Query and exadata support for hybrid columnar compressed data

摘要

A method and apparatus is provided for optimizing queries received by a database system that relies on an intelligent data storage server to manage storage for the database system. Storing compression units in hybrid columnar format, the storage manager evaluates simple predicates and only returns data blocks containing rows that satisfy those predicates. The returned data blocks are not necessarily stored persistently on disk. That is, the storage manager is not limited to returning disc block images. The hybrid columnar format enables optimizations that provide better performance when processing typical database workloads including both fetching rows by identifier and performing table scans.

主权项

1. A method comprising:
for each set of rows of multiple sets of rows in a database table, a storage system storing on a non-volatile storage, said each set of rows in a separate compression unit of a plurality of compression units, wherein said each set of rows comprises columns of the database table that are stored in column major format within said separate compression unit, wherein said plurality of compression units are structures stored on the non-volatile storage for storing rows in said database table; the storage system receiving a request from a database server to return compression units that include a column having a value that satisfies one or more criteria specified in the request; in response to said request:
the storage system scanning the plurality of compression units for rows having column values that satisfy the one or more criteria;the storage system returning one or more compression units, wherein the one or more compression units have a column value that satisfies the one or more criteria; wherein the method is performed by one or more computing devices.