16.50 - Blocked by Tab for Teradata Database - Teradata Workload Management

Teradata® Viewpoint User Guide

Teradata Viewpoint
Teradata Workload Management
January 2021
User Guide

When a query is blocked, use the Blocked By tab to identify the other queries blocking the selected query. By reviewing the number and type of queries blocking the selected query, you can identify blocking issues on the system, determine the impact of this blocking on the selected query and, based on this information, decide the best course of action to resolve the issue.

The information in this tab is read-only. The tab is available only when the selected query is blocked. You can drill down into the session information for the blocking session. Use the Session ID link when connected to Teradata Database 14.10 and earlier, and click anywhere in a row in the table when connected to Teradata Database 15.0 and later.

The following information is available in the noted versions of Teradata Database.
Blocked By Information Description 14.10 and earlier 15.00 and later
Session ID Unique session identifier of the query that is blocking Available Available
Username Name of the user that is running the query that holds the lock Available Available
State Icon Icon representing the current state of the query   Available
Blocking Type Indicates the significance of the blocker. Available values are:
  • Root Cause - Sessions that are not blocked, but are causing other sessions to be blocked
  • Granted - Sessions that are blocked and are blocking other sessions because they have been granted a lock
  • Waiting - Sessions that are blocked and are ahead of other blocked sessions in the queue
Blocking Count Total number of sessions that are either directly or indirectly blocked by this session   Available
Blocking Time Amount of elapsed time that this session has been blocking other sessions, displayed as
  • d +hh :mm :ss
Blocking Impact Blocked time summed together of each session that is either directly or indirectly blocked by this session, displayed as
  • d +hh :mm :ss
Blocking Locks A comma-separated list of the locks that are responsible for the blocking, for example:

Granted write lock on table databaseName.tableName, Waiting on write lock on rowhash databaseName.tableName

The information displays in the following order:
  1. Status of the lock causing the block (Waiting or Granted)
  2. Mode (severity) of the lock involved in causing a block (exclusive, write, read, or access)
  3. Type of object whose lock is causing the session described by the associated row to be blocked (database, table, row hash, table partition range, row hash partition range, row hash partition, and row key range)
  4. Name of the database object over which a lock conflict is preventing the session from being granted a lock
  5. Name of the table object over which a lock conflict is preventing the session from being granted a lock
Host Host ID or LAN ID associated with the PE that processed the login request for the session Available  
Lock Type Type of lock. Type can be Exclusive, Read, Write, or Access Available  
Status Lock status. Status can be Waiting or Granted Available  
Locked Name of the locked object Available