Hello everybody! I have a question about an article which was published in the May issue of Oracle magazine by Tom Kyte. http://www.oracle.com/technology/oramag/oracle/09-may/o39asktom.html
My problem is with the last example: He issues a 'select count(*) from emp' and compares the performance depending on some existing/non existing constraints. And there is also a materialized view involved, which is used to optimize the query in the second case. What I don't understand is that how can the optimizer use the mat view instead of the table? I mean the mat view might contain outdated data and when we are querying 'emp', we are curious about the live data, aren't we? What if I create the mat view, then I add more lines to the 'emp' table and then run the 'select count(*) from emp' query? If it goes to the mat view, it will return wrong row number for the 'emp' table. --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Oracle-DBA-OCP" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.co.in/group/Oracle-DBA-OCP?hl=en -~----------~----~----~----~------~----~------~--~---
