Tom Lane wrote: > Bruno Wolff III <[EMAIL PROTECTED]> writes: > > Are you sure about that? That would probably be the normal case, but are > > you promised that the hardware will write all of the sectors of a block > > in order? > > I don't think you can possibly assume that. If the block crosses a > cylinder boundary then it's certainly an unsafe assumption, and even > within a cylinder (no seek required) I'm pretty sure that disk drives > have understood "write the next sector that passes under the heads" > for decades.
SCSI tagged queueing certainly allows 512-byte blocks to be reordered during writes. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
