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Statistics

A collection of 51 issues

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

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

Tracking Teradata Statistics Usage with StatUseCountV

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

Maximizing Performance with Teradata Dynamic AMP Sampling: An Introduction

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

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

Understanding Teradata Join Estimation: Heuristics and Importance of Statistics Collection

What is Teradata Join Estimation? This article demonstrates the functioning of Teradata Join Estimation in the absence of statistics. It presents the heuristics employed to estimate row count and emphasizes the importance of collecting statistics on all join columns. Teradata Join Estimation Heuristics The worst-case scenario involves joining two tables

Teradata Statistics Design for High Performance: An Introduction

Learn how Teradata 14.10 simplifies statistics collection for better performance. Discover new features that identify unused and missing statistics.

Teradata Statistics Collection for Improved Query Performance

Learn how to optimize your Teradata queries with statistics collection. Discover what to collect and what to omit for accurate query estimation.

Improving Query Performance with Teradata Statistics Extrapolation and Object Use Counts (OUC)

Optimizing Teradata Queries: From No Index to Hashed NUSI

The initial situation without any index In this blog, I will demonstrate how to optimize a query using Teradata's tools. We will begin with the following test scenario: CREATE TABLE Orders ( OrderId BIGINT NOT NULL, CustomerId BIGINT NOT NULL, Amount BIGINT ) PRIMARY INDEX (OrderId); INSERT INTO Orders SELECT

Building a Teradata Data Warehouse: Considerations for ETL Process, SQL Queries, and Physical Data Model

This post aims to compile all crucial aspects to be considered while constructing a Teradata Data Warehouse, including the ETL process and SQL queries. This list is just the beginning, and I anticipate receiving valuable feedback from my readers to expand it in the future. Initially, I have provided a