On 21/12/11 13:16, Martin J. Evans wrote:
On 21/12/11 13:05, Charles Jardine wrote:
I think I have found the resource drain which causes your
slow-down problem. Buffers implicitly allocated in the cache by
OCIDefineObject() need to be deallocated explicitly by
OCIObjectFree() 'when they are no longer needed'. This is
counter-intuitive, but it is documented in the reference
description of OCIDefineObject(), and has been since Oracle 8.
I have attached a demonstration patch against the trunk for you to
test. This patch is not fit to go into service. We need a logging
macro for OCIObjectFree().
If at any stage, you want a tester for any changes you've made to
the code please put me in the front of the queue.
Now I have found this resource drain, I feel happier about
submitting a patch intended to remove all resource drains from the
object/collection stuff. Expect me to be offering you something
bigger to test after the Christmas break.
Many thanks Charles. I will test this out.
As this was failing so badly for us the production code is now
actually pulling a flat result-set and munging it in Perl into the
arrays we required before converting to JSON (currently taking 7s
instead of 25s). This method does not leak any memory, does not
suffer from any performance degradation and is actually faster even
though it is pulling 10's of thousands more rows from the database
and having to process each one. Of course, the object/collection
method required a deep copy to get the actual data in Perl and that
added time too - I never really got to the bottom of why that was
so.
Our overriding goal is speed so whatever method is faster and uses
less resources will win for us. I'll try your patch out and see where
I get.
Thanks.
Martin
Certainly less sign of memory leakage.
Incidentally by accident I ran my first test example with perl 5.10.0 and then
I reran it when I realised on I'd made that mistake and my test example speeded
up from 11 to 12 seconds to 7 to 8 seconds. No idea what causes that.
With the real code we also see less memory usage as you'd expect.
Thanks
Martin
--
Martin J. Evans
Easysoft Limited
http://www.easysoft.com
