Oracle Wait Events

When writing posts on performance tuning I felt that there needs to be a my-version of description of Oracle Wait Events along with Access method and Process & Memory Architecture. Thus this series is to start the Oracle Wait events which are common in any Database Environment BUT has a lot of story. db file…

Index Range Scans

Optimizer chooses Index Range Scans for selective queries which have bounded as well as unbounded data. Thus for every predicate clause having >,>=,<,<= condition on an indexed column, Oracle optimizer would go for Index Range Scans unless fetching large amount of data or unselective query which favours FTS. Following are the situations where optimizer chooses…