On Sunday 04 October 2009, Paul Querna wrote: > > URL: http://svn.apache.org/viewvc?rev=821477&view=rev > > Log: > > Make sure to not destroy bucket brigades that have been created > > by earlier filters. Otherwise the pool cleanups would be removed > > causing potential memory leaks later on. > > I am not sure these changes make sense. The 'traditional' API view > says that brigades passed down the output fitler chain should be > destroyed, not cleared -- please see the thread started with this > message: > <http://mail-archives.apache.org/mod_mbox/httpd-dev/200504.mbox/%3C > 9ccfb16df2220fc31c836bb7cd640...@ricilake.net%3e> >
This is at odds with the documentation at http://httpd.apache.org/docs/trunk/developer/output-filters.html , in particular with rules 6 and 9 at the end. If output filters reuse brigades, the core must not destroy them. I just noticed that include/util_filter.h still says "The caller relinquishes ownership of the brigade" for ap_pass_brigade(). Either output-filters.html or util_filter.h must be changed. In my opinion, it is much better to not destroy the brigades and reuse them instead of creating a new brigade on every filter invocation. Otherwise there is huge memory usage for streaming content. The thread you have pointed out also has a suggested patch for the docs in util_filter.h: http://mail-archives.apache.org/mod_mbox/httpd- dev/200504.mbox/<20050426102834.ge16...@redhat.com> It is not clear from the thread why it wasn't applied.
