As of Oracle Database 11g it is possible to use a virtual column as partition key. In this post I do not want to discuss how it works and whether this is good or not… Instead, I would like to show you that the feature might lead to wrong results. First of all, I would […]
Invisible indexes are useful to temporarily hide an index from the query optimizer. In this post, instead of explaining what invisible indexes are, I would like to show whether the database engine uses invisible indexes to avoid false contention caused by unindexed foreign key. Let’s start by creating two test tables with a relation (foreign […]
Few days ago, in the post entitled Long Parses, I pointed out that stored outlines can be used to shorten the parse time by restricting the number of execution plans considered by the query optimizer. As of Oracle Database 11g, stored outlines are deprecated in favor of SQL plan baselines. Therefore, someone might think that […]