Ideal Distribution Style for Fact Table

Answer - B.

The AWS Documentation mentions the following.

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Choose the Best Distribution Style.

When you execute a query, the query optimizer redistributes the rows to the compute nodes as needed to perform any joins and aggregations.

The goal in selecting a table distribution style is to minimize the impact of the redistribution step by locating the data where it needs to be before the query is executed.

Distribute the fact table and one dimension table on their common columns.

Your fact table can have only one distribution key.

Any tables that join on another key aren't collocated with the fact table.

Choose one dimension to collocate based on how frequently it is joined and the size of the joining rows.

Designate both the dimension table's primary key and the fact table's corresponding foreign key as the DISTKEY.

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Since this is clearly mentioned in the AWS Documentation, all other options are invalid.

For more information on choosing the best distribution style, please refer to the below URL.

https://docs.aws.amazon.com/redshift/latest/dg/c_best-practices-best-dist-key.html

When it comes to optimizing join performance in Redshift, selecting the appropriate distribution style is crucial. In this scenario, since the company is dealing with large fact and dimension tables, it is important to choose the ideal distribution style for the fact table to ensure efficient query performance.

Option A: Even distribution style would distribute the data evenly across all nodes in the Redshift cluster. This may not be the best option since it can result in inefficient join performance as it requires data to be redistributed across nodes for join queries.

Option B: Key distribution style distributes the rows of the fact table according to the values in one column of the table, called the distribution key. This distribution style is suitable if the join queries frequently use the distribution key column in join conditions. However, it may not be the best option if the distribution key column is not frequently used in join queries.

Option C: Primary distribution style distributes the rows of the fact table according to the values of the primary key. This distribution style is useful if the primary key column is frequently used in join queries. However, it may not be the best option if the primary key column is not frequently used in join queries.

Option D: Choosing all distribution styles means that Redshift will automatically select the optimal distribution style based on the characteristics of the table being loaded. This can be a good option, but it also means that the distribution style may change as the table grows and can result in inefficient query performance.

Considering the above options, the best distribution style for the fact table would be option B: Key distribution style. This is because it allows data to be distributed based on the values in the column most frequently used in join queries. However, it is important to note that the selection of the distribution style should also consider the data size, the number of nodes in the cluster, and the query pattern to optimize the performance.