SAP BASIS,HANA AND ORACLE DBA BLOGS

A BRIEF INTRO ON INDEX: Just like a book index helps us in finding the chapter and page number, an oracle index speeds up access time to the rows. Indexes are optional structures associated with tables. An index is also a schema object. We can drop an index without dropping the table it indexes. An index can be created explicitly or automatically. When we drop a table the corresponding indexes of the table are dropped. A unique index gets created when we create a unique key or primary key in a table definition.    The name of the index is the name of the constraint. Indexes can be unique or non-unique.  Unique indexes guarantee that no two rows of a table have duplicate values in the columns that define the index.  Non-unique indexes do not impose this restriction on the column values. The presences of more number of indexes on a table decreases the performance of DML statements, because Oracle must make changes to the indexes associated with the table For more c...

                        AWR REPORT ANALYSING                      BY ANAND GUPTA 1. Introduction 1.1. Purpose of Document AWR (Automatic Workload Repository) Reports are very handy during performance tuning of the database. These reports provide clear picture of database side activities. Various useful data is nicely documented in different sections in readable format. It becomes necessity to understand these reports for teams involved in activities like database tuning,performance/load testing or analyzing any performance issue. Purpose of the document is to enable the reader to understand basic AWR terminology and to use these details for understanding the database performance issues. 1.2. Scope This document describes how to utilize AWR reports to tune, ·       ...