After checking the monitor tab in the Azure Synapse Studio environment, you realize that you can improve the performance of the run. Now, you decide to use bucketed tables to improve the performance. Which of the following are the recommended practices to consider while using bucketed tables? (Select all options that are applicable)

Answer options:

A.Avoid the use of SortMerge join whenever possible
B.Prefer the use of SortMerge join as much as you can
C.Never consider the most selective joins
D.Start with the most selective joins
E.Move joins that increase the number of rows after aggregations whenever possible.
F.The order of various types of joins matters when it comes to the resource consumption

Correct Answers: A, D, E and F 
While using bucketed tables, you need to deal with Merge join. A correctly pre-sorted and pre-partitioned dataset will skip the costly sort phase from a SortMerge join. 
The order of joins does matter, especially in more complex queries. Start with the most selective joins. You should also consider moving the joins that increase the number of rows after aggregations, whenever possible.
Option A is correct. While using bucketed tables, you should avoid the use of SortMerge join whenever possible.
Option B is incorrect. You should avoid using expensive SortMerge join while using bucketed tables.
Option C is incorrect. Instead of prefering the use of SortMerge join as much as you can, you should start with the most selective joins.
Option D is correct. You should start with the most selective joins to improve the performance.
Option E is correct. To increase the performance using bucketed tables, you should move joins that increase the number of rows after aggregations whenever possible
Option F is correct. The order of various types of joins matters when it comes to the resource consumption
Reference: 
To know more about Apache Spark Performance, please visit the below-given performance: 

https://docs.microsoft.com/en-us/azure/synapse-analytics/spark/apache-spark-performance