EC
1664
MySQLERRORNotableSchemaHIGH confidence

Unknown ALTER TABLE ALGORITHM value

Production Risk

Low — the ALTER is rejected; no data change.

What this means

The ALGORITHM clause in an ALTER TABLE statement specifies an unrecognised algorithm name.

Why it happens
  1. 1A typo or unsupported value was used in ALGORITHM=.
How to reproduce
trigger — this will error
trigger — this will error
ALTER TABLE t ADD COLUMN x INT, ALGORITHM=FASTCOPY;

expected output

ERROR 1664 (HY000): Unknown ALGORITHM 'FASTCOPY'.

Fix

Use a valid ALGORITHM value

Use a valid ALGORITHM value
ALTER TABLE t ADD COLUMN x INT, ALGORITHM=INPLACE;
-- Valid values: DEFAULT, INPLACE, COPY, INSTANT (MySQL 8.0+)

Why this works

Specifying a supported algorithm name resolves the parse error.

Version notes

Sources
Official documentation ↗

MySQL 8.0 — 1664 ER_UNKNOWN_ALTER_ALGORITHM

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