Solid state drives as a persistent cache for database systems

摘要

Disclosed herein are systems, methods, and computer readable storage media for a database system using solid state drives as a second level cache. A database system includes random access memory configured to operate as a first level cache, solid state disk drives configured to operate as a persistent second level cache, and hard disk drives configured to operate as disk storage. The database system also includes a cache manager configured to receive a request for a data page and determine whether the data page is in cache or disk storage. If the data page is on disk, or in the second level cache, it is copied to the first level cache. If copying the data page results in an eviction, the evicted data page is copied to the second level cache. At checkpoint, dirty pages stored in the second level cache are flushed in place in the second level cache.

主权项

1. A database system, comprising:
one or more random access memories configured to operate as a first level cache for the database system; one or more solid state drives configured to operate as a persistent second level cache for the database system; one or more hard disk drives configured to operate as disk storage for the database system; and a cache manager, implemented on one or more processors, configured to:
store a page directory in the second level cache;receive a request for a data page;determine where the requested data page is stored;ensure the requested data page is accessible from the first level cache, wherein to ensure comprises evicting a first level cache victim data page stored in the first level cache;determine whether the first level cache victim data page is from a random read;in response to determining the first level cache victim data page is from the random read, copy the first level cache victim data page from the first level cache to the second level cache;update one or more dirty pages stored in the second level cache in place at a checkpoint using the page directory when an image of the one or more dirty pages exists in the second level cache; anduse the page directory of the second level cache during a recovery process.