Rewrite constraints for database queries

A computer readable non-transitory storage medium storing instructions for:

• receiving a rewrite constraints specification identifying a subquery of a database query, the rewrite constraints specification identifying a subquery by specifying an alias of the subquery, wherein the alias corresponds to one or more intermediate results of a database query;
• identifying, from database queries, matching database queries that the rewrite constraints specification is applicable, comprising:
• matching the rewrite constraints specification with the database queries, and
• for each of the database queries:
• responsive to determining that the alias of the subquery identified in the rewrite constraints specification matches with at least an alias of a subquery of the database query, determining that the database query is one of the matching database queries;
• and
• for each matching database query:
• generating a statement to create a temporary table to store the intermediate result relation corresponding to the matching subquery,
• rewriting the matching database query by replacing the matching subquery with the temporary table, and
• executing the rewritten database query, wherein executing the rewritten database query comprises responsive to determining that the size of the temporary table is below a threshold, storing the temporary table in-memory.

A computer-implemented system for rewriting database queries based on rewrite constraints specification, the system comprising:

• a computer processor;
• and
• a computer-readable storage medium storing instructions thereon, the instructions for:
• receiving a rewrite constraints specification identifying a subquery of a database query, the rewrite constraints specification identifying a subquery by specifying an alias of the subquery, wherein the alias corresponds to one or more intermediate results of a database query;
• identifying, from database queries, matching database queries that the rewrite constraints specification is applicable, comprising:
• matching the rewrite constraints specification with the database queries, and
• for each of the database queries:
• responsive to determining that the alias of the subquery identified in the rewrite constraints specification matches with at least an alias of a subquery of the database query, determining that the database query is one of the matching database queries;
• and
• for each matching database query:
• generating a statement to create a temporary table to store the intermediate result relation corresponding to the matching subquery,
• rewriting the matching database query by replacing the matching subquery with the temporary table, and
• executing the rewritten database query, wherein executing the rewritten database query comprises responsive to determining that the size of the temporary table is below a threshold, storing the temporary table in-memory.