If you had many db file scattered reads above and now find some entries with segment type = table in here, these may need some|more|better|other indices. Use Statspack or Oracle Enterprise Manager Diagnostics Pack to find out more.

Other things that may help to avoid some of the db file * read wait events are:

  • Tune the SQL statements used by your applications and users (most important!)
  • Re-Analyze the schema to help the optimizer with accurate data e.g. with dbms_stats
  • Stripe objects over multiple disk volumes
  • Pin frequently used objects
  • Increase the buffer caches