Statistics Archives - Page 3 Of 7 -

Optimizing Teradata Performance through Statistics and Primary Index Selection

04/11/202605/03/2023 by Roland Wenzlofsky

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 …

How to Simplify Database-to-Database Table Copying with Teradata Parallel Transporter (TPT) and tdload

04/11/202605/03/2023 by Roland Wenzlofsky

The Teradata Parallel Transporter (TPT) is a Teradata Tools and Utilities (TTU) product. Teradata TPT offers under one roof an SQL-like scripting language that simplifies the syntax of old Teradata Utilities for handling external data (e.g., FastLoad, MultiLoad, TPump, BTEQ, and FastExport). Copying Tables between Teradata Systems A classic approach to perform a database-to-database table …

Streamlining Table Cloning in Teradata and Leveraging Zero-Copy Cloning in Snowflake

04/11/202605/02/2023 by Roland Wenzlofsky

Table cloning is required for purposes such as data backup, testing, and replication. Teradata, a leading data warehousing platform, provides an efficient method for cloning tables. However, Snowflake, a cloud-based data warehousing platform, offers an even more effective approach with its zero-copy cloning feature. This article will compare table cloning in Teradata with Snowflake’s zero-copy …

Teradata Join Strategy: The Benefits and Costs of Merge and Product Join Methods

04/11/202605/02/2023 by Roland Wenzlofsky

Teradata employs various join methods and techniques to merge the rows of two tables onto a single AMP, which is essential for joining. The combination of join technique and data geography is called the join strategy, and its goal is to reduce resource consumption (CPU seconds, I/Os). Some join methods, like the Teradata Merge Join, …

Teradata Tactical Workload

04/11/202605/02/2023 by Roland Wenzlofsky

Introduction This blog post discusses tactical workloads on a Teradata system. Despite Teradata’s implementation of features that support tactical workloads, this workload category remains challenging to manage. Selecting an optimal physical design is essential to meet user expectations for query speed. Designing the Teradata tactical workload on a test environment can be frustrating, especially when …

Tracking Teradata Statistics Usage with StatUseCountV

04/11/202605/02/2023 by Roland Wenzlofsky

How to find out if the Teradata Statistics we created for a specific workload are used? Teradata statistics greatly affect SQL query efficiency. We need a reliable method to get this information. Various objects, such as tables and join indexes, can have statistics collected on them. As performance tuners, it is important to confirm their …

Designing Teradata Row Partitioning for Optimal Performance in Tactical Workloads

04/11/202605/02/2023 by Roland Wenzlofsky

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 …

The Importance of Up-to-Date Statistics for Teradata SQL Tuning

04/11/202605/02/2023 by Roland Wenzlofsky

1. Complete and up-to-date Statistics At the start of Teradata SQL Tuning, statistics are a vital concern. The Teradata Optimizer employs statistics to formulate the optimal execution plan for our query. The adequacy of statistics or dynamic AMP sampling varies according to the data demographics. To initiate optimization, updated statistics must be provided to the …

Maximizing Performance with Teradata Dynamic AMP Sampling: An Introduction

04/11/202605/02/2023 by Roland Wenzlofsky

Introduction to Teradata Dynamic AMP Sampling Teradata calculates dynamic AMP samples for indexed columns (PI, USI, NUSI) at runtime without requiring statistics. These samples provide key information, including table cardinality and distinct values. They are stored in the FSG cache of each AMP’s table header. This process is referred to as dynamic AMP sampling. A …

Teradata SQL Tuning: How Query Rewriting Can Reduce Runtime from 40 Minutes to Seconds

04/11/202605/02/2023 by Roland Wenzlofsky

It’s time to share a new Teradata SQL tuning case study that showcases the impressive impact of query rewriting on performance. We are studying the query below that originally took 40 minutes to run. As a SQL tuning specialist, I always prioritize adding missing statistics and refreshing stale ones. I analyzed the SQL statement that …