The Pitfalls of Teradata SELECT * Queries

sql2

Introduction In a row-oriented database engine like Teradata, data is organized and stored in units called data blocks. Each data block features a fixed header and accommodates multiple rows. Every row consists of a record header followed by its corresponding columns. When a database retrieves and stores a data block in the cache, it accesses …

Read more

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

arch2

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 order, making it ideal for range-based queries. …

Read more

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

tune4

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 qualifying rows that make a NUSI …

Read more

Optimizing Teradata Performance through Statistics and Primary Index Selection

sql2

1. Statistics In Teradata, understanding and managing statistics is essential for optimizing database performance. Statistics provide the optimizer with precise data about stored information, allowing for well-informed decisions when handling queries. This article will explore the significance of statistics in Teradata, their effect on query performance, and recommended methods for upkeep. The Role of Statistics …

Read more

Teradata MERGE INTO vs. UPDATE: Performance Comparison and Limitations

sql1

Teradata MERGE INTO vs. UPDATE This article compares the UPDATE statement to the MERGE INTO statement, analyzing their respective performance differences and limitations. The Teradata MERGE INTO statement positively impacts performance by reducing I/O operations through the following properties. MERGE INTO offers an advantage in lower IOs as Teradata processes each data block only once …

Read more

Designing Teradata Row Partitioning for Optimal Performance in Tactical Workloads

tune3

Teradata is commonly used for tactical workloads and OLTP applications in my projects. However, it is crucial to avoid designing databases carelessly. Teradata excels as a database for strategic data warehousing. High-performance queries can often be achieved without special design techniques. Keeping statistics current and correctly designing row partitioning is typically sufficient, while other indexes …

Read more

DWHPro

Expert network for enterprise data platforms. Senior consultants, project teams built for your challenge — across Teradata, Snowflake, Databricks, and more.

📍Vienna, Austria & Jacksonville, Florida

Quick Links
Services Team Teradata Book Blog Contact Us
Connect
LinkedIn → [email protected]
Newsletter

Join 4,000+ data professionals.
Weekly insights on Teradata, Snowflake & data architecture.