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Description

This error indicates that an attempt was made to create or alter a partitioned table where different partitions are defined to use different storage engines (handlers). MySQL, particularly in certain versions, does not permit mixing storage engines across partitions within a single table. It typically occurs during the execution of `CREATE TABLE` or `ALTER TABLE` statements involving partitioned tables.

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Error Message

The mix of handlers in the partitions is not allowed in this version of MySQL

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Known Causes

3 known causes

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Using Multiple Storage Engines

The SQL statement defines a partitioned table where individual partitions are explicitly assigned different storage engines (e.g., InnoDB for one partition and MyISAM for another).

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MySQL Version Limitation

The specific version of MySQL being used does not support the feature of mixing storage engines across partitions within a single partitioned table.

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Incorrect Partition Definition

The `CREATE TABLE` or `ALTER TABLE` statement for the partitioned table incorrectly specifies or implies different storage engines for its various partitions.

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Solutions

3 solutions available

1. Standardize Partition Engine to InnoDB medium

Convert all partitions to use the InnoDB storage engine to resolve handler conflicts.

1

Identify the table and its partitions, noting the current storage engines.

SHOW CREATE TABLE your_table_name;

2

If any partitions are using a different engine (e.g., MyISAM), you need to alter them to InnoDB. This involves recreating the table with all partitions using InnoDB. First, back up your data.

-- Example: Backup data from a specific partition
CREATE TABLE your_table_name_backup LIKE your_table_name;
INSERT INTO your_table_name_backup SELECT * FROM your_table_name PARTITION (partition_name);

3

Drop the existing table.

DROP TABLE your_table_name;

4

Recreate the table with all partitions explicitly defined to use InnoDB.

CREATE TABLE your_table_name (
    id INT NOT NULL,
    value VARCHAR(100),
    PRIMARY KEY (id, dt)
) PARTITION BY RANGE (TO_DAYS(dt)) (
    PARTITION p0 VALUES LESS THAN (TO_DAYS('2023-01-01')) ENGINE=InnoDB,
    PARTITION p1 VALUES LESS THAN (TO_DAYS('2024-01-01')) ENGINE=InnoDB,
    PARTITION p2 VALUES LESS THAN MAXVALUE ENGINE=InnoDB
);

5

Re-insert the backed-up data into the newly created table.

-- Example: Re-insert data from backup
INSERT INTO your_table_name SELECT * FROM your_table_name_backup;

2. Upgrade MySQL Version advanced

Update to a MySQL version that supports mixed partition handlers if your current version is older.

1

Check your current MySQL version.

SELECT VERSION();

2

Consult the MySQL documentation for your current version and the target version to confirm support for mixed partition handlers. Newer versions (e.g., MySQL 8.0+) generally have better support for this.

text: Refer to the official MySQL documentation for version-specific features and limitations.

3

Plan and execute a MySQL upgrade following best practices. This typically involves backing up your data, stopping the MySQL server, replacing the binaries, and restarting the server.

bash:
# Example for upgrading on Linux (commands may vary based on distribution)
# 1. Backup your data
# 2. Stop MySQL server
systemctl stop mysql
# 3. Update package lists and install new version (e.g., using apt or yum)
# 4. Restart MySQL server
systemctl start mysql
# 5. Run mysql_upgrade

4

After upgrading, verify that the table with mixed handlers can now be accessed or managed without the error.

text: No specific code, but re-run the operation that caused the error.

3. Consolidate Partitions with Single Engine medium

If upgrading is not feasible, manually convert each partition to the same storage engine.

1

Identify the table and all its partitions, noting the storage engine for each.

SHOW CREATE TABLE your_table_name;

2

Choose a single storage engine (preferably InnoDB) to be used for all partitions. This might involve migrating data between partitions if they use different engines.

text: Determine the primary engine to be used. InnoDB is recommended.

3

For each partition using a different engine, create a new partition with the desired engine and move the data. This is a multi-step process, often involving temporary tables.

-- Example: Move data from a MyISAM partition to a new InnoDB partition
-- 1. Add a new InnoDB partition
ALTER TABLE your_table_name ADD PARTITION (PARTITION p_new_engine VALUES LESS THAN (value) ENGINE=InnoDB);

-- 2. Temporarily disable foreign keys or unique checks if necessary
SET foreign_key_checks = 0;
SET unique_checks = 0;

-- 3. Move data from the old partition to the new one
INSERT INTO your_table_name PARTITION (p_new_engine) SELECT * FROM your_table_name PARTITION (p_old_engine);

-- 4. Verify data integrity
-- 5. Drop the old partition
ALTER TABLE your_table_name DROP PARTITION p_old_engine;

-- 6. Re-enable checks
SET foreign_key_checks = 1;
SET unique_checks = 1;

4

Repeat the process for all partitions until they all use the same storage engine.

text: Iterate through all partitions and apply the data migration steps.

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Related Errors

5 related errors

MySQL Error 1497: Mixed Partition Handlers Not Allowed