I propose to remove ap_old_write_filter from trunk. I recently noticed that buffer_output(), which is apparently intended to buffer data in a brigade to be passed down the output filter chain later by ap_old_write_filter, calls the ap_fwrite() macro to do so, which always flushes the data. So no data has been getting buffered. This has been the case for at least 10 years and back to Apache 2.0.x, which is as far back as I cared to check.
We could fix buffer_output() to save up the data in a brigade without flushing it, as was apparently intended, but would that break any module that has been (inadvertently) relying on buffer_output() to flush its data? Of the modules that use ap_rwrite and related APIs that end up calling buffer_output(), very few ever call ap_rflush. On the other hand, fixing the buffering might buy us some performance, as long as we're willing to fix any modules that get broken. Thoughts? Dan
