[geos-devel] An Immodest Proposal

[Stephen Woodbridge]

Paul,

As part of the GEOS cleanup, why don't you restore the default 
malloc/free so after you have cleaned up everything, the system can then 
free() on the factory stuff instead of pfree() them.

-Steve W

Paul Ramsey wrote:
> So, moving the instantiation of geomFactory object into initGEOS did
> nothing for me, the object is still allocated by malloc, not palloc,
> perhaps because it's a global, so it's getting set up at library load
> time?
> 
> Putting the whole factory and creation process inside the function
> bodies could get very expensive, since the functions are called
> repetitively a lot, which means each call would do a newfactory,
> newgeo, destroygeom, destroyfactory (ack!).  This is presumably why
> the factory was made into a global outside the functions.
> 
> I'm at an impasse. If new/delete are overridden, when the end of a
> postgres comes along, the system will attempt to pfree the globals as
> it cleans up the library, and since the globals are malloc'ed,
> segfault ensues.
> 
> If we backtrack to not over-riding new/delete, then we have the
> problem of leaking the prepared objects at the end of each
> transaction.
> 
> P.
> 
> On Wed, Oct 1, 2008 at 11:08 AM, Paul Ramsey <pramsey at cleverelephant.ca> wrote:
>> So, using a longer lived memory context I can get right to the end of
>> a query before the segfault arrives. The segfault happens when
>> deleting a geometryfactory at the end, which tells me a couple things,
>> I think.
>>
>> First, those two std allocs that sneak in before we over-ride new are
>> related to the geometry factory. The segfault happens when we're
>> trying to pfree the geometryfactory.
>>
>> The offending code is this in geos_c.cpp:
>>
>> // NOTE: SRID will have to be changed after geometry creation
>> static const GeometryFactory *geomFactory =
>>        GeometryFactory::getDefaultInstance();
>>
>> This global geomFactory is called a number of times by WKB readers and
>> some other functions.  I wonder if we can initialize it in initGEOS
>> and clean it up in finishGEOS?
>>
>> It appears, that this is what used to happen? Here's the current code.
>>
>> void
>> finishGEOS ()
>> {
>>        // Nothing to do
>>        //delete geomFactory;
>> }
>>
>> Any help on the history behind this global?
>>
>> P.
>>
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