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HailDB is a Storage Engine plugin that uses the HailDB library
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(`http://www.haildb.com <http://www.haildb.com>`_) for storage. The HailDB
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library is based off the innodb_plugin. By having HailDB as a separate shared
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library, you are able to upgrade HailDB with new features or bug fixes
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without having to update your whole database server.
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HailDB is intended to replace the inbuilt innobase plugin.
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Table definitions are stored inside the HailDB data files and modified
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inside the same transaction as the DDL operation. You can never get
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out of sync between tables in HailDB and the table definition.
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The HailDB storage engine code is much smaller and cleaner than the
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* Smaller and faster auto_increment implementation
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Without the legacy of auto_increment locking for MySQL replication,
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we are able to use a simple global atomic variable for each table.
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* Direct access to the HailDB DATA_DICTIONARY
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You can directly query the underlying (internal) data dictionary
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* Does not yet support FOREIGN KEYs
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* No semi-consistent read
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* No descending indexes
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* Some DATA_DICTIONARY views have not yet been ported over.
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* Tables without an explicit PRIMARY KEY get a hidden 64bit auto_increment
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primary key instead of the internal ROW_ID as a primary key.
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HailDB supports: REPEATABLE READ, READ COMMITTED, SERIALIZABLE and READ
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UNCOMMITTED isolation levels.
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HailDB can store the rows for a table in one of a few ways. This can be specified as an option to CREATE TABLE (example below).::
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pk bigint auto_increment primary key,
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) ROW_FORMAT='COMPRESSED' ENGINE=InnoDB;
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Oldest row format. It was the default prior to MySQL 5.0.3. You probably
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no longer want to use this row format.
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Default since MySQL 5.0.3. It uses less space than the REDUNDANT row format
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for variable length filends and nulls.
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(Requires Barracuda file format or higher). TEXT and BLOB fields are stored
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separately to the rest of the row.
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(Requires Barracuda file format or higher). Similar to Dynamic, but database
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pages are compressed. This trades off slightly increased CPU usage for smaller
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removed
plugin/haildb/docs/index.rst
