> For the complete documentation index, see [llms.txt](https://mariadb.com/docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mariadb.com/docs/analytics/mariadb-columnstore/management/node-maintenance-for-mariadb-enterprise-columnstore/view-clear-table-locks.md).

# View and Clear Table Locks

View and clear lingering table locks in MariaDB ColumnStore using viewtablelock and cleartablelock, useful when a failed DDL or bulk load leaves a table locked.

MariaDB ColumnStore acquires table locks for some operations, and it provides utilities to view and clear those locks.

MariaDB ColumnStore acquires table locks for some operations, such as:

* DDL statements
* DML statements
* Bulk data loads

If an operation fails, the table lock does not always get released. If you try to access the table, you can see errors like the following:

```
ERROR 1815 (HY000): Internal error: CAL0009: Drop table failed due to IDB-2009: Unable to perform the drop table operation because cpimport with PID 16301 is currently holding the table lock for session -1.
```

To solve this problem, MariaDB Enterprise ColumnStore provides two utilities to view and clear the table locks:

* `cleartablelock`
* `viewallxml`
* `viewtablelock`

## Viewing Table Locks

The `viewtablelock` utility shows table locks currently held by MariaDB Enterprise ColumnStore:

To view all table locks:

```bash
viewtablelock
 There is 1 table lock

  Table                     LockID  Process   PID    Session   Txn  CreationTime               State    DBRoots
  hq_sales.invoices         1       cpimport  16301  BulkLoad  n/a  Wed April 7 14:20:42 2021  LOADING  1
```

To view table locks for a specific table, specify the database and table:

```bash
viewtablelock hq_sales invoices
 There is 1 table lock

  Table                     LockID  Process   PID    Session   Txn  CreationTime               State    DBRoots
  hq_sales.invoices         1       cpimport  16301  BulkLoad  n/a  Wed April 7 14:20:42 2021  LOADING  1
```

## Identifying Failed Transactions

Sometimes, a problem with a rollback transaction can result in the DBRM setting the system to read-only and failing to release the table lock. To identify if there is a stuck or failed rollback of a transaction, you can utilize the `viewallxml` command. This utility helps read the active transaction XML files and pinpoints orphaned or hanging transactions that might be preventing standard lock clearance.

## Clearing Table Locks

The `cleartablelock` utility clears table locks currently held by MariaDB Enterprise ColumnStore.

To clear a table lock, specify the lock ID shown by the `viewtablelock` utility:

```
cleartablelock 1
```

### Forced Releases for Lingering Locks

In certain situations, using the standard `cleartablelock <id>` command does not unlock a table lock. You may encounter an error indicating the lock is not found or still in use:

```
Rollback error: Unable to grab lock; Lock not found or still in use.
Table lock 54303 for table edf_colstore.pl_cs_tracking_summary_t is not cleared.
```

If a table lock remains stuck, you can utilize the `-l` flag to forcefully release it.

* Note: This is an undocumented and experimental flag.
* To force clear the lock, execute: `cleartablelock -l <id>`.

```bash
root@vm-uks-edf-maria:/var/log/mariadb/columnstore# cleartablelock -l 54303
Clearing table lock 54303 for table edf_colstore.pl_cs_tracking_summary_t

Table lock 54303 for table edf_colstore.pl_cs_tracking_summary_t is cleared.
```

<sub>*This page is: Copyright © 2026 MariaDB. All rights reserved.*</sub>

{% @marketo/form formId="4316" %}