Re: Curing plpgsql's memory leaks for statement-lifespan values

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> Tom Lane wrote:
>> Although this is in principle a bug fix, it's invasive enough that I'd
>> be pretty hesitant to back-patch it, or even to stick it into HEAD
>> post-beta.  I'm inclined to sign it up for the next commitfest instead.

> Do we have a backpatchable fix for the reported problem?  If so, then it
> seems a good tradeoff to install this more invasive fix in HEAD only and
> apply the simpler fix to back branches.  Otherwise, is the proposal to
> leave the bug unfixed in back branches?

The latter is what I was thinking.  Given that issues like this have been
there, and gone unreported, since we invented subtransactions, I do not
feel too awful about not fixing it in existing branches.  It's possible
that we could fix just the one issue originally complained of with a
smaller patch, but I don't find that approach attractive, because it was
also a small leak.  The case that seemed nastiest to me is that a FOREACH
... IN ARRAY loop will leak a copy of the entire array if an error causes
control to be thrown out of exec_stmt_foreach_a.  That could be a lot more
leaked data than the querystring of an EXECUTE.

I suppose that a fix based on putting PG_TRY blocks into all the affected
functions might be simple enough that we'd risk back-patching it, but
I don't really want to go that way.
        regards, tom lane