An ALTER TABLE (add column, change data type, rename column) executes while ADF Copy activities or dbt models hold open transactions reading or writing to the same table.. Online DDL operations like CREATE INDEX or OPTIMIZE TABLE invalidate InnoDB's internal table cache (the data dictionary version), forcing all open transactions on that table to abort.. Automated migration scripts (Flyway, Liquibase, Alembic) run on a cron schedule that overlaps with pipeline execution windows — neither system is aware of the other's schedule.. A DBA runs an ad-hoc ALTER TABLE in a production MySQL instance during business hours while scheduled pipelines are actively extracting data from the same source tables.. MySQL replica promotion or failover triggers implicit DDL (e.g., re-creating temporary tables or adjusting auto_increment counters) that conflicts with long-running read transactions from reporting queries or BI tools.

Step 1: Confirm the error is transient by retrying the failed transaction. In a MySQL client: re-execute the same query. If it succeeds, the issue is purely a DDL timing collision — no schema or data fix is needed.. Step 2: Identify which DDL caused the collision. Run: `SELECT event_time, argument FROM mysql.general_log WHERE command_type = 'Query' AND argument LIKE 'ALTER%' ORDER BY event_time DESC LIMIT 10;` — if general_log is off, check your migration tool's logs (Flyway: `flyway_schema_history`, Liquibase: `DATABASECHANGELOG`).. Step 3: Configure retry on ADF activities. Open the pipeline in ADF Studio → select the failed activity → Settings tab → set Retry to 3 and Retry interval (seconds) to 30. This handles transient 1412 errors without manual intervention.. Step 4: Schedule DDL migrations outside pipeline windows. If pipelines run every hour at :00, schedule migrations at :30. In cron: `30 * * * * /usr/local/bin/flyway migrate`. This eliminates the overlap window entirely.. Step 5: For large tables where ALTER TABLE takes minutes, use pt-online-schema-change: `pt-online-schema-change --alter 'ADD COLUMN new_col INT' D=mydb,t=my_table --execute`. This creates a shadow table and swaps atomically — open transactions on the original table are not interrupted.. Step 6: As an alternative, use gh-ost: `gh-ost --database=mydb --table=my_table --alter='ADD COLUMN new_col INT' --execute`. gh-ost uses binlog streaming instead of triggers, which puts less load on the source server during the migration.. Step 7: Monitor for recurrence. Run: `SHOW GLOBAL STATUS LIKE 'Com_alter%';` periodically to track DDL frequency. Cross-reference DDL timestamps with pipeline failure timestamps to confirm the conflict window is resolved.

High severityresource

MySQL Error:
1412, Please Retry Transaction

What does this error mean?

MySQL returns error 1412 (ER_TABLE_DEF_CHANGED) when a transaction tries to access a table whose definition was modified by a concurrent DDL statement (ALTER TABLE, CREATE INDEX, DROP COLUMN, etc.) after the transaction opened its snapshot. InnoDB detects that the table's internal version number no longer matches the version the transaction started with, and forces a rollback. In data pipelines this typically surfaces as a failed ADF Copy activity, a dbt model error, or a Linked Service query timeout. The error message reads 'Table definition has changed, please retry transaction' — the key word is 'retry': MySQL has already rolled back cleanly, and re-executing the same transaction against the updated schema will succeed. The root cause is almost always a timing collision between schema migrations and scheduled pipeline runs.

Common causes

1An ALTER TABLE (add column, change data type, rename column) executes while ADF Copy activities or dbt models hold open transactions reading or writing to the same table.
2Online DDL operations like CREATE INDEX or OPTIMIZE TABLE invalidate InnoDB's internal table cache (the data dictionary version), forcing all open transactions on that table to abort.
3Automated migration scripts (Flyway, Liquibase, Alembic) run on a cron schedule that overlaps with pipeline execution windows — neither system is aware of the other's schedule.
4A DBA runs an ad-hoc ALTER TABLE in a production MySQL instance during business hours while scheduled pipelines are actively extracting data from the same source tables.
5MySQL replica promotion or failover triggers implicit DDL (e.g., re-creating temporary tables or adjusting auto_increment counters) that conflicts with long-running read transactions from reporting queries or BI tools.

How to fix it

1Step 1: Confirm the error is transient by retrying the failed transaction. In a MySQL client: re-execute the same query. If it succeeds, the issue is purely a DDL timing collision — no schema or data fix is needed.
2Step 2: Identify which DDL caused the collision. Run: `SELECT event_time, argument FROM mysql.general_log WHERE command_type = 'Query' AND argument LIKE 'ALTER%' ORDER BY event_time DESC LIMIT 10;` — if general_log is off, check your migration tool's logs (Flyway: `flyway_schema_history`, Liquibase: `DATABASECHANGELOG`).
3Step 3: Configure retry on ADF activities. Open the pipeline in ADF Studio → select the failed activity → Settings tab → set Retry to 3 and Retry interval (seconds) to 30. This handles transient 1412 errors without manual intervention.
4Step 4: Schedule DDL migrations outside pipeline windows. If pipelines run every hour at :00, schedule migrations at :30. In cron: `30 * * * * /usr/local/bin/flyway migrate`. This eliminates the overlap window entirely.
5Step 5: For large tables where ALTER TABLE takes minutes, use pt-online-schema-change: `pt-online-schema-change --alter 'ADD COLUMN new_col INT' D=mydb,t=my_table --execute`. This creates a shadow table and swaps atomically — open transactions on the original table are not interrupted.
6Step 6: As an alternative, use gh-ost: `gh-ost --database=mydb --table=my_table --alter='ADD COLUMN new_col INT' --execute`. gh-ost uses binlog streaming instead of triggers, which puts less load on the source server during the migration.
7Step 7: Monitor for recurrence. Run: `SHOW GLOBAL STATUS LIKE 'Com_alter%';` periodically to track DDL frequency. Cross-reference DDL timestamps with pipeline failure timestamps to confirm the conflict window is resolved.

Example log output

ErrorCode=UserErrorFailedToConnectMySqlServer,'Type=Microsoft.DataTransfer.Common.Shared.HybridDeliveryException,Message=Error occurred when trying to execute query. Error message from MySQL database: Table definition has changed, please retry transaction,Source=Microsoft.DataTransfer.ClientLibrary'
[2026-05-11 02:14:37] [error] dbt.adapters.mysql: Database Error in model stg_orders (models/staging/stg_orders.sql)
  1412 (HY000): Table definition has changed, please retry transaction
  compiled Code at target/compiled/my_project/models/staging/stg_orders.sql

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.

Source · dev.mysql.com/doc/mysql-errors/8.0/en/server-error-reference.html