Re: Buffers and LRU.

"T.K" <gp@tf.de> wrote in message news:<bvrslu$67h$1@inews.gazeta.pl>... > Hello. > I'm beginner in use Informix. > Where can I find what are the main difference between > buffers and LRU queue. > > Thanks for your help > > T.K Its kind of like asking what is the difference between a car and the engine. :-) The LRU is the mechanism that Informix uses to quickly but still effectively get rid of pages that haven't been used recently from the buffers and replace them with new pages that it is reading from the disk. When you read something from the hard drive informix looks for a buffer that is in the clean (unchanged ) queue ( that way it doesn't have to write the buffer back to the hard-drive before it is used ) that hasn't been used recently ( in the front of the queue ). If not then it will use a clean a dirty page that hasn't been used recently. In 9.4 it looks like everytime that you use a page it gets put in the back of the line.