16.10 - Global Configuration Parameter - Teradata Unity

Teradata Unity User Guide

Teradata Unity
Release Number
January 2018
English (United States)
Last Update
Parameter Default Valid Values Description
DataFileAsyncNonBlockingWrite True   Data files are distributed across regions asynchronously by default. However, this is limited by network capacity. If the parameter is set to False, data file writes pause if the outstanding data on a network buffer to a remote node exceeds the threshold. Once the outstanding data is consumed and is under the threshold, the data writes continue. The threshold is set with the configuration parameter DfsAsyncWriteMaxOutstandingMegaBytes. If the parameter is set to True, data file writes do not pause when the amount of outstanding data on the network buffer to a remote node exceeds the threshold. Data writes proceed as fast as the local disk can write. Unity DFS reads the unsent data from the local file copies and sends to a remote node once the amount of outstanding data is within the threshold. This parameter should only be configured by GSC.
DfsAsyncWriteMaxOutstandingMegaBytes 50 megabytes 1 to infinity Maximum amount of outstanding DFS file data on a network buffer for asynchronous writes to a remote node. If reached, data files writes either wait (blocking mode) or not wait (non-blocking mode), depending on the DataFileAsyncNonBlockingWrite setting.
GatewayMonitorMinTimeout 2 Process Type or Per Process Minimum period of time (in milliseconds) for the Monitor to start up for each Gateway. If the Gateway does not respond, it is marked as down, and the timeout is adjusted by the value in GatewayMonitorTimeoutAdjust.
GatewayMonitorTimeoutAdjust 2 Process Type or Per Process Number of milliseconds the period of time allowed for the Gateway handshake increases.
GatewayMonitorMaxTimeout 3 Process Type or Per Process Maximum period of time (in milliseconds) allowed when attempting a handshake with the Gateway.
GlobalDeadlockDetectionInterval 0 seconds 0, 10 seconds to infinity This interval in seconds determines how often Unity will detect a global deadlock between Unity and the Teradata database. Unity reads the session-level statistics from the Teradata database. The Teradata database updates its session-level statistics at an interval set by the session rate for the Teradata database. Accounting for both rates, the longest time to detect a deadlock between Unity and the Teradata database is the session rate for the database plus the time set in the GlobalDeadlockDetectionInterval.

The value 0 (zero) disables the setting. This is the default value.

OperationPurgeTime 168 hours   Sets the default expiration period in hours after which a completed operation can be purged from the Unity repository.

To purge operations immediately after they complete, set the expiration time to 0 (zero) hours.

The last operation on a valid object, such as a table, or a system is not purged to ensure the persistence of a history for the object.

PassiveRoutingEnabledEnab Enabled*   Enables the passive routing feature. For installations of Unity15.10 or later, the parameter is enabled. *For installations being upgraded from Unity 14.11, the parameter is set to disabled by default.

To use the passive routing feature, set this parameter to enabled once the entire cluster has been upgraded to 15.10 or later.

SetReadOnlyOnWriteFailure true   With the default value (True), when a recoverable transient error occurs on a request that reads and writes to multiple tables, all the tables being read from are placed in the Read-Only state. All the tables being written to are placed in the Interrupted state. If the feature is turned off (False), all the tables being written are placed in an Interrupted state, while the tables being read remain Active.