Oracle International Corporation

Nathan K Folkert

Sankar Subramanian

Abhinav Gupta

Andrew Witkowski

Srikanth Bellamkonda

Tolga Bozkaya

Thierry Cruanes

Bhaskar Ghosh

Lei Sheng

Techniques are described for parallelizing qualifying window functions without reliance on partitioning criteria specified in the command that includes the qualifying window functions. Because the techniques do not rely on partitioning criteria specified in the command, the techniques may be used on commands in which no partitioning criteria is specified. In general, the techniques involve partitioning the work of a qualified window function into ranges, and sharing precomputed aggregate values between computational elements to calculate the value for the window functions.

Parallel execution of window functions

Described herein are optimizations and execution strategies for spreadsheet extensions to SQL. The partitioning of data, as specified in a spreadsheet clause, provides a way to parallelize the computation of spreadsheet and to provide and improve scalability. Even if the partitioning is not explicitly specified in the spreadsheet clause, the database optimizer can automatically infer the partitioning in some cases. Efficient hash based access structures on relations can be used for symbolic array addressing, enabling fast computation of formulas. When rewriting SQL statements, formulas whose results are not referenced in outer blocks can be removed from the spreadsheet clause, thus removing unnecessary computations. The predicates from other query blocks can be moved inside query blocks with spreadsheets clauses, thus considerably reducing the amount of data to be processed. Conditions for validity of this transformation are given.

Compile-time optimizations of queries with SQL spreadsheet

Run-time optimizations of queries with SQL spreadsheet

A method and apparatus for densification of data is provided. A method and apparatus for including a construct for partitioning data within a DML statement is provided. The construct for partitioning data may not necessarily perform a densification of data, and the densification of data may not necessarily include a construct for partitioning data. In an embodiment, the syntax of an OUTER JOIN is extended to include a PARTITION BY construct that may be used for data densification.

DML statements for densifying data

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Nathan K Folkert