STORING AND QUERYING RELATIONAL DATA IN COMPRESSED STORAGE FORMAT

摘要

A method and mechanism is disclosed for implementing storage and retrieval o f data in a computing system. Data compression is performed on stored data by reducing or eliminating duplicated values in a database block. Rather than writing the duplicated data values to the data storage unit, the on-disk dat a is configured to reference a copy of each duplicated data value stored in a symbol table. A method and mechanism of improving performance of database query language statements is also disclosed. Information describing data duplication within a data block is maintained. In one embodiment, the data duplication information is used to reduce number of predicate evaluations on data in the data block when a database query language statement is received against the data in the data block. In another embodiment, the data duplication information is used to reduce amount of data accessed by a database query language statement.