Fix SpamAssassin so that it can process multiple messages at once
Currently Mdaemon processes messages through MDSPAMD one at a time, even though there are settings in MD that suggest you can set how many are processed at once. On a medium to high volume server, processing one at a time causes the messages to pile up very quickly. Even with finely tuned SA rules, it still can cause a signficant backup. Often we see it taking over a minute to process a message through MDSPAMD (even though the MDSPAMD logs show that the messages are actually moving through within a few seconds). Logs show they are just going through one at a time though. So there are just too many messages and they are backing up.
The version of MDSpamD included with MDaemon 15.0.0 should improve the ability to process multiple messages at the same time.