Safari Books Online is a digital library providing on-demand subscription access to thousands of learning resources.
- Create BookmarkCreate Bookmark
- Create Note or TagCreate Note or Tag
- DownloadDownload
- PrintPrint
Chapter 29. Storage Engines > The MEMORY Engine
29.5. The MEMORY Engine
The MEMORY storage engine manages tables that have the following characteristics:
Each MEMORY table is represented on disk by an .frm format file in the database directory. Table data and indexes are stored in memory.
In-memory storage results in very fast performance.
MEMORY table contents do not survive a restart of the server. The table structure itself survives, but the table contains zero data rows after a restart.
MEMORY tables use up memory (obviously), so they should not be used for large tables.
MySQL manages query contention for MEMORY tables using table-level locking. Deadlock cannot occur.
MEMORY tables cannot contain TEXT or BLOB columns.
