large memory consumption when keeping a file open for while

[AnthonyAJohnson]

Using the C api, when parsing biggish files (~1GB) I experience huge memory bloat (~200mb) the longer I keep using the file, despite freeing individual items.

Closing the file seem to free all of the memory, so this isn't a leak, it's just using memory while it's open.

I was wondering if there was a way that lets you use less memory, maybe sacrificing speed/caching for it.