EC
1719
MySQLERRORCommonInnoDBHIGH confidence

InnoDB undo log is full; cannot rollback the transaction

Production Risk

High — transaction fails and must be rolled back; undo log needs manual management.

What this means

The InnoDB undo log tablespace has been exhausted. Long-running transactions that generate large undo entries eventually fill the undo log.

Why it happens
  1. 1Very large or long-running transaction.
  2. 2Undo tablespace is too small relative to transaction volume.
  3. 3innodb_undo_log_truncate is disabled.
How to reproduce
trigger — this will error
trigger — this will error
-- Long transaction updating millions of rows without committing.

expected output

ERROR 1719 (HY000): Undo log is full; cannot execute DML.

Fix 1

Break large transactions into smaller batches

Break large transactions into smaller batches
-- Instead of one large UPDATE:
UPDATE large_table SET col = val WHERE id BETWEEN 1 AND 10000;
COMMIT;
UPDATE large_table SET col = val WHERE id BETWEEN 10001 AND 20000;
COMMIT;

Why this works

Committing frequently reduces the undo log footprint per transaction.

Fix 2

Enable undo log truncation

Enable undo log truncation
SET GLOBAL innodb_undo_log_truncate = ON;
SET GLOBAL innodb_purge_rseg_truncate_frequency = 128;

Why this works

Truncation allows InnoDB to reclaim undo tablespace after purge.

What not to do

✕

Sources
Official documentation ↗

MySQL 8.0 — 1719 ER_INNODB_UNDO_LOG_FULL

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