Performance

Esat Erkec
Comparison of the Merge Join vs Hash Match Join

Query Optimization Myths

March 23, 2021 by

In this article, we will talk about two query optimization myths and these myths can be changed according to the characteristics of the queries. Every query can exhibit different behaviors according to data distribution, SQL Server version, database settings, and other tons of parameters therefore the fixed ideas may not help to overcome the query performance issues. In the next part of the article, we will focus on the following most known discourse:

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Esat Erkec
How we can read a query plan

How to read an execution plan with all details

January 28, 2021 by

In this article, we will discuss how to read the SQL Server execution plan (query plan) with all aspects through an example, so we will gain some practical experience that helps to solve query performance issues. Interpreting query plans correctly is the first and major principle to troubleshoot query performance issues. When we try to find an answer to the “why is this query running slow?” question, the best starting point would be to analyze the query plan.

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Esat Erkec
Trivial query plans and contradiction detection

Explore the secrets of SQL Server execution plans

December 10, 2020 by

The SQL Server execution plan (query plan) is a set of instructions that describes which process steps are performed while a query is executed by the database engine. The query plans are generated by the query optimizer and its essential goal is to generate the most efficient (optimum) and economical query plan. Some query plans that are created by the query optimizer contain some interesting characteristics. In this article, we will go into details of these interesting query plans.

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Esat Erkec
Detecting the tempdb database spills with extended events

Explore secrets of the SQL Server tempdb database

October 29, 2020 by

In this article, we will uncover some secrets about the SQL Server tempdb database. Tempdb is a system database and it is used for various internal and user operations. Besides this, the tempdb has many unique characteristics, unlike the other databases. When we take into account all of these features of the tempdb, there is no doubt that it is an essential part of the SQL Server.

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Esat Erkec
Tune SQL Server performance using with help of the wait statistics

Boost SQL Server Performance with Wait Statistics

October 26, 2020 by

In this article, we will explore, how we can increase SQL Server performance with the help of the wait statistics. Wait statistics are one of the most important indicators to identify performance issues in SQL Server. When we want to troubleshoot any performance issue, at first we need to diagnose the problem correctly because correctly diagnosing problems help with half of the solution. Now, let’s learn wait statistics which helps to identify performance issues properly.

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Esat Erkec

SQL Server Clustered Indexes internals with examples

October 14, 2020 by

In this article, we will learn the SQL Server clustered index concept and some internal details. Indexes are the database objects that accelerate the performance of data accessing when are designed properly. A clustered index is one of the main index types in SQL Server and the working principle is a bit complicated but in the next sections of this article, we are going to simply learn the clustered index working principle and uncover the secrets.

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Esat Erkec
Set the test scenario query

Performing a Load Test on SQL Server using Apache JMeter

October 7, 2020 by

In this article, we will learn how to use Apache JMeter to perform a load test on SQL Server. This test type enables us to measure the application behaviors under specific conditions so that it enables us to observe a variety of resource consumptions (CPU, memory, latency, response times, etc) and it also helps to detect the performance bottlenecks. Database testing can help to find out and identify the problem when the database working under high workloads with multiple users. The database people can identify and fix the performance issues before publishing the database into the production through these tests.

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Esat Erkec
Read I/O and Write I/O sections of the performance test

Using Diskspd to test SQL Server Storage Subsystems

July 28, 2020 by

In this article, we will learn how to test our storage subsystems performance using Diskspd. The storage subsystem is one of the key performance factors for SQL Server because SQL Server storage engine stores database objects, tables, and indexes on the physical files. Therefore, the storage engine always interacts with the disk subsystem because of data processing. In this context, when a bottleneck occurs on the storage subsystems, it causes a negative impact on SQL Server performance. It would be the right approach to measure the performance of the disks to be used before the SQL Server installation based on their usage purposes. For example, OLTP databases have to complete delete, insert, and update processes in a short time but OLAP databases handle a huge amount of batch data. In this case, the storage requirement of these two database systems should differ from each other. In short, it is a best practice to test and analyze the performance of the storage subsystems according to their usage purposes so that we can eliminate the I/O problems in advance.

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