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Performance Tuning

A collection of 267 issues

Maximizing Performance and Space Savings: Teradata Compression Techniques

Introduction to Teradata Compression Note: Teradata Block Level Compression is now permanently enabled and cannot be turned off. Nonetheless, this article remains useful for current Teradata systems utilizing block-level compression. It demonstrates the continued advantages of multi-value compression (Teradata MVC). With Teradata's introduction of block-level compression, the utilization

Teradata strtok_split_to_table, CSVLD, Unpack: Column Splitting in Teradata

Splitting column content can be a challenging task. Teradata provides multiple methods to achieve this, each with unique pros and cons. In this article, we will examine these techniques in detail. To begin, we will generate a table containing sufficient random data to assess every option's efficiency and

Comparing Index Types of SQL Server and Teradata: Clustered vs Row Partitioning, Non-clustered vs NUSI, USI, Join Index, and More

This article compares the index types in SQL Server and Teradata. It can benefit those transitioning between the two platforms to understand their distinctions and overlaps, despite their different architectures. Clustered Index vs Teradata Row Partitioning The SQL Server's clustered index arranges table rows in a specific physical

How the Number of Rows per Data Block Affects Teradata NUSI Selectivity: A Case Study

Teradata NUSI Selectivity and Data-Block Density The goal of this article is to show how the number of rows per base-table data block impacts the selectivity threshold for Non-Unique Secondary Indexes (NUSI) in Teradata. Understanding this correlation is critical when analyzing query plans and tuning indexing strategies. The number of

Understanding Teradata Statistics Histograms: How the Optimizer Estimates Cardinality for WHERE Conditions

Teradata Statistics Histograms - A Short Introduction Many are familiar with the Optimizer's statistical confidence levels. I was recently surprised to discover that a "high confidence" rating does not guarantee a fully accurate estimation (provided the statistics collected are not stale). While I remain hopeful that

Hadoop and Teradata Data Warehousing: A Comparison and Integration Perspective

Hadoop is a buzzword in the world of big data, but its actual value can be concealed by the hype. This article compares Teradata and Hadoop Data Warehousing, highlighting the advantages of leveraging Hadoop's scalability and preprocessing capabilities to improve Teradata's performance. However, the

A Teradata HASHROW Table Difference Screening Test

Have you ever experienced extended waiting times for a table comparison to yield results? Have you ever been compelled to halt and defer quality checks on sizable tables owing to excessive resource utilization during a previous attempt? What if you possessed a straightforward screening test indicating which tables require further

Layer and Preparatory Table Strategies

Teradata Data Type Considerations

Teradata - Merging two change history tables