E.8 MON$STATEMENTS

MON$STATEMENTS displays statements prepared for execution.

Column Name Data Type Description
MON$STATEMENT_ID BIGINT Statement identifier
MON$ATTACHMENT_ID BIGINT Connection identifier
MON$TRANSACTION_ID BIGINT Transaction identifier
MON$STATE SMALLINT Statement state: 0 - idle 1 - active 2 - stalled
MON$TIMESTAMP TIMESTAMP The date and time when the statement was prepared
MON$SQL_TEXT BLOB TEXT Statement text in SQL
MON$STAT_ID INTEGER Statistics identifier
MON$EXPLAINED_PLAN BLOB TEXT Explained execution plan
MON$STATEMENT_TIMEOUT INTEGER Connection-level statement timeout in milliseconds. When 0 is reported the timeout of MON$ATTACHMENT.MON$STATEMENT_TIMEOUT for this connection applies.
MON$IDLE_TIMER TIMESTAMP WITH TIME ZONE Statement timer expiration time

The STALLED state indicates that, at the time of the snapshot, the statement had an open cursor and was waiting for the client to resume fetching rows.

Display active queries, excluding those running in your connection

1. SELECT
2. ATT.MON$USER,
3. ATT.MON$REMOTE_ADDRESS,
4. STMT.MON$SQL_TEXT,
5. STMT.MON$TIMESTAMP
6. FROM MON$ATTACHMENTS ATT
7. JOIN MON$STATEMENTS STMT ON ATT.MON$ATTACHMENT_ID = STMT.MON$ATTACHMENT_ID
8. WHERE ATT.MON$ATTACHMENT_ID <> CURRENT_CONNECTION
9. AND STMT.MON$STATE = 1

E.8.1 Using MON$STATEMENTS to Cancel a Query

Monitoring tables are read-only. However, the server has a built-in mechanism for deleting (and only deleting) records in the MON$STATEMENTS table, which makes it possible to cancel a running query.

Notes

  • If no statements are currently being executed in the connection, any attempt to cancel queries will not proceed
  • After a query is cancelled, calling execute/fetch API functions will return an error with the isc_cancelled code
  • Subsequent queries from this connection will proceed as normal
  • Cancellation of the statement does not occur synchronously, it only marks the request for cancellation, and the cancellation itself is done asynchronously by the server

ExampleCancelling all active queries for the specified connection:

1. DELETE FROM MON$STATEMENTS
2. WHERE MON$ATTACHMENT_ID = 32