Re: Memory leaks

Greg Copeland <greg(at)copelandconsulting(dot)net> writes:
> On Tue, 2002-10-22 at 17:09, Tom Lane wrote:
>> Yes, this has been dealt with before.

> What tools, aside from noggin v1.0, did they use? Do we know?

s/they/me/ ... none. But I don't know of any that I think would be
useful.

> I then moved on to psql, again, just for fun. Here, I'm thinking that I
> started to find some other leaks...but again, I've not spent any real
> time on it. So again, I'm not really sure it they are meaningful at
> this point.

psql might well have some internal leaks; the backend memory-context
design doesn't apply to it.

>> Possibly the best answer is to integrate the memory-context notion into
>> those modules; if they did most of their work in a temp context that
>> could be freed once per PL statement or so, the problems would pretty
>> much go away.

> Interesting. Having not looked at memory management schemes used in the
> pl implementations, can you enlighten me by what you mean by "integrate
> the memory-context notion"? Does that mean they are not using
> palloc/pfree stuff?

Not everywhere. plpgsql is full of malloc's and I think the other PL
modules are too --- and that's not to mention the allocation policies of
the perl, tcl, etc, language interpreters. We could use a thorough
review of that whole area.

> Well, the thing that really got my attention is that dmalloc is
> reporting frees on null pointers.

AFAIK that would dump core on many platforms (it sure does here...),
so I don't think I believe it without seeing chapter and verse. But
if you can point out where it's really happening, then we must fix it.

regards, tom lane