The Big SQL engine analyzes incoming queries.It separates portions to execute at the server versus the portions to be executed by the cluster. It rewrites queries if
necessary for improved performance; determines the appropriate storage handle for data; produces the execution plan and executes and coordinates the query.
IBM architected Big SQL with the goal that existing queries should run with no or few modifications and that queries should be executed as efficiently as the chosen storage mechanisms allow. And rather than build a separate query execution infrastructure they made Big SQL rely much on Hive, so much of the data manipulation language, the data definition language syntax, and the general concepts of Big SQL are similar to Hive. And Big SQL shares catalogues with Hive via the Hive metastore.Hence each can query each other’s tables.
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