1Delivering 1000 deferred messages over the loopback transport, 2outbound concurrency 10. smtp-sink pipelining disabled. Machine is 3P230, BSD/OS 3.1, 64MB memory. 4 5hashing is 16 directories per level 6 7flat deferred queue 8 9 start: Sun Feb 21 16:42:37 EST 1999 10 done: Feb 21 16:44:35 11 time: 1:58 = 118 seconds 12 13 start: Sun Feb 21 16:48:01 EST 1999 14 done: Feb 21 16:49:51 15 time: 1:50 = 110 seconds 16 17hashed deferred queue, depth=1 (16 directories) 18 19 start: Sun Feb 21 17:29:36 EST 1999 20 done: Feb 21 17:31:32 21 time: 1:56 = 116 seconds 22 23 start: Sun Feb 21 17:33:36 EST 1999 24 done: Feb 21 17:35:24 25 time: 1:48 = 108 seconds 26 27 start: Sun Feb 21 17:37:08 EST 1999 28 done: Feb 21 17:39:02 29 time: 1:52 = 112 seconds 30 31Hashing does not slow down deliveries. 32 33However the problem is scanning an empty deferred queue. On an idle 34machine, it takes some 5 seconds to scan an empty depth=2 deferred 35queue unless the blocks happen to be cached. During those 5 seconds 36the queue manager will not pay attention to I/O from delivery 37agents, which is bad. 38