Re: Question about MemoryContexts and functions that returns

Tom Lane wrote:
> Thomas Hallgren <thomas(at)tada(dot)se> writes:
>
>> As it turns out, I'm not supposed to allocate the returned tuple in the
>> caller context.
>>
>
> Where do you get that from? plpgsql and plperl both do it that way AFAICS.
>
> Are you testing in an --enable-cassert build? The memory-clobber
> behavior that that turns on is really essential for finding
> dangling-pointer problems ...
>
>

I use --enable-cassert. I don't think my problem is a dangling pointer.

I just created a dummy C-function that short circuits the
java_call_handler. It calls my real java function with the correct
parameters. When I register this function with language C and use it
instead of the normal function that calls via the java call handler,
there's no memory leak. It only leaks memory when I go through the call
handler. The call handler doesn't execute many lines of code and from
what I can tell, it doesn't manipulate contexts at all. Nor does it
allocate anything. Further more, I can prevent the leak by allocating
the returned tuple in a context of my own and free it on the next call.

Is there a difference in how the executor treat a C function and a
function using a call handler that can cause this behavior?

Regards,
Thomas Hallgren