EC
3128
MySQLERRORNotableDDLHIGH confidence

ALTER TABLE not supported: AUTO_INCREMENT change requires table copy

Production Risk

Low — AUTO_INCREMENT changes are metadata operations; main risk is table lock during COPY.

What this means

Changing the AUTO_INCREMENT value or adding an AUTO_INCREMENT column cannot be done with ALGORITHM=INPLACE in this context and requires a table copy.

Why it happens
  1. 1AUTO_INCREMENT attribute added or modified while ALGORITHM=INPLACE is forced.
  2. 2Decreasing the AUTO_INCREMENT counter requires a table rebuild.
How to reproduce
trigger — this will error
trigger — this will error
ALTER TABLE t1 AUTO_INCREMENT = 1000, ALGORITHM=INPLACE;

expected output

ERROR 3128 (HY000): ALGORITHM=INPLACE is not supported. Reason: AUTO_INCREMENT change requires table copy.

Fix 1

Use ALGORITHM=COPY

Use ALGORITHM=COPY
ALTER TABLE t1 AUTO_INCREMENT = 1000, ALGORITHM=COPY;

Why this works

Full rebuild allows the AUTO_INCREMENT counter to be reset.

Fix 2

Use default algorithm

Use default algorithm
ALTER TABLE t1 AUTO_INCREMENT = 1000;

Why this works

MySQL selects the appropriate algorithm automatically.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 3128 ER_ALTER_OPERATION_NOT_SUPPORTED_REASON_AUTOINC2

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