Investigating Query Blocks and Delays - Teradata Database

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Investigating Query Blocks and Delays

Most blocks are momentary and do not require attention. However, if a block persists, you can investigate it to identify the cause and determine whether further action is required.

1 Use the Teradata Viewpoint Query Monitor portlet to monitor the parameters related to query blocks and delays.





Indicates that a session query is held up by a lock on an object that the query is attempting to access.

Blocked Time

How long the query has been blocked.

Momentary locks are a normal part of database operation. Persistent locks may indicate:

  • A runaway query or hung query that cannot complete and release its locks, and which should be aborted
  • A long-executing query, such as large-scale update or backup operation, which should be rescheduled to avoid resource contention
  • Delayed

    Indicates that the query is in a delay queue caused by a workload rule.

    2 Click the session ID for the query to access the Details View.

  • If a query is blocked, see the Blocked By tab for details
  • If the query is delayed, the Delay tab provides details about the cause of the delay
  • 3 You can also use the Lock Viewer portlet to find out additional details about the block:

  • Block Time
  • Database
  • Table
  • Delay
  • Blocked User
  • Blocking Level
  • Blocking User
  • Additional Tools for Analyzing Lock Problems

    The following table provides suggestions for analyzing and solving lock problems.





    Lock Display

    Transaction locks

    Determine which session is holding the lock that blocks others.

    Query Session

    Blocked session

    Abort the session causing blocked transactions.

    Show Locks

    Host utility (HUT) locks; that is, locks placed by a client-based utility, such as Archive and Recovery

    Submit RELEASE LOCKS as either an Archive and Recovery command or an SQL statement.