![]() Redundant filters aren’t needed if you filter on a column that’s used in the join condition. The query returns the same result set, but Amazon Redshift is able to filter the join tables before the scan step and can then efficiently skip scanning blocks from those tables. Add predicates to filter tables that participate in joins, even if the predicates apply the same filters. ![]() Without this, the query execution engine must scan participating columns entirely. The query planner can then use row order to help determine which records match the criteria, so it can skip scanning large numbers of disk blocks.
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