I’ve tried the same thing using Python 3.2 since that uses newer versions of Lxml and LibXml and the same problem exists. In fact, I think I’ve traced the problem to lxml.etree.XPath when it’s compiling an xpath expression. Even disabling smart_strings has no effect.

 

I’ve also read http://lxml.de/FAQ.html#id1 but I don’t think any of that applies as I’m not running the threads concurrently, I’m just using a thread (in this example anyway) and it’s keeping something in memory.

 

I’ve also been looking at the error log that lxml seems to store, but I don’t think that applies since there should be no errors in this case (and it only seems to store ~100 messages but in my example the memory just keeps on growing)

 

Could anyone confirm if this is really a bug?

Thanks,