The information provided in this discussion is designed to help you to interpret EXPLAIN reports more accurately and to explain and emphasize the importance of maintaining accurate statistical and demographic profiles of your data. This discussion does not describe query optimization in detail.
Join processing is described in Join Planning and Optimization.
- Query Rewrite
- Examples: Query Rewrites
- Query Optimizers
- Teradata Optimizer Processes
- Incremental Planning and Execution
- Translation to Internal Representation
- Optimizer Statistics and Demographics
- How the AMP Software Collects Statistics
- Interval Histograms
- Sampled Statistics
- Dynamic AMP Sampling
- Comparing Accuracies of Methods of Collecting Statistics
- Optimal Times to Collect or Recollect Statistics
- Optimizer Use of Statistical Profiles
- Using Interval Histograms to Make Initial Cardinality Estimates
- Determining the Reliability of Statistics from History Intervals
- Derived Statistics
- Statistical Inheritance by Join Indexes
- Deriving Column Demographics
- Using Join Index Statistics to Estimate Single-Table Expression Cardinalities
- Using Unique Join Index in Access Path for Query
- Estimating Join Cardinality with Single-Row Unique Index Access to One of the Tables
- Stale Statistics