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Amazon Redshift: A Columnar Database SQL and Architecture by David Cook, Tom Coffing

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Chapter 6 - Explain

“Fall seven times, stand up eight.”

- Japanese Proverb

Three Ways to Run an EXPLAIN

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When you run an EXPLAIN, you are seeing the plan passed to the slices by the optimizer on the Leader Node. There are three ways to see an EXPLAIN. You can merely type the word EXPLAIN in front of any SQL. You can also hit F6 (Function Key 6), or you can click on the magnifying glass in Nexus. The EXPLAIN shows the plan, but does NOT run the actual query. Once you see the costs of the EXPLAIN, you can decide whether or not to run the query.

EXPLAIN – Steps, Segments and Streams

Step - Each individual step is an individual operation in the explain ...

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