Which technique is most likely to improve query performance?
Options:
A.
Set the auto-sort property to maximum.
B.
Set the detail aggregation to 'Calculated' for measures.
C.
Avoid functions in filters.
D.
Add more joins between queries.
Answer:
C
Explanation:
Query Performance: Enhancing query performance involves various optimization techniques.
Avoid Functions in Filters: Using functions in filters can lead to slower query performance because functions often require additional computation and can prevent the database from using indexes efficiently.
Best Practices: It is recommended to simplify filters and avoid complex functions to ensure queries run faster.
Reference: IBM Cognos Analytics V11.1.x documentation suggests avoiding the use of functions in filters as a best practice for improving query performance.
Question 3
Which of the following can result in poor report performance?
Options:
A.
reports with filters
B.
models with outer joins and cross joins
C.
queries with database only processing
D.
an optimized metadata model
Answer:
B
Explanation:
Understanding Joins: Outer joins and cross joins often result in large intermediate result sets. This can slow down query performance due to the increased data processing required.
Outer Joins: These include rows that do not have matching keys in the joined tables, which means more data to process and potentially more I/O operations.
Cross Joins: These produce Cartesian products of the involved tables. If the tables are large, the resulting dataset can be enormous, leading to significant performance degradation.
Cognos Documentation: The IBM Cognos Analytics V11.1.x documentation advises optimizing join conditions and limiting the use of complex joins such as outer and cross joins to enhance performance.