Comments on: Propel and PHP Garbage collector

By: Ventzy

Ventzy — Fri, 08 Apr 2011 15:28:43 +0000

I had this issue when saving about 10000 objects. The process stopped at 650th object with exhausted 256 mb.

At the end of the loop I added:
$article->clearAllReferences(true);
unset($article); //don’t know is this actually needed

now I can create 10k objects without problems.

Additionally I called Propel::disableInstancePooling(); at start.

Propel 1.5 and php 5.3.

By: Fabian

Fabian — Wed, 09 Jan 2008 21:04:11 +0000

Hi Bert,
actually today I have read that his feature was dropped from 5.3 postponed to 6. Do you have any references?

By: Bert-Jan

Bert-Jan — Wed, 09 Jan 2008 08:56:01 +0000

The trouble with Propel’s circular references are supposed to be solved in the upcoming PHP 5.3, which has an improved garbage collector that can detect them and clean them up, at a slight performance penalty.
Initial testing showed that scripts were a little slower but used on average 30% less memory. The performance hit was still being worked on.

By: Bert-Jan

Bert-Jan — Fri, 05 Oct 2007 09:56:26 +0000

Maybe it’ll help if you don’t use a new Entry object every time, but build the Criteria directly and keep re-using the same Criteria object:

while (…) {
$crit->clear();
$crit->add(EntryPeer::ID, $row[0]);
$crit->add(EntryPeer::TITLE, utf8_encode($row[1]));
$crit->add(EntryPeer::BODY, utf8_encode($row[2]));
$crit->setDbName(EntryPeer::DATABASE_NAME);
EntryPeer::doInsert($crit);
}

By: Benjamin Bender

Benjamin Bender — Wed, 03 Oct 2007 20:07:56 +0000

Afaik, you are absolutly right – its an issue with propel by design. there are circular-references which (atm) will not caught by the garbage collector of php. In propel 1.3 its even “worser” caused by its instancepooling – but it can be disabled. And therefor its working quite nice for me, even with big datasets.

reference:
http://propel.phpdb.org/trac/ticket/379
http://propel.phpdb.org/trac/ticket/420

I’m using Propel 1.3 now and all the trouble is gone Also, the change from creole to pdo is such a huge step forward…

By: Sam C

Sam C — Tue, 02 Oct 2007 20:33:06 +0000

Memory leaks have never really been a big priority in PHP because the processes running the scripts are usually short lived. Mod_php pretty much throws away the interpreter every time a request is made. If you read the paper on scaling Flickr you’ll see that they originally started to write an ftp daemon in PHP and realized that it wasn’t going to work due to memory leaks.