10 Apr, 2007
- What is a deadlock and what is a live lock? How will you go about resolving deadlocks?
- Deadlock is a situation when two processes, each having a lock on one piece of data, attempt to acquire a lock on the other’s piece. Each process would wait indefinitely for the other to release the lock, unless one of the user processes is terminated. SQL Server detects deadlocks and terminates one user’s process. A livelock is one, where a request for an exclusive lock is repeatedly denied because a series of overlapping shared locks keeps interfering. SQL Server detects the situation after four denials and refuses further shared locks. A livelock also occurs when read transactions monopolize a table or page, forcing a write transaction to wait indefinitely. Check out SET DEADLOCK_PRIORITY and “Minimizing Deadlocks” in SQL Server books online.
10 Apr, 2007
- What’s the maximum size of a row?
- 8060 bytes. Don’t be surprised with questions like ‘what is the maximum number of columns per table’. 1024 columns per table. Check out SQL Server books online for the page titled: “Maximum Capacity Specifications”. Explain Active/Active and Active/Passive cluster configurations Hopefully you have experience setting up cluster servers. But if you don’t, at least be familiar with the way clustering works and the two clusterning configurations Active/Active and Active/Passive. SQL Server books online has enough information on this topic and there is a good white paper available on Microsoft site. Explain the architecture of SQL Server This is a very important question and you better be able to answer it if consider yourself a DBA. SQL Server books online is the best place to read about SQL Server architecture. Read up the chapter dedicated to SQL Server Architecture.
10 Apr, 2007
- What is normalization? Explain different levels of normalization?
- Check out the article Q100139 from Microsoft knowledge base and of course, there’s much more information available in the net. It’ll be a good idea to get a hold of any RDBMS fundamentals text book, especially the one by C. J. Date. Most of the times, it will be okay if you can explain till third normal form.
- What is denormalization and when would you go for it?
- As the name indicates, denormalization is the reverse process of normalization. It’s the controlled introduction of redundancy in to the database design. It helps improve the query performance as the number of joins could be reduced.
10 Apr, 2007
- What is JServer and what is it used for? Oracle JServer Option is a Java Virtual Machine (Java VM) which runs within the Oracle database server’s address space. Oracle also provides a JServer Accelerator to compile Java code natively. This speeds up the execution of Java code by eliminating interpreter overhead.
- How does one install the Oracle JServer Option?Follow these steps to activate the Oracle JServer/ JVM option:
- Make sure your database is started with large java_pool_size (>20M) and shared_pool_size (>50M) INIT.ORA parameter values.
- Run the $ORACLE_HOME/javavm/install/initjvm.sql script from SYS AS SYSDBA to install the Oracle JServer Option on a database.
10 Apr, 2007
- How does one deploy SQLJ programs? Use the sqlj compiler to compile your *.sqlj files to *.java and *.ser files. The *.ser files contain vendor specific database code. Thereafter one invokes the javac compiler to compile the .java files to *.class files. The *.class and *.ser files needs to be deployed.
- What is JDeveloper and what is it used for? JDeveloper is the Oracle IDE (Integrated Development Environment) for developing SQLJ and JDBC programs, applets, stored procedures, EJB’s, JSP’s etc.
