MySQL 1234: Cannot unlock partition.

When encountering the error "1234: Cannot unlock partition" in a MySQL database and there's no database administrator available, follow these steps immediately:

  1. Check for Active Locks



Run the following SQL query to check if there are any active locks that might be causing the issue:
SHOW OPEN TABLES WHERE In_use > 0;
This will list tables that are currently locked. Identify if the partition in question is part of these tables.

  1. Identify Locking Transactions



To identify which transactions are holding locks, execute:
SHOW ENGINE INNODB STATUS;
Look under the `TRANSACTIONS` section for transactions that are in a `LOCK WAIT` state, or have active locks on the partition or table in question.

  1. Check Process List



Examine the current running processes for any that might be related to the locked partition:
SHOW FULL PROCESSLIST;
This can help identify any long-running queries or transactions that might have acquired a lock on the partition.

  1. Release Locks



If a specific process is identified as holding a lock unnecessarily, it might be safe to terminate it to release the lock, especially if it's stuck or not critical. Do this with caution:
KILL [process ID];
Replace `[process ID]` with the ID of the process you intend to stop.

  1. Check Disk Space



Ensure there's enough disk space on the server as a full disk can sometimes cause issues with unlocking partitions. Use the command line to check disk space:
df -h

  1. Check File System Permissions



Ensure the MySQL process has the necessary permissions to access and modify the partition files. This step requires accessing the server's command line and checking the permissions of the MySQL data directory and its contents.

  1. Restart MySQL Service



If all else fails and you've identified that there's no risk of data corruption or loss, you may try restarting the MySQL service. This can sometimes clear locks that have become stuck due to unforeseen issues. Use the command:
sudo systemctl restart mysql
Or, if not using systemd:
sudo service mysql restart

Please note, steps like killing processes or restarting the MySQL service can lead to data loss or corruption if not done with care. These actions should be taken only when you're confident they won't cause further issues.

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MySQL 1252: Partition does not exist.
MySQL 1251: Key not allowed in partition.
MySQL 1250: Partition key not allowed.
MySQL 1247: Cannot split partition.
MySQL 1249: Cannot update partition index.
MySQL 1248: Cannot update partition schema.
MySQL 1246: Cannot merge partition.
MySQL 1244: Cannot create partition.
MySQL 1245: Cannot drop partition.
MySQL 1243: Statement failed due to partition.
MySQL 1242: Cannot expand partition.
MySQL 1240: Partition is corrupted.
MySQL 1241: Cannot shrink partition.
MySQL 1239: Partition needs repair.
MySQL 1236: Cannot access partition.
MySQL 1238: Cannot repair partition.
MySQL 1237: Partition is full.
MySQL 1234: Cannot unlock partition.
MySQL 1235: Statement not allowed in partition.
MySQL 1232: Cannot delete partition.
MySQL 1231: Cannot update partition.
MySQL 1233: Cannot lock partition.
MySQL 1230: Duplicate partition key.
MySQL 1229: Cannot drop partition.
MySQL 1228: Cannot add partition.
MySQL 1226: Failed to drop partition.
MySQL 1227: Failed to create partition.
MySQL 1222: Too many partitions.
MySQL 1212: Permission denied for key.
MySQL 1225: Duplicate partition name.
MySQL 1224: Partition not empty.
MySQL 1223: Partition key was not found.
MySQL 1221: Cannot delete parent row.
MySQL 1220: Cannot update parent row.
MySQL 1219: Cannot update child row.
MySQL 1216: Cannot delete or update a parent row.
MySQL 1218: Cannot delete child row.
MySQL 1215: Cannot add foreign key constraint.
MySQL 1217: Cannot add child row.
MySQL 1214: Row was updated.
MySQL 1213: Deadlock found when trying to get lock.
MySQL 1208: Failed to drop key.
MySQL 1211: Too many open files.
MySQL 1210: Key already exists.
MySQL 1209: Key not found.
MySQL 1204: Cannot update entry.
MySQL 1206: Error in unique key constraint.
MySQL 1207: Duplicate key found.
MySQL 1205: Error in foreign key constraint.
MySQL 1203: Cannot insert entry.
MySQL 1202: Cannot delete entry.
MySQL 1199: Statement failed due to index.
MySQL 1200: Index is corrupted.
MySQL 1201: Duplicate key value.
MySQL 1198: Error closing file.
MySQL 1193: Statement failed due to table.
MySQL 1197: Failed to open file.
MySQL 1175: Statement not allowed in schema.
MySQL 1196: Too many connections.
MySQL 1194: Table needs repair.
MySQL 1195: Table is corrupted.
MySQL 1192: Statement failed due to view.
MySQL 1191: Statement failed due to procedure.
MySQL 1189: Statement failed due to event.
MySQL 1190: Statement failed due to function.
MySQL 1186: SAVEPOINT cannot be rolled back.
MySQL 1188: Statement failed due to trigger.
MySQL 1187: Statement failed due to SAVEPOINT.
MySQL 1185: SAVEPOINT does not exist.
MySQL 1184: Cannot use SAVEPOINT in transaction.
MySQL 1183: Command not allowed in transaction.
MySQL 1182: Connection was closed.
MySQL 1181: Duplicate transaction.
MySQL 1180: Read-only transaction violation.
MySQL 1179: Transaction is read-only.
MySQL 1176: Statement not allowed in session.
MySQL 1178: Transaction not active.
MySQL 1177: Session not open.
MySQL 1174: Statement not allowed in row.
MySQL 1173: Statement not allowed in table.
MySQL 1172: Statement not allowed in transaction.
MySQL 1170: Cannot open database.
MySQL 1171: Null column in table.
MySQL 1169: Duplicate key.
MySQL 1168: Failed to create file.
MySQL 1167: Out of disk space.
MySQL 1165: Error reading from file.
MySQL 1166: Error writing to file.

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