Oracle Corporation
LOB query performance via automatic inference of locator-less LOB by value semantics

Abstract:

An approach for improving LOB query performance via automatic inference of locator-less LOB by value semantics in a relational database system is provided. A relational database management system (RDBMS) is implemented to perform operations on LOBs based on the semantics of a statement. During statement compilation, the RDBMS identifies inline LOB column(s) that are not required to be returned to a client. During execution, the identified column(s) are accessed via a shared buffer cache and fed to an operator for evaluation. For inline LOB column(s) that must be returned to the client, during execution, the inline LOB data is copied from the shared buffer cache to a temporary buffer area. Data in the temporary buffer area is fed to an operator for evaluation and is used to create a LOB locator for the inline LOB column(s) that must be returned to the client.