Recommendations for Common Query Problems - Teradata Database

Teradata Database Administration

Teradata Database
Release Number
English (United States)
Last Update
Product Category

You can monitor queries using the Teradata Viewpoint Query Monitor portlet and other tools and utilities to identify poorly performing queries. Poor query performance is usually due to:


Query Problem


Stale statistics

The optimizer uses statistics to plan query execution. If the statistics are out of date, the optimizer may create a poor plan.

Recommendation: Review tables to see whether statistics are out of date, and recollect statistics if required, as shown in Chapter 14: “Improving Query Performance Using COLLECT STATISTICS: Application DBAs.”

Badly skewed data

Causes table rows to be distributed unevenly among AMPs and queries to execute unevenly, which slows processing time.

Recommendation: Monitor table skew. Redefine the primary index if required. See “Finding and Fixing Skewed Tables” on page 247.

Poor query construction

Poor SQL syntax or missed punctuation can result in bad queries.


  • Identify underperforming queries and the users responsible for them. See “Identifying Poorly Performing Queries” on page 246.
  • Abort underperforming queries when required. See “Controlling Poorly Performing Queries” on page 247.
  • Concurrency issues

    Some queries are delayed or prevented from executing because of lock contentions, or the relative priorities of concurrent queries.


  • Identify the cause of a delayed query. See “Investigating Query Blocks and Delays” on page 499.
  • Release a query from the throttle delay cue. See “Controlling Poorly Performing Queries” on page 247.
  • Order the release of requests from the throttle delay queue based on workload priority, instead of first in, first out. See the General tab in the Teradata Viewpoint Workload Designer portlet.
  • Change the priority for a database operation or user.
  • Establish more detailed concurrency controls using TASM.