A company is planning on using Amazon Redshift as part of their ETL ecosystem. They want to ensure that they use the recommended practices for using AWS Redshift for the various process. Which of the following are recommended from AWS? Choose 2 answers from the options given below

Answer options:

A.For various ETL processes which use AWS Redshift commits, use transaction handling
B.Extract Large results sets from Redshift using the select query
C.Extract Large results sets from Redshift using the UNLOAD statement
D.Copy data into Redshift using Insert queries

Answer – A and C
The AWS Documentation mentions the following
ETL transformation logic often spans multiple steps. Because commits in Amazon Redshift are expensive, if each ETL step performs a commit, multiple concurrent ETL processes can take a long time to execute.
To minimize the number of commits in a process, the steps in an ETL script should be surrounded by a BEGIN…END statement so that a single commit is performed only after all the transformation logic
Use UNLOAD to extract large results sets directly to S3. After it’s in S3, the data can be shared with multiple downstream systems. By default, UNLOAD writes data in parallel to multiple files according to the number of slices in the cluster. All the compute nodes participate to quickly offload the data into S3.
The other options are invalid since for large data sets use the UNLOAD command and for copying data use the COPY command
For more information on high performance for Redshift, please visit the url
https://aws.amazon.com/blogs/big-data/top-8-best-practices-for-high-performance-etl-processing-using-amazon-redshift/