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 accurate ones.
Learn how to optimize joins in Teradata with this case study. Discover how simple changes in query text can improve query performance.
Natural skew may hinder join performance, but the PDPR capability in Teradata 14 can alleviate this problem. However, PDPR may not detect all potential applications if skewed values are not evident in the statistics. If your Teradata version is below 14, PDPR is unavailable. To address this, you can use a technique based on the …
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 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 also utilize hashing. Teradata has …
Learn about the benefits of partitioned primary index (PPI) in Teradata, a method for reducing I/Os and improving performance in database systems.
Learn about the latest improvements in Teradata 14.00 that allow you to customize the collection of statistics to better suit your needs. These improvements include the option to set different sample sizes, consider more bytes for histogram creation, and choose the number of intervals for building statistics histograms. Read on to discover how these changes can benefit your optimization efforts.
Block Level Compression (BLC) is a feature that allows compression of entire data blocks, leading to disk space reduction. Read on to know more.
Learn about the Teradata Hash Index, designed to minimize disk IOs and improve access to rows. Discover how it differs from Single Table Join Indexes.
Learn how to optimize SQL tuning on Teradata by minimizing I/Os and maximizing parallelism, which can be achieved by evenly distributing rows across all AMPs.
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