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Description

MySQL Error 1492, 'For %s partitions each partition must be defined', indicates that a table intended for partitioning lacks the necessary explicit definitions for its partitions. This error occurs when creating or altering a table using a `PARTITION BY` clause without specifying the individual `PARTITION` clauses that define the boundaries or values for each segment. MySQL requires precise definitions to properly manage data distribution across partitions.

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Error Message

For %s partitions each partition must be defined

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Known Causes

4 known causes

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Missing Partition Definitions

The `PARTITION BY` clause was specified for the table, but the subsequent `PARTITION` clauses, which explicitly define each partition's boundaries or values, were entirely omitted.

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Incomplete Partition Specification

While some partitions might have been defined, not all expected or required partitions have their specific definitions (e.g., `VALUES LESS THAN`, `VALUES IN`) explicitly stated in the `CREATE TABLE` or `ALTER TABLE` statement.

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Incorrect Partitioning Syntax

The syntax used within the `PARTITION BY` and `PARTITION` clauses contains errors, making it impossible for MySQL to parse and understand the intended partition structure.

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Mismatched Partitioning Scheme Usage

Attempting to use a partitioning type (e.g., `RANGE` or `LIST`) that requires explicit boundary or value definitions for each partition, but failing to provide these necessary specifications.

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Solutions

4 solutions available

1. Correct Partitioning Syntax easy

Ensure all partitions are explicitly defined when using `PARTITION BY`.

1

Review your `CREATE TABLE` or `ALTER TABLE` statement that defines partitioning.

Example of incorrect syntax:
CREATE TABLE my_table (
    id INT PRIMARY KEY
) PARTITION BY RANGE (id) (PARTITION p0 VALUES LESS THAN (10));

Example of correct syntax:
CREATE TABLE my_table (
    id INT PRIMARY KEY
) PARTITION BY RANGE (id) (
    PARTITION p0 VALUES LESS THAN (10),
    PARTITION p1 VALUES LESS THAN (20)
);

2

For each partition defined in the `PARTITION BY` clause, provide a corresponding `PARTITION name VALUES condition` statement.

For example, if you intend to have 3 partitions, you must define all three:
ALTER TABLE my_table PARTITION BY RANGE(id) (
    PARTITION p0 VALUES LESS THAN (10),
    PARTITION p1 VALUES LESS THAN (20),
    PARTITION p2 VALUES LESS THAN MAXVALUE
);

2. Use `MAXVALUE` for the Last Partition easy

When using range partitioning, always define the last partition with `MAXVALUE` to catch all remaining values.

1

Examine your `PARTITION BY RANGE` clause.

If your last partition is defined with a specific value like `VALUES LESS THAN (100)`, and you have more than one partition, you'll encounter this error if not all partitions are explicitly defined.

2

Ensure the final partition uses `MAXVALUE` to cover all subsequent values.

CREATE TABLE sales (
    sale_date DATE,
    amount DECIMAL(10,2)
) PARTITION BY RANGE (YEAR(sale_date)) (
    PARTITION p2021 VALUES LESS THAN (2022),
    PARTITION p2022 VALUES LESS THAN (2023),
    PARTITION p2023 VALUES LESS THAN (2024),
    PARTITION p_future VALUES LESS THAN MAXVALUE
);

3. Recreate Table with Correct Partitioning medium

If the existing table has incorrect partitioning, recreate it with the proper definitions.

1

Create a new table with the correct partitioning scheme.

CREATE TABLE my_table_new (
    id INT PRIMARY KEY,
    data VARCHAR(255)
) PARTITION BY HASH(id) PARTITIONS 4;

2

Copy data from the old table to the new table.

INSERT INTO my_table_new (id, data)
SELECT id, data FROM my_table;

3

Rename the tables to replace the old one with the new partitioned table.

RENAME TABLE my_table TO my_table_old, my_table_new TO my_table;

4

Drop the old table once you confirm data integrity.

DROP TABLE my_table_old;

4. Check Partition Function and Number of Partitions medium

Verify that the partition function aligns with the number of explicitly defined partitions.

1

Examine the `PARTITION BY` clause and count the number of defined partitions.

For example, if you have `PARTITION BY LIST COLUMNS(status)` and only define one partition like `PARTITION p_active VALUES IN ('active')`, but expect more, you'll get this error.

2

Ensure that the number of partitions declared in the `PARTITION BY` clause (e.g., `PARTITIONS 4` for HASH or KEY) matches the number of explicitly defined partitions for RANGE, LIST, or COLUMNS partitioning.

If using HASH or KEY partitioning, the `PARTITIONS N` clause automatically creates N partitions. If you then try to manually define partitions, it might conflict.

Correct for HASH:
CREATE TABLE my_table (
    id INT
) PARTITION BY HASH(id) PARTITIONS 4;

3

For RANGE, LIST, or COLUMNS partitioning, explicitly define all partitions.

CREATE TABLE my_table (
    id INT
) PARTITION BY RANGE(id) (
    PARTITION p0 VALUES LESS THAN (10),
    PARTITION p1 VALUES LESS THAN (20),
    PARTITION p2 VALUES LESS THAN MAXVALUE
);

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Related Errors

5 related errors

MySQL Error 1492: Missing Partition Definitions