CACHING DATA BETWEEN A DATABASE SERVER AND A STORAGE SYSTEM

摘要

Techniques are provided for using an intermediate cache between the shared cache of an application and the non-volatile storage of a storage system. The application may be any type of application that uses a storage system to persistently store data. The intermediate cache may be local to the machine upon which the application is executing, or may be implemented within the storage system. In one embodiment where the application is a database server, the database system includes both a DB server-side intermediate cache, and a storage-side intermediate cache. The caching policies used to populate the intermediate cache are intelligent, taking into account factors that may include which object an item belongs to, the item type of the item, a characteristic of the item, or the type of operation in which the item is involved.

主权项

1. A method comprising:
at a storage system, responding to input/output (I/O) requests from one or more database servers by retrieving requested disk blocks from one or more storage devices within the storage system, the requested disk blocks storing data representative of database objects with respect to which the one or more database servers perform database operations; for a given disk block of the requested disk blocks, the storage system determining whether to cache the given disk block in an intermediate cache within the storage system, the determining being based at least partially upon one or more of:
whether a given database object, for which the given disk block stores data, is associated with a particular designation;whether the given disk block is of an index block type;whether the given disk block is of a data block type;whether the given disk block is of an undo block type;whether the given disk block is encrypted;whether the given disk block is a secondary copy of a mirrored item; orwhether the given disk block is involved in a table scan operation; when a particular disk block is cached in the intermediate cache, the storage system responding to a particular I/O request for the particular disk block by retrieving the particular disk block from the intermediate cache; wherein the method is performed by one or more computing devices.