Your handy scripts are as important as your Oracle DBA profile. We do have lot of scripts, documents, white papers and so on for our reference which are very vital throughout the career. The first source to find answers for any issue or an activity in the environment is your catalog directory where you must […]
Oracle DBA role is perceived to very hectic and demanding in terms of both energy and time. It is well understood that Oracle DBA’s will be mostly working in rotational shifts, overtime and few times are deprived of good sleep. For a moment, let us look at some other profiles/roles which demand similar working styles. […]
Most of us (Oracle DBAs) query GV$ views in RAC environment to gather information from multiple or all the nodes in the cluster. We call them as Global Dynamic Performance Views. Unlike V$ views, these will collate data from all the instances in RAC. We are going to look at this process in detail with […]
Oracle DBA’s often look at SQL_ID in the process of tuning an SQL statement that performs bad. Most of the DBA’s have a myth of “New SQL_ID of a SQL statement results in hard parsing generating new execution plan”. It is true that if the SQL statement is not found in the shared pool it […]
Tuning SQL statement is one of the major activities in performance tuning for every Oracle DBA. We would refer execution plan, SQL tuning advisor, SQL access advisor, Object statistics etc… to start identifying the issue with the SQL statement. In this process we often come across SQL_ID, HASH_VALUE and PLAN_HASH_VALUE details and use them for […]
Generating EXECUTION PLAN from explain plan is the best method of reading the plan that optimizer defined for executing a SQL statement in Oracle Database. There are multiple ways of generating such execution plans, one is by running EXPLAIN PLAN and other from V$SQL_PLAN. In this blog, I am going to cover in detail about […]
EXPLAIN PLAN is often used to generate execution plan of SQL statement or set of SQL statements. But we would always prefer to run EXPLAIN PLAN for each SQL statement and generate its execution plan using DBMS_XPLAN package and then pick up next SQL statement. But we can also run EXPLAIN PLAN for multiple SQL […]
SELECT statement in combination of ORDER BY or GROUP BY clause performs SORT operation which we all accept from the concepts of oracle architecture. Sort area in MEMORY is one of the areas of PGA in dedicated server architecture or will be part of SGA in shared server architecture. We all believe that sort in […]
After gaining theoretical knowledge from the Oracle documents or from Oracle university training every DBA will be under presumption that only DML operations in the database generates REDO segments. But practically it is not completely true. On few occasions you can identify that SELECT statements generates REDO segments in the instance. Next question you might […]
Understanding SCAN listener functionality has become tough to Oracle DBA’s because of multi layered listeners introduced in Oracle 11gR2 RAC. I have met an Oracle DBA with almost 4 years of experience and working actively on RAC setup for 1 year but lack of knowledge on how SCAN listener works. People often get confused as […]
