An ALTER TABLE runs while ADF copy activities or dbt models have open transactions on the table. Online DDL operations (adding indexes, changing columns) invalidate the table cache used by existing transactions. Migration scripts run during active pipeline windows without proper coordination

Step 1: Retry the transaction — MySQL rolls back the affected transaction and the client should retry.. Step 2: Schedule DDL operations during pipeline maintenance windows when no transactions are active on the table.. Step 3: For ADF, configure retry on the activity: MySQL will release the DDL lock once all open transactions close.. Step 4: Use pt-online-schema-change or gh-ost for large table DDL changes to minimize the impact window.

High severityresource

Power BI Refresh Error:
1412

What does this error mean?

A DDL change (ALTER TABLE, CREATE INDEX, etc.) was executed while an open transaction was using the table.

Common causes

1An ALTER TABLE runs while ADF copy activities or dbt models have open transactions on the table
2Online DDL operations (adding indexes, changing columns) invalidate the table cache used by existing transactions
3Migration scripts run during active pipeline windows without proper coordination

How to fix it

1Step 1: Retry the transaction — MySQL rolls back the affected transaction and the client should retry.
2Step 2: Schedule DDL operations during pipeline maintenance windows when no transactions are active on the table.
3Step 3: For ADF, configure retry on the activity: MySQL will release the DDL lock once all open transactions close.
4Step 4: Use pt-online-schema-change or gh-ost for large table DDL changes to minimize the impact window.

Frequently asked questions

Is MySQL error 1412 always safe to retry?

Yes — MySQL rolls back the transaction cleanly before returning this error. The retry starts a fresh transaction on the updated table definition.

How do I run MySQL schema migrations without interrupting running pipelines?

Use pt-online-schema-change (Percona Toolkit) or gh-ost (GitHub) for online schema changes on large tables — these tools copy data to a shadow table without blocking reads or writes.

Can MetricSign detect when schema migration and pipeline conflicts cause failures?

Yes — MetricSign captures ADF pipeline failures and surfaces the MySQL error code, helping you identify when DDL migrations are clashing with scheduled pipeline runs.

Official documentation: https://dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html