Analyzing query execution plans helps identify areas where statistics are outdated or missing, which can lead to poor query performance. Running Runstats updates these statistics, providing the query optimizer with accurate information for generating efficient execution plans. Reorganizing the database using the Reorg utility helps to defragment tables and indexes, improving data locality and access efficiency, thus further enhancing query performance. Adjusting buffer pool sizes and memory configurations may optimize memory usage but may not directly address the root cause of performance degradation related to outdated statistics or fragmented data. Disabling logging for tables and indexes is not a recommended practice as it compromises data integrity and recoverability. 

The EXPORT utility in DB2 handles large volumes of data by dividing it into manageable chunks. This approach prevents overwhelming system resources and allows for efficient processing. Additionally, it may utilize parallel processing to expedite the export process and can create temporary buffers to optimize data transfer. Moreover, data compression techniques may be employed to reduce the size of exported data files, further enhancing performance and storage efficiency. 

In a self-join, a table is joined with itself based on a common column, allowing comparisons between rows within the same table. This is useful for hierarchical data or when comparing related records. 

The output of a user-defined function in DB2 can be used as a column in SQL statements. This means that the result returned by the function can be treated as a regular column value and utilized in various SQL operations, including SELECT, INSERT, UPDATE, and DELETE statements. Utilizing user-defined functions in this manner enhances the flexibility and power of SQL queries, allowing developers to leverage custom logic within their database operations. 

DB2 installation offers various options including GUI for graphical interface guided installation, Console for command-line installation, Silent for unattended installation, and Custom for tailored installations. 

In DB2, user-defined functions are typically stored in Packages. Packages provide a way to group related functions and procedures together, making it easier to manage and deploy them within the database. 

The correct option is Option 3: Apply database changes. The ROLLFORWARD command in DB2 is used to apply database changes that were recorded in the transaction log files since the last backup was taken. It's essential for maintaining database integrity and consistency during recovery processes. 

The INSERT INTO statement in SQL is used to add new records or rows into a table. It allows you to specify the values for each field or column you want to insert into the table. 

Third Normal Form (3NF) 

The Communication Manager in DB2's architecture plays a crucial role in handling communication between clients and DB2 database instances, ensuring smooth interaction and efficient data transfer.