Predicate pushdown with late materialization in database query processing
AssigneeInternational Business Machines Corporation
InventorsRonald J. BARBER, Lin Qiao, Vijayshankar Raman, Richard S. Sidle
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Abstract
Embodiments of the present invention provide query processing for column stores by accumulating table record attributes during application of query plan operators on a table. The attributes and associated attribute values are compacted when said attribute values are to be consumed for an operation in the query plan, during the execution of the query plan. Table column record values are materialized late in query plan execution.
Claims14
A method of query processing over database tables laid out in column major order, comprising:
- accumulating table record attributes during application of query plan operators on a table;
- compacting attributes and associated attribute values when said attribute values are to be consumed for an operation in the query plan during the execution of the query plan, wherein compacting of an attribute comprises forming an array of values for that attribute that contains only entries for those rows that satisfy a specific set of query predicates and performing compaction on the array of values using a fixed list of processor instructions without using branch or conditional instructions;
- and
- materializing table column record values late in query plan execution.
A method of query processing over database tables laid out in column major order, comprising:
- accumulating table record attributes and compacting attributes and associated attribute values during execution of query plan operators on a table;
- wherein compacting of an attribute comprises forming an array of values for that attribute that contains only entries for those rows that satisfy a specific set of query predicates and performing compaction on the array of values using a fixed list of processor instructions without using branch or conditional instructions, wherein compacting is independent of branch flow;
- and
- materializing table column record values late in query plan execution.
Dependencies are inferred from the claim text.