Kevin Brown <[EMAIL PROTECTED]> writes: > In the case of pure random reads, you'll end up having to wait an > average of half of a rotation before beginning the read.
You're assuming the conclusion. The above is true if the disk is handed one request at a time by a kernel that doesn't have any low-level timing information. If there are multiple random requests on the same track, the drive has an opportunity to do better than that --- if it's got all the requests in hand. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq