# MV\_BLOCKED\_QUERIES

This view shows which queries are waiting, and what they are waiting for. It can be used to help debug unexpected waiting issues.

| Column name           | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| --------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `node_id`             | ID of the node running the blocked query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| `id`                  | ID of the blocked query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| `query_text`          | The text of the blocked query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
| `blocking_node_id`    | ID of the node that is running the blocking query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
| `blocking_id`         | ID of the blocking query.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| `blocking_type`       | Information on the type of block. It can have one of the following values:<ul> <li><code>internal transaction</code>: The query is waiting on an internal background operation that is holding a lock. The background thread may not have a process ID and <code>BLOCKING_ID</code> may be <code>NULL</code> in this case.</li> <li><code>user transaction row lock</code>: The query is waiting on a row-level lock held by another user transaction, for example, when one transaction updates rows that another query needs to read or write.</li> <li><code>user transaction table lock</code>: The query is waiting on a table-level lock held by another user transaction.</li> <li><code>ddl lock</code>: The query is waiting on a DDL operation that holds a lock on a specific table, pipeline object, or at the database level.</li> <li><code>plan compilation lock</code>: The query is waiting for a query plan compilation to complete because the plan (or associated metadata) is currently locked by another compilation or garbage collection.</li> <li><code>database cluster operation lock</code>: The query is waiting on a cluster‑level operation, for example, <code>REBALANCE PARTITIONS</code>.</li> </ul> |
| `blocking_query_text` | The text of the blocking query, or a description of the connection. For example:“open idle transaction”.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |

## Example mv\_blocked\_queries Results

| NODE\_ID | ID | QUERY\_TEXT              | BLOCKING\_NODE\_ID | BLOCKING\_ID | BLOCKING\_TYPE   | BLOCKING\_QUERY\_TEXT |
| -------- | -- | ------------------------ | ------------------ | ------------ | ---------------- | --------------------- |
| 1        | 42 | insert into t values (1) | 1                  | 17           | user transaction | open idle transaction |

Both `id` and `blocking_id` refer to the “id” from `information_schema.processlist`. This means you can join `information_schema.mv_blocked_queries` with `information_schema.processlist` to get more detail about the blocked or blocking process.

Once you know the query or connection responsible for blocking, you can use [KILLALL QUERIES](https://docs.singlestore.com/db/v9.1/reference/sql-reference/operational-commands/killall-queries.md) or [KILL CONNECTION and KILL QUERY](https://docs.singlestore.com/db/v9.1/reference/sql-reference/operational-commands/kill-connection-and-kill-query.md) to unblock your process.

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Modified at: December 4, 2025

Source: [/db/v9.1/reference/information-schema-reference/management/mv-blocked-queries/](https://docs.singlestore.com/db/v9.1/reference/information-schema-reference/management/mv-blocked-queries/)

(An index of the documentation is available at /llms.txt)