<p>The error occurs when an ALTER TABLE ... ADD PARTITION statement specifies a number of subpartitions that does not match the table's existing partitioning scheme.</p>
<p>MySQL Error 1513: ER_ADD_PARTITION_SUBPART_ERROR appears when ALTER TABLE ... ADD PARTITION provides a mismatched subpartition count. Align the subpartition count with the original PARTITION BY clause or omit SUBPARTITION definitions to fix the issue.</p>
Trying to Add partition(s) with wrong number of
MySQL raises ER_ADD_PARTITION_SUBPART_ERROR when an ALTER TABLE ... ADD PARTITION command tries to add partitions that define a different number of subpartitions than the table currently uses. The engine enforces symmetry across all partitions.
For example, a table partitioned by RANGE with two SUBPARTITIONS each must keep that two-subpartition layout for every new partition. Supplying three subpartitions triggers the error.
The error occurs during schema-level operations, not at query time. It mainly appears on MySQL 5.1+ because earlier versions lacked composite partitioning.
Developers usually encounter it while extending time-series tables or restructuring sharding keys.
Leaving the table unpartitioned or partially partitioned hurts query performance and manageability. Fixing the statement prevents downtime, restores symmetry, and avoids unpredictable optimizer plans.
The existing definition uses a fixed number of subpartitions per partition. A new ADD PARTITION statement supplies a higher or lower count.
The table is composite-partitioned, but the ADD PARTITION statement forgets to include any SUBPARTITION clause, implicitly creating one subpartition and causing mismatch.
Automation scripts that generate DDL may accidentally reuse a template created for a different partitioning scheme.
Dump files generated on one MySQL version may not align with the target version’s partition syntax, resulting in incorrect subpartition counts.
Raised when both PARTITION and SUBPARTITION options are supplied improperly in CREATE TABLE.
Occurs when a CREATE TABLE statement specifies an invalid number of partitions.
General partitioning error covering multiple syntax and metadata mismatches.
No. MySQL requires every partition in a composite-partitioned table to contain the same number of subpartitions.
Yes. Only InnoDB and NDB support partitioning fully. Other engines may not allow composite partitioning at all.
SHOW CREATE TABLE displays each partition line. Count the SUBPARTITION entries or query information_schema.partitions.
Galaxy’s AI copilot reads your existing partition DDL and suggests ADD PARTITION statements with the correct subpartition count, preventing mismatch errors before execution.
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