Question 1
After a recent migration, a request has started to take significant time to complete. Upon a detailed investigation of the EXPLAIN plan, it is found that an accidental unconstrained product join on a very uniformly-distributed large table was the prime reason for the issue. The Administrator needs to use workload management to detect when this request is running.
Which criteria should the Administrator select for this issue?
CPU Skew is a metric that measures the uneven distribution of CPU usage across AMPs (Access Module Processors). In the case of an accidental unconstrained product join on a large, uniformly distributed table, certain AMPs may handle significantly more work than others, leading to high CPU Skew. This skew occurs because the product join results in an inefficient execution plan, where data from the large table is unnecessarily compared row-by-row with another table.
Option A (AWT Wait Time) refers to the time queries spend waiting for available AMP Worker Tasks, but it is not directly related to detecting the inefficiencies caused by product joins.
Option C (CPU Disk Ratio) measures the relationship between CPU usage and disk I/O. While it could indicate inefficiency, it doesn't directly pinpoint product join issues like CPU Skew does.
Option D (CPU Utilization) reflects overall CPU usage but doesn't indicate imbalance across AMPs, which is critical for detecting issues like product joins.


