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Description

This error occurs when an `ALTER TABLE ... REORGANIZE PARTITION` statement attempts to change the total number of partitions or redefine the table's fundamental partitioning scheme. MySQL's `REORGANIZE PARTITION` clause is specifically designed to modify the data distribution within *existing* partitions, not to alter their count or the partitioning method.

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Error Message

REORGANIZE PARTITION can only be used to reorganize partitions not to change their numbers

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Known Causes

3 known causes

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Changing Partition Count

This error is triggered when the `REORGANIZE PARTITION` clause is used in a way that would inherently increase or decrease the total number of partitions for the table.

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Altering Partitioning Scheme

Using `REORGANIZE PARTITION` to change the underlying partitioning type (e.g., from HASH to RANGE) or the partitioning expression itself will result in this error.

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Misuse with Other Operations

The statement might be attempting to combine `REORGANIZE PARTITION` with syntax intended for adding, dropping, or merging partitions in a way that implicitly changes partition numbers.

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Solutions

3 solutions available

1. Recreate Partitions with Desired Configuration medium

Drop and recreate partitions with the correct number and definitions.

1

Identify the current partitioning scheme of your table using `SHOW CREATE TABLE`.

SHOW CREATE TABLE your_table_name;

2

Back up the data in your table. This is crucial before making structural changes.

CREATE TABLE your_table_name_backup LIKE your_table_name;
INSERT INTO your_table_name_backup SELECT * FROM your_table_name;

3

Drop the existing partitions. Be extremely cautious with this step.

ALTER TABLE your_table_name DROP PARTITION partition_name1, partition_name2, ...;

4

Recreate the partitions with the correct number and definitions using `ALTER TABLE ... PARTITION BY ...`.

ALTER TABLE your_table_name PARTITION BY RANGE (column_name) (
    PARTITION p0 VALUES LESS THAN (100),
    PARTITION p1 VALUES LESS THAN (200),
    PARTITION p2 VALUES LESS THAN MAXVALUE
);

5

If you dropped all partitions, you might need to re-insert the data from your backup.

INSERT INTO your_table_name SELECT * FROM your_table_name_backup;

6

Verify the new partitioning scheme and data integrity.

SHOW CREATE TABLE your_table_name;
SELECT COUNT(*) FROM your_table_name;

2. Add or Remove Individual Partitions easy

Use `ADD PARTITION` and `DROP PARTITION` to adjust the partition count.

1

Determine if you need to add or remove partitions based on your requirements. For example, if you need more partitions, you'll add them. If you have too many, you'll drop them.

2

To add a partition, use `ALTER TABLE ... ADD PARTITION`.

ALTER TABLE your_table_name ADD PARTITION (
    PARTITION p3 VALUES LESS THAN (300)
);

3

To remove a partition, use `ALTER TABLE ... DROP PARTITION`.

ALTER TABLE your_table_name DROP PARTITION p1;

4

After adding or removing partitions, you may need to reorganize data within the table if the partition strategy requires it (e.g., moving data to a newly added partition). This might involve manual data movement or a bulk load operation if the data doesn't automatically fall into the new partitions.

5

Verify the changes to the partitioning scheme.

SHOW CREATE TABLE your_table_name;

3. Use `REORGANIZE PARTITION` for Data Rebalancing within Existing Partitions medium

Use `REORGANIZE PARTITION` to redistribute data within the *existing* number of partitions, not to change their count.

1

Understand that `REORGANIZE PARTITION` is for optimizing data distribution *within* the current partition structure, not for changing the number of partitions. This command can be used to merge adjacent partitions or split a partition.

2

To split a partition, you'll need to provide the new partition definition. This effectively changes the boundary of an existing partition.

ALTER TABLE your_table_name REORGANIZE PARTITION p1 INTO (
    PARTITION p1_new VALUES LESS THAN (150),
    PARTITION p1_old VALUES LESS THAN (200)
);

3

To merge adjacent partitions, you'll redefine the boundary of the earlier partition to encompass the later one.

ALTER TABLE your_table_name REORGANIZE PARTITION p0, p1 INTO (
    PARTITION p0_merged VALUES LESS THAN (200)
);

4

Ensure that the new partition definitions are valid and contiguous with neighboring partitions.

5