Doctrine with large datasets

Does anyone have experience using Doctrine with large datasets? I have a开发者_StackOverflow社区n import script that uses Doctrine and it uses way too much memory. The speed isn't a huge problem but the memory usage is. Does anyone have any tips for keeping Doctrine's memory usage down?

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In Doctrine 1.2 at least, freeing objects after use frees up memory, which is recommended for long-running scripts:

$my_object->free();

There's a few tips on improving performance at the end of the official guide:

http://www.doctrine-project.org/projects/orm/1.2/docs/manual/improving-performance/en