SingleStore Managed Service

mv_blocked_queries

The mv_blocked_queries view in the information_schema database provides a summary of activities that are currently unable to complete (blocked queries) because they are blocked by another activity (blocking queries).

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. Could be internal transaction, user transaction, or a DDL lock for a specific type of object (table, database, pipeline, etc.).

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 or KILL CONNECTION to unblock your process.