Lazy Write-Back??

• Quoting Lawrence James to All dated 10-28-94 ***
  > If you want a repeatable measure of physical reads you need to flush
  > any possible existing blocks. I do it by selecting from a really large
  > table unrelated to my test. That fills the buffer up with that table and I
  > know that none of my test tables are in it.
  

Bzzt! This won't always do it -- the block buffering algorithm will detect when a very large query will overflow -all- the block buffers, and does not use a pure LRU algorithm -- in other words, you aren't guaranteed that the buffers have all been replaced or invalidated. (You can verify this using SQL*DBA.) Received on Wed Nov 02 1994 - 17:38:36 CET