Re: multiblock read count question

This is what Steve Adams says:

This is what the Ixora web tip on multiblock reads at http://www.ixora.com.au/tips/creation/multiblock.htm says on the matter ...

"Unfortunately, if you use buffered I/O the operating system will service multiblock reads as a series of small I/O operations anyway and the only benefit
from multiblock reads will be a small saving in CPU usage. In this case the multiblock read count should be approximately equal to the typical track length to take advantage of track buffering and no larger lest the optimizer be deceived."

The key word there is "buffered". If your filesystem is able to do direct I/O, and is configured to do so, then the large multiblock read principle applies. But, if your filesystem I/O is buffered, then there is very little to gain. Received on Wed Jun 20 2001 - 13:48:46 CDT