Determines the interval (in seconds) between deadlock timeout detection cycles. The value in DeadLockTimeout specifies the time-out value for requests that are locking each other out on different AMPs. When the system detects a deadlock, it aborts one of the jobs.
Proxy locks reduce deadlock situations for all-AMP requests that require write or exclusive locks. However, deadlocks still may be an issue on large systems with heavy concurrent usage. In batch operations, concurrent requests may contend for locks on Data Dictionary tables.
Field Group
General
Valid Range
10 though 3600 seconds
Default
240 seconds
Changes Take Effect
After the next database restart.
Recommendation
Reduce the value in this field to cause more frequent retries with less time in a deadlock state. Faster CPUs reduce the system overhead for performing deadlock checks, so you can set the value much lower than the current default of 240 seconds.
| IF your applications… | THEN you should… |
|---|---|
| incur some dictionary deadlocks | set the value to between 30 and 45 seconds. |
| incur few dictionary deadlocks | retain the default value of 240 seconds. |
| incur many true deadlocks | set the value as low as 10 seconds. |
| are mostly online transaction processing (tactical) applications | set the value as low as 10 seconds. |
Related Information
For more information on locks and deadlocks, see SQL Request and Transaction Processing, B035-1142 and Teradata Vantage™ - Database Administration, B035-1093.