DB2 10 for z/OS Database Administrator — Question 11

The DBA has observed that queries executed against SALES table have poor performance. SALES is a compressed table and recently there have been a lot of rows inserted and modified in that table. The DBA has detected that lower performance may be the result of sub-optimal compression dictionary for that table.
Which of the following commands should be used to resolve the problem without preventing users from changing data in the SALES table

Answer options

• A. REORG TABLE sales INPLACE RESETDICTIONARY
• B. REORG TABLE sales INPLACE REBUILDDICTIONARY
• C. REORG TABLE sales ALLOW WRITE ACCESS RESETDICTIONARY
• D. REORG TABLE sales ALLOW WRITE ACCESS REBUILDDICTIONARY

Correct answer: C

Explanation

The correct answer is C, as the REORG TABLE command with ALLOW WRITE ACCESS and RESETDICTIONARY allows the DBA to reset the compression dictionary while keeping the table accessible for write operations. Option A and B do not permit write access, making them unsuitable. Option D, while allowing write access, does not reset the dictionary, which is necessary to address the performance issue.