Driving massive scale out through rewrites of analytical functions

A method, comprising:

• a DBMS (database management system) rewriting a particular query to generate a rewritten query, wherein the particular query specifies a window function operator, a particular input to the window function operator, and an analytical function, wherein rewriting the particular query includes:
• assigning the particular input to an intermediate relation;
• replacing the window function operator with a pure aggregation operator and assigning to the pure aggregation operator:
• an aggregate function corresponding to the analytical function, and
• the intermediate relation;
• placing a Cartesian product operator that operates on the intermediate relation and on an output of the pure aggregation operator;
• and
• said DBMS executing said rewritten query.

One or more non-transitory computer-readable storage medium storing instructions that, when executed by one or more processors, cause the one or more processors to perform functions comprising:

• a DBMS (database management system) rewriting a particular query to generate a rewritten query, wherein the particular query specifies a window function operator, a particular input to the window function operator, and an analytical function, wherein rewriting the particular query includes:
• assigning the particular input to an intermediate relation;
• replacing the window function operator with a replacement operator, and assigning to the replacement operator:
• an aggregate function corresponding to the analytical function, and
• the intermediate relation;
• placing a join operator that joins the intermediate relation with an output of the replacement operator;
• said DBMS executing said rewritten query.

A method, comprising:

• a DBMS (database management system) rewriting a particular query to generate a rewritten query, wherein the particular query specifies a window function operator, a particular input to the window function operator, and an analytical function, wherein rewriting the particular query includes:
• assigning the particular input to an intermediate relation;
• replacing the window function operator with a replacement operator, and assigning to the replacement operator:
• an aggregate function corresponding to the analytical function, and the intermediate relation;
• placing a join operator that joins the intermediate relation with an output of the replacement operator;
• said DBMS executing said rewritten query.