MySQL Archive: Difference between revisions

Revision as of 14:40, 19 April 2009

Revision as of 14:41, 19 April 2009

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'''MySQL Archive''' is a storage engine for the [[MySQL]] [[relational database management system]]. Users can use this analytic storage engine to create a table that is “archive” only. Data cannot be deleted from this table, only added. The Archive engine uses a compression strategy based on the Zlib[[zlib]] library and it packs the rows using a bit header to represent nulls and removes all whitespace for character type fields. When completed, the row is inserted into the compression buffer and flushed to disk by an explicit flush table, a read, or the closing of the table.

The engine is not [[ACID]] compliant. Unlike [[OLTP]] engines, it uses a "stream" format to disk with no block boundaries. The head of the Archive file generated is a byte array representing the data format and contents of that file. In MySQL 5.1, a copy of the MySQL FRM file is stored in the header of each Archive file. The FRM file, which represents the definition of a table, allows an Archive file to be restored to a MySQL server if the Archive file is copied to the server.