Performance

Prashanth Jayaram

Top 8 new (or enhanced) SQL Server 2017 DMVs and DMFs for DBAs

January 17, 2018 by

Dynamic management views (DMVs) and dynamic management functions (DMFs) are system views and system functions that return metadata of the system state. On querying the related system objects, database administrators can understand the internals of SQL Server. It allows us to monitor the performance of the SQL Server instance, and diagnose issues with it.

SQL Server 2017 ships with a number of new and enhanced dynamic management views and dynamic management functions that will help DBAs monitor the health and performance of SQL Server instances. A few existing DMV’s such as sys.dm_os_sys_info and sys.dm_db_file_space_usage have been enhanced. Some have also been newly built and available only for SQL Server 2017.

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Esat Erkec

How to use sargable expressions in T-SQL queries; performance advantages and examples

December 22, 2017 by

The challenge

One of the main tasks of a SQL Server database administrator is performance tuning. Sometimes, though, coders or developers don’t always prioritize database performance or query optimization. Here is a typical scenario

  • Imagine that developers create a new table and then insert some records in a test environment and test their queries to retrieve data from it
  • The query executed successfully and does not exhibit any symptoms of performance problems
  • The developer team release this table and query into production
  • One day you take a telephone from your colleague and he says my report is very slow
  • Bingo! In production, this table contains a lot of records and this is resulting in performance bottlenecks when querying it
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Ahmad Yaseen

SQL Server read-ahead mechanism; concept and performance gains

December 21, 2017 by

The user’s read requests in SQL Server are managed and controlled by the SQL Server Relational Engine, that is responsible for determining the most optimized access method, such as index scan or table scan, to retrieve the requested data. These read requests are also optimized internally by the SQL Server Storage Engine, the buffer manager components specifically, that is responsible for determining the general read pattern to be performed.

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Ahmad Yaseen

SQL Server Data Type Conversion Methods and performance comparison

October 3, 2017 by

When you define SQL Server database tables, local variables, expressions or parameters, you should specify what kind of data will be stored in those objects, such as text data, numbers, money or dates. This attribute is called the Data Type. SQL Server provides us with a big library of system data types that define all types of data that can be used with SQL Server, from which we can choose the data type that is suitable for the data we will store in that object. You can also define your own customized user defined data type using T-SQL script. SQL Server data types can be categorized into seven main categories:

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Kaloyan Kosev

Performance tuning for Azure SQL Databases

July 21, 2017 by

With the latest versions of Azure SQL database, Microsoft has introduced a number of new mechanisms to help users and administrators better optimize their workload.

Automatic index management and Adaptive query processing provide us with the possibility to rely on the built-in intelligence mechanism that can automatically tune and improve the performance of our workload.

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Neeraj Prasad Sharma
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SQL Server TOP clause performance problem with parallelism

April 13, 2017 by

Basics of TOP Operator

The TOP keyword in SQL Server is a non-ANSI standard expression to limit query results to some set of pre-specified rows. As an argument, it takes 0 to positive Bigint (9223372036854775807) and anything beyond or less gives an error message. TOP without an order by clause, in production, seems buggy because it can produce results in any order depending on the current schema and execution plan. You can also specify a percent with TOP expression which returns only the expression percent of rows from the result set. Float expressions used in TOP percent are rounded up to the next integer value.

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Koen Verbeeck

How to optimize the dimension security performance using partitioning in SSAS Multidimensional

March 27, 2017 by

Introduction

In the articles How to partition an SSAS Cube in Analysis Services Multidimensional and Benefits of Partitioning an SSAS Multidimensional Cube, the concept of measure group partitioning is introduced and the advantages are clearly illustrated. One of the biggest advantages of partitioning is partition elimination, where only the partitions necessary to satisfy the query are read instead of all the data.

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Mustafa EL-Masry

How to analyze Storage Subsystem Performance in SQL Server

February 23, 2017 by

Introduction

To improve performance, it is common for DBAs to search in each aspect except analyzing storage subsystem performance even though in many times, issues are, in fact, caused by poor storage subsystem performance. Therefore, I want to give you some tools and recommendation that you can use it to prevent your storage subsystem from being a performance issue for you.

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Ahmad Yaseen

Indexing SQL Server Temporary Tables

January 31, 2017 by

SQL Server Temporary tables are a special type of tables that are written to the TempDB database and act like regular tables, providing a suitable workplace for intermediate data processing before saving the result to a regular table, as it can live only for the age of the database connection.

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Ed Pollack

SQL Server Job Performance – Reporting

January 19, 2017 by

Description

Once collected, job performance metrics can be used for a variety of reporting needs, from locating jobs that are not performing well to finding optimal release windows, scheduling maintenance, or trending over time. These techniques allow us to maintain insight into parts of SQL Server that are often not monitored enough and prevent job-related emergencies before they become emergencies.

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David Alcock

Using sp_server_diagnostics

January 19, 2017 by

Troubleshooting SQL Server is all about gathering the right evidence. Ordinarily we utilise a variety of different methods and analyse their output to look for specific areas where we would focus our diagnostic efforts. We could for example, use the results of various DMVs to look at wait statistic and resource information to help us focus our investigation in a particular area of SQL Server.

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Ed Pollack

SQL Server Job Performance – Tracking

January 19, 2017 by

Description

Keeping track of our SQL Server Agent jobs is a very effective way to control scheduling, failures, and understand when undesired conditions may be manifesting themselves. This is a brief journey towards a solution that provides us far greater insight into our jobs, schedules, and executions than we can glean from SQL Server by default.

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Kimberly Killian

SQL Server Index vs Statistics a consultants woes…or rants

December 29, 2016 by

As a DBA, I am often asked why is something performing slow, what and why statistics need to be updated or what will cause them to be “off”. My initial question to clients when they pose these questions to me is what changed on your end? Did the data change significantly and did the rebuild or reorganize index job run? Before I get into the answers to these questions from my clients, let me give you some background. So, just to clarify, for most of my clients, I work as a remote part-time DBA, that being said, I manage their database from every aspect including setting up servers, backups/restore, troubleshooting, managing their index’s, etc. and again remotely. So normally, I have setup jobs that will manage their index’s ranging from a weekly rebuild or even sometimes I use one that I’ve designed that makes a choice to either rebuild or reorganize an index based on fragmentation level. The “general rule of thumb” is reorganizing the index for fragmentation from 5% to 29% and rebuild when 30% plus. Those are pretty standard numbers I did not make them up.

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Daniel Calbimonte

SQL Server performance myth busters

December 21, 2016 by

Introduction

In this article, we will verify if the following statements are true or they are just myths:

  1. Truncate is faster than a delete and it consumes less space in the logs
  2. Do not use cursors to Create or drop multiple objects because it is very slow
  3. Do not use cursors to convert or process row values because it is very slow
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Sifiso W. Ndlovu

Top 5 New SQL Server 2016 DMVs for DBAs

December 20, 2016 by

Since its initial release that was part of SQL Server 2005, Dynamic Management Views (DMV) changed – mostly for the better – the role of database administration (DBA) within SQL Server-based environments. They improved the efficiency of DBAs regarding database server monitoring, issue diagnoses, and subsequent performance optimisation. As a result of this positive reception, it has become customary that some of the highly anticipated items in every release of SQL Server includes discovering what new DMVs will be added. In this article I take you through my favourite top 5 DMVs to come out of SQL Server 2016.

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Daniel Calbimonte

3 ways to improve T-SQL performance

November 22, 2016 by

Introduction

When customers used to ask for advice to solve some T-SQL Problem, they would show me their scripts, stored procedures and cursors. I saw horrible things doing that job, some things I do not want to remember, and even some I cannot tell you about 😉 In this article, we will talk about performance problems when using while loops in T-SQL. We will also talk about problems with UNIONsand finally the use of JOINS of two or more tables using the where clause (ANSI 89) instead of using INNER, LEFT or RIGHT JOINS using the from clause (ANSI 92).

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