Category Archives for "Performance Tuning"

Oct 26

Rx for Demystifying Index Tuning Decisions – Part 1

By Jeffry Schwartz | Expert , Missing Indexes , Performance Tuning , Query Tuning , SQL Administration , SQL Development , SQL Server

Overview Indices are one of the most troubling and mysterious areas for DBAs and developers. Most understand that adding a badly needed index can yield dramatic query performance improvements, but how does one know what is needed? Many believe more indices are better, regardless of the number. Most fear deleting ANY existing indices, even when […]

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Sep 28

Get Index Column Info with Includes for One or Many Tables

By Lori Brown | Helpful Scripts , Missing Indexes , Performance Tuning , Query Tuning , SQL Administration , SQL Development , SQL Server

I was recently working with one of my clients on some low hanging fruit type of query tuning. We had checked the cache for plans with missing index warnings in them and were trying to see if we could tweak and existing index or add a new index to speed things up. If you ever […]

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Aug 10

How Indexing Affects Deletion Queries

By Jeffry Schwartz | Performance Tuning , SQL Development , SQL Server

The Problem Many articles concerning SQL Server discuss how record insertion overhead increases with each additional index. They discuss b-tree manipulations and page splits in addition to leaf and non-leaf levels. However, few discuss the fact that deletion overhead increases as well, especially when large numbers of records are deleted by individual queries. Recently, I […]

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Jul 20

Handling Multiple Missing Index Recommendations for the Same Table

By Jeffry Schwartz | Expert , Missing Indexes , Performance Tuning , Query Tuning , SQL Development , SQL Server

The Problem Many articles concerning SQL Server missing index recommendations demonstrate the mechanics for obtaining them and often highlight whether the suggested key columns are used in equality or inequality relationships. Most of these examples emphasize a single index that can be implemented to improve performance. However, real-life situations often involve multiple or many suggested […]

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Jun 02

Query Tuning and Missing Index Recommendations

By Jeffry Schwartz | Missing Indexes , Performance Tuning , Query Tuning , SQL Development , SQL Server

Overview Most analysts are familiar with missing index recommendations provided by SQL Server when query plans are displayed within SSMS or reported by various missing index DMVs. Several questions arise concerning these recommendations: What determines whether a column becomes a key or included in the new index? Where does the ordering of the included columns […]

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Apr 13

List Tables That May Be Over Indexed

By Lori Brown | Beginner , Helpful Scripts , Performance Tuning , SQL Administration , SQL Server , Tip of the Month

While not having enough indexes can be bad for query performance, having too many indexes can also be just as bad. Use the query below to get a list of tables in your database that has more than 10 indexes. — Tables with large number of indexes select t.name as TablesWithLargeNumInx, count(i.name) as CountIndexes from […]

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Jan 12

SQL 2016 SP1 USE HINT

By Lori Brown | Intermediate , Performance Tuning , SQL Development , SQL Server , Trace Flags

–By Lori Brown   @SQLSupahStah After installing Service Pack 1 for SQL 2016, I ran across USE HINT and thought I would put out what I could find to document it. Here’s where you find info from Microsoft: https://msdn.microsoft.com/en-us/library/ms181714.aspx and here is a link for all of the bugs that are fixed in SP1: https://support.microsoft.com/en-us/kb/3182545 USE […]

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