THE SQL Server Blog Spot on the Web

Welcome to SQLblog.com - The SQL Server blog spot on the web Sign in | |
in Search

Browse by Tags

All Tags » Query Optimizer   (RSS)
Showing page 1 of 4 (33 total posts)
  • Cardinality Estimation for Disjunctive Predicates in SQL Server 2014

    Introduction Back in January 2014, I wrote an article for SQLperformance.com describing the cardinality estimation process for queries with multiple predicates, from the point of view of the old and new cardinality estimators. The article describes the various behaviours and formulas involved, along with the usual sprinkling of documented and ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on April 15, 2014
  • Incorrect Results Caused By Adding an Index

    It’s not often that a SQL Server bug really surprises me or makes me wonder how it was never spotted before, but this is one of those. To get right into it, say you have the following two tables: CREATE PARTITION FUNCTION PF (integer) AS RANGE RIGHT FOR VALUES (1000, 2000, 3000, 4000, 5000);   ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on August 20, 2013
  • Compute Scalars, Expressions and Execution Plan Performance

    The humble Compute Scalar is one of the least well-understood of the execution plan operators, and usually the last place people look for query performance problems.  It often appears in execution plans with a very low (or even zero) cost, which goes some way to explaining why people ignore it. Some readers will already know that a Compute ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on September 4, 2012
  • Query Optimizer Deep Dive - Part 4

    This is the final part in a series of posts based on the content of the Query Optimizer Deep Dive presentations I have given over the last month or so at the Auckland SQL Users’ Group and the SQL Saturday events in Wellington, New Zealand and Adelaide, Australia. Links to other parts of this series: Part 1 Part 2 Part 3 Beating the Optimizer ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on April 30, 2012
  • Query Optimizer Deep Dive – Part 3

    This is the third part in a series of posts based on the content of the Query Optimizer Deep Dive presentations I have given over the last month or so at the Auckland SQL Users’ Group and the SQL Saturday events in Wellington, New Zealand and Adelaide, Australia. Links to other parts of this series: Part 1 Part 2 Part 4 Storage of Alternative ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on April 29, 2012
  • Query Optimizer Deep Dive – Part 2

    This is the second part in a series of posts based on the content of the Query Optimizer Deep Dive presentations I have given over the last month or so at the Auckland SQL Users’ Group and the SQL Saturday events in Wellington, New Zealand and Adelaide, Australia. Links to other parts of this series: Part 1 Part 3 Part 4 Cost-Based Optimization ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on April 28, 2012
  • Query Optimizer Deep Dive - Part 1

    This is the first in a series of posts based on the content of the Query Optimizer Deep Dive presentations I have given over the last month or so at the Auckland SQL Users’ Group and the SQL Saturday events in Wellington, New Zealand and Adelaide, Australia. Links to other parts of this series: Part 2 Part 3 Part 4 Introduction The motivation ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on April 27, 2012
  • Fun with Aggregates

    There are interesting things to be learned from even the simplest queries.  For example, imagine you are given the task of writing a query to list AdventureWorks product names where the product has at least one entry in the transaction history table, but fewer than ten. One possible query to meet that specification is: SELECT ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on March 11, 2012
  • Query Optimizer Gone Wild - Full-Text

    Overall, SQL Server has become a very capable and mature product, with a very powerful engine and sophisticated query optimizer. Still, every now and then, a certain query structure throws the optimizer for a loop resulting in an execution plan that will take forever. The key to identifying this type of problem begins with the exeuction ...
    Posted to Joe Chang (Weblog) by jchang on February 19, 2012
  • Forcing a Parallel Query Execution Plan

    This post is for SQL Server developers who have experienced the special kind of frustration, which only comes from spending hours trying to convince the query optimizer to generate a parallel execution plan.  This situation often occurs when making an apparently innocuous change to the text of a moderately complex query; a change which ...
    Posted to Paul White: Page Free Space (Weblog) by Paul White on December 22, 2011
1 2 3 4 Next >
Powered by Community Server (Commercial Edition), by Telligent Systems
  Privacy Statement