0 Replies Latest reply on Dec 4, 2012 2:50 PM by adhika

    Understanding Physical Reads

      Hello everyone,

      I'm trying to understand about physical reads statistics.

      we have a few statistics related to this.
      They are physical reads, physical reads cache, physical reads cache prefetch, physical reads direct, physical reads direct (lob), physical reads direct temporary tablespace, and physical reads prefetch warmup.

      From all those statistics, I thought that physical reads should be like the total of the rest of the other statistics.
      However, when I looked at the actual AWR report I collected from a production database here, it seems physical reads value is only similar to the value of physical reads cache + physical reads direct.

      I wonder about the rest of the statistics related to this physical reads, I thought that physical reads statistics is like the grand total of all those physical reads, however that doesn't seems to be the case. How do I interpret these statistcs?
      Appreciate if you can explain how these statistics can be used when understanding a database performance.

      Thank you,