How to fix ERROR 1412: Table definition changed, retry transaction in MySQL

import mysql.connector
from mysql.connector import Error

def execute_with_retry(connection, query, max_retries=3):
    for attempt in range(max_retries):
        try:
            cursor = connection.cursor()
            cursor.execute(query)
            connection.commit()
            return cursor.fetchall()
        except Error as e:
            if e.errno == 1412 and attempt < max_retries - 1:
                # Table definition changed, retry
                connection.rollback()
                continue
            else:
                raise
    raise Exception(f"Failed after {max_retries} attempts")

# Usage
try:
    result = execute_with_retry(connection, "SELECT * FROM my_table")
except Error as e:
    print(f"Transaction failed: {e}")

async function executeWithRetry(pool, query, maxRetries = 3) {
  for (let attempt = 0; attempt < maxRetries; attempt++) {
    const connection = await pool.getConnection();
    try {
      await connection.beginTransaction();
      const result = await connection.query(query);
      await connection.commit();
      return result;
    } catch (error) {
      await connection.rollback();
      if (error.code === 'ER_TABLE_DEF_CHANGED' && attempt < maxRetries - 1) {
        // Table definition changed, retry
        await new Promise(resolve => setTimeout(resolve, 100 * Math.pow(2, attempt)));
        continue;
      }
      throw error;
    } finally {
      await connection.release();
    }
  }
}

# Schedule maintenance for off-peak hours
# In your cron configuration:
0 2 * * * /usr/local/bin/run-database-migrations.sh

# Before running migrations, wait for active transactions to complete
# Check current connections:
SELECT COUNT(*) FROM INFORMATION_SCHEMA.PROCESSLIST
WHERE COMMAND != 'Sleep' AND ID != CONNECTION_ID();

# Run migration only when count is low or zero
mysql -u root -p < migrations.sql

# In mysqldump:
mysqldump --single-transaction --all-databases > backup.sql

# Or with mydumper (which handles 1412 better):
mydumper -u root -p password -o /backup/

-- For current session only
SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;

-- Verify the change
SELECT @@session.transaction_isolation;

-- For a single transaction
START TRANSACTION;
SET TRANSACTION ISOLATION LEVEL READ COMMITTED;
SELECT * FROM my_table;
COMMIT;

-- To set globally (requires SUPER privilege)
SET GLOBAL TRANSACTION ISOLATION LEVEL READ COMMITTED;

# Django
DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.mysql',
        'OPTIONS': {
            'isolation_level': 'read committed',
        }
    }
}

# SQLAlchemy
from sqlalchemy import create_engine
engine = create_engine('mysql+pymysql://user:pass@localhost/db',
                      connect_args={'isolation_level': 'read committed'})

-- Acquire metadata locks on tables before backup
FLUSH TABLES table_name FOR EXPORT;

-- Now run your backup safely
-- mysqldump or file copy operations

-- Release locks
UNLOCK TABLES;

-- See all active transactions and their isolation levels
SELECT
  p.ID,
  p.USER,
  p.HOST,
  p.DB,
  p.COMMAND,
  p.TIME,
  p.STATE,
  p.INFO,
  t.TRX_STATE,
  t.TRX_ISOLATION_LEVEL,
  t.TRX_STARTED
FROM INFORMATION_SCHEMA.PROCESSLIST p
LEFT JOIN INFORMATION_SCHEMA.INNODB_TRX t ON p.ID = t.TRX_MYSQL_THREAD_ID
WHERE p.COMMAND != 'Sleep'
ORDER BY t.TRX_STARTED;

-- Kill long-running transactions that block DDL (if safe)
KILL 12345; -- Replace with actual process ID

-- MySQL 8.0+: See blocked operations
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCKS;
SELECT * FROM INFORMATION_SCHEMA.INNODB_LOCK_WAITS;