1*41fbaed0StronDelivering 1000 deferred messages over the loopback transport, 2*41fbaed0Stronoutbound concurrency 10. smtp-sink pipelining disabled. Machine is 3*41fbaed0StronP230, BSD/OS 3.1, 64MB memory. 4*41fbaed0Stron 5*41fbaed0Stronhashing is 16 directories per level 6*41fbaed0Stron 7*41fbaed0Stronflat deferred queue 8*41fbaed0Stron 9*41fbaed0Stron start: Sun Feb 21 16:42:37 EST 1999 10*41fbaed0Stron done: Feb 21 16:44:35 11*41fbaed0Stron time: 1:58 = 118 seconds 12*41fbaed0Stron 13*41fbaed0Stron start: Sun Feb 21 16:48:01 EST 1999 14*41fbaed0Stron done: Feb 21 16:49:51 15*41fbaed0Stron time: 1:50 = 110 seconds 16*41fbaed0Stron 17*41fbaed0Stronhashed deferred queue, depth=1 (16 directories) 18*41fbaed0Stron 19*41fbaed0Stron start: Sun Feb 21 17:29:36 EST 1999 20*41fbaed0Stron done: Feb 21 17:31:32 21*41fbaed0Stron time: 1:56 = 116 seconds 22*41fbaed0Stron 23*41fbaed0Stron start: Sun Feb 21 17:33:36 EST 1999 24*41fbaed0Stron done: Feb 21 17:35:24 25*41fbaed0Stron time: 1:48 = 108 seconds 26*41fbaed0Stron 27*41fbaed0Stron start: Sun Feb 21 17:37:08 EST 1999 28*41fbaed0Stron done: Feb 21 17:39:02 29*41fbaed0Stron time: 1:52 = 112 seconds 30*41fbaed0Stron 31*41fbaed0StronHashing does not slow down deliveries. 32*41fbaed0Stron 33*41fbaed0StronHowever the problem is scanning an empty deferred queue. On an idle 34*41fbaed0Stronmachine, it takes some 5 seconds to scan an empty depth=2 deferred 35*41fbaed0Stronqueue unless the blocks happen to be cached. During those 5 seconds 36*41fbaed0Stronthe queue manager will not pay attention to I/O from delivery 37*41fbaed0Stronagents, which is bad. 38