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Indexing

A collection of 141 issues

Optimizing Teradata Joins with Skewed Data: Strategies and Solutions

Skewed Teradata Joins - The Initial Situation Consider the scenario where one table includes various currencies while the other comprises customers' accounts with their corresponding currency. Essentially, the ISO code of the currency serves as a foreign key in the account table. CREATE TABLE Currency ( CURRENCY_CD VARCHAR(20)

Using Sparse Maps in Teradata 16.10 for Efficient Distribution of Small Tables Across AMPs

Teradata 16.10 introduces Sparse Maps, a feature to place small table rows on one AMP. Learn more about how it can optimize your system here.

Teradata Data Access: Single-AMP vs. All-AMP Binary Search and Sequential Search

Teradata Heuristics for Nonindexed Columns

Learn about heuristics in Teradata optimizer and how they estimate the number of selected data rows for nonindexed columns in WHERE condition predicates. This post analyzes several queries and their estimates based on heuristics and provides insights on how to replace heuristic estimations with more

How to Optimize Joins in Teradata: A Case Study

Learn how to optimize joins in Teradata with this case study. Discover how simple changes in query text can improve query performance.

How to Use Biased Value Histograms for Accurate Statistics Estimation on Teradata SQL

Learn how biased value histograms store exact cardinalities and provide up-to-date statistics for queries, and witness how the Optimizer estimates the number of rows for a given query.

Teradata Tuning Ideas: Best Practices and Strategies

Learn how to optimize Teradata performance with these general tuning ideas. From changing one parameter at a time to testing on the target system.

The Teradata NUSI (Nonunique Secondary Index)

The Teradata NUSI is an alternative access path to table rows, similar to other relational database indexes. Indexes are used to minimize resource consumption, especially IOs. Unlike Oracle, Teradata employs a hashing method for indexing, which is a common method for shared-nothing database systems. Amazon Redshift and Postgres-based database systems

Teradata PPI: Understanding Partitioned Primary Index for Improved Performance

Learn about the benefits of partitioned primary index (PPI) in Teradata, a method for reducing I/Os and improving performance in database systems.

What is Block Level Compression (BLC) and How Does it Work for Teradata?

Block Level Compression (BLC) is a feature that allows compression of entire data blocks, leading to disk space reduction. Read on to know more.