Oracle Database Problem Solving and Troubleshooting Handbook

6. DDL Optimization Tips, Techniques, and Tricks

Prior to Oracle Database 11g, adding a column with a default value to a real-life production table was painful, particularly for a huge table where a substantial number of records would be enriched with the new column and physically updated with its default value. Such a table modification was far from being a simple operation. Fortunately, starting with Oracle Database 11g, a new optimization technique for improving the performance of data definition language (DDL) operations has been implemented. Adding a non-null column with a default value to an existing table can be done almost instantaneously. This chapter explains how Oracle has internally transformed such a painful table modification into ...