16.10 - Fault Isolation Diagnostics - Teradata Database

Teradata Database Administration

Product
Teradata Database
Release Number
16.10
Release Date
April 2018
Content Type
Administration
Publication ID
B035-1093-161K
Language
English (United States)

Fault isolation features capture information specific to the fault without requiring a reset. These failure diagnostics facilitate early analysis of problems before the associated dump is available for examination.

Content and abort handling depends on whether the fault being isolated occurred in the parser, an AMP, or Dispatcher, as described in the following table.

Type of Fault Isolation Description
Dispatcher The Dispatcher prequalifies a fault for fault isolation.

If the fault qualifies for fault isolation, the Dispatcher captures diagnostic data and then aborts the transaction. If the transaction abort completes successfully, then the system avoids a DBS reset.

The diagnostic data consists of a snapshot dump, user session related data, stack backtrace, and the SQL request if it is available. (The last three items listed are captured in the system error log.)

Note, however, that a DBS reset occurs if the fault fails to qualify for fault isolation, or if the system cannot complete the abort of the transaction successfully.

Parser The parser issues a transaction abort and the Snapshot Dump facility captures the cause of the problem.

The data capture includes the dispatcher worker task containing the query text.

AMP (Spool Table) Teradata attempts to recover from the spool error without a reset.

Typically, such an abort is accompanied by an optional Snapshot Dump to help Teradata Customer Support analyze the reason for the AMP failure.

Aborts generated by the AMP Fault Isolation feature:

  • Return a detailed text description of the AMP failure to the associated client session.
  • Log diagnostic details of the failure to the system error log. AMP Fault Isolation also performs this error-logging when the system reset cannot be avoided.
If you need to tune AMP Fault Isolation, contact Teradata Customer Support. They can help modify the settings to:
  • Reduce the cases for which the aborts are enabled.
  • Disable the feature entirely to force a Teradata reset and a dump on the next occurrence of the failure.