etc. in the normal way, subject to (a) the specified mapping between host filenames and the virtual filenames seen inside the safe interpreter, and (b) the fact that the loaded modules are still running inside the safe interpreter and have no more access than it does.

A proper system of external interfaces for Safe would obviate the need for many of the features you are requesting.

Incidentally, is the sort{} + threads + Safe bug (#60374) fixed yet? (and if it is, why is it still open?)

By: TimBunce

TimBunce — Tue, 06 Oct 2009 08:40:27 +0000

Thank you, yes, I mean at the end of the process. I’m not sure what you mean by “Most of the rest of your points would be better addressed at the perl level”.

By: Zbigniew Lukasiak

Zbigniew Lukasiak — Tue, 06 Oct 2009 08:01:25 +0000

I don’t have anything smart to write here – but I wanted to express my support, especially for the point 1 above. It was a long time ago that I learned about PL/Perl and I was initially thrilled about the possibilities – but after I learned about the constraints for loading modules I realized that it’s application is very limited.

By: Andrew G.

Andrew G. — Tue, 06 Oct 2009 04:08:48 +0000

Currently PostgreSQL doesn’t execute END blocks at server shutdown

You do realize that this would be impossible, right? That interpreters are created per-connection and no interpreter state can be preserved past the end of the session (each session is a separate process)?

Most of the rest of your points would be better addresses at the perl level (Safe is a joke compared to, for example, TCL’s safe interpreters).