Introduction to SQL Performance Tuning
- Using Indexes for Large Tables. Indexing is a very efficient method to performance tune our database servers. ...
- Reducing Table Size. ...
- Limit the Number of Rows. ...
- Use Temporary Tables. ...
- Using Joins Wisely. ...
- Use Explain and Explain Analyze Keywords. ...
- Conclusion. ...
- Recommended Articles. ...
How to performance tune your SQL Server?
- Using an SQL monitoring tool to monitor performance
- Improving indexes
- SQL Server deadlocks
- Reducing query runtime
How to debug and tune the performance of SQL queries?
What you'll learn
- Identify poorly performing SQL
- Understand how the Query Optimizer makes decisions about how to access data
- Define how optimizer statistics affect the performance of SQL
- List the possible methods of accessing data, including different join methods
- Modify a SQL statement to perform at its best
How to improve Microsoft SQL Server performance?
- First we need to find out which operators take most of the query cost.
- If the operator is taking a lot of cost, we need to learn the reason why. Most of the time, scans will take up more cost than seeks. ...
- There are approximately 78 operators, which represent the various actions and decisions of the SQL Server execution plan. ...
What is improve SQL query performance?
SQL Server Optimization Best Practices
- Choose SELECT Fields Over SELECT *. ...
- Avoid SELECT DISTINCT Statements. ...
- Define Filters With WHERE Instead of HAVING. ...
- Keep Wildcards at the End of Phrases. ...
- Use LIMIT to Sample Query Results. ...
- Use INNER JOIN Rather Than WHERE for Joins. ...
What is performance tuning SQL Server?
SQL Server performance tuning encompasses a set of processes and procedures designed to optimize relational database queries, so they can run as efficiently as possible. SQL tuning involves several elements, including identifying which queries are experiencing slowdowns and optimizing them for maximum efficiency.
How is performance tuning done in SQL?
In a nutshell, SQL performance tuning consists of making queries of a relation database run as fast as possible. As you'll see in this post, SQL performance tuning is not a single tool or technique. Rather, it's a set of practices that makes uses of a wide array of techniques, tools, and processes.
What is database performance tuning?
Database performance tuning is a broad term referring to the ways database administrators can ensure databases are running as efficiently as possible. DBMS tuning typically refers to tuning queries for popular database management systems like MySQL or Oracle.
What is meant by SQL tuning?
SQL tuning is the iterative process of improving SQL statement performance to meet specific, measurable, and achievable goals. SQL tuning implies fixing problems in deployed applications. In contrast, application design sets the security and performance goals before deploying an application.
How do I make MySQL query run faster?
Below are 23 rules to make your SQL faster and more efficientBatch data deletion and updates. ... Use automatic partitioning SQL server features. ... Convert scalar functions into table-valued functions. ... Instead of UPDATE, use CASE. ... Reduce nested views to reduce lags. ... Data pre-staging. ... Use temp tables. ... Avoid using re-use code.More items...
How is SQL query performance measured?
Use the Query Store page in SQL Server Management StudioIn Object Explorer, right-click a database, and then select Properties. Requires at least version 16 of Management Studio.In the Database Properties dialog box, select the Query Store page.In the Operation Mode (Requested) box, select Read Write.
Why do we do performance tuning?
Performance tuning lets you build indexes and eliminate problems which could cause your data retrieval to be slower than it has to be. Nothing frustrates your team of employees more than waiting for the database to conduct its searches. That will lead to more frustration reaching your customers or clients.
How can SQL Server improve SQL performance?
Tips to improve SQL Server performance & database designChoose Appropriate Data Type. ... Avoid nchar and nvarchar. ... Avoid NULL in the fixed-length field. ... Avoid * in SELECT statement. ... Use EXISTS instead of IN. ... Avoid Having Clause. ... Create Clustered and Non-Clustered Indexes. ... Keep clustered index small.More items...•
How to make a database run faster?
A database is a piece of software that runs on a computer, and is subject to the same limitations as all software—it can only process as much information as its hardware is capable of handling. The way to make a query run faster is to reduce the number of calculations that the software (and therefore hardware) must perform. To do this, you'll need some understanding of how SQL actually makes calculations. First, let's address some of the high-level things that will affect the number of calculations you need to make, and therefore your querys runtime: 1 Table size: If your query hits one or more tables with millions of rows or more, it could affect performance. 2 Joins: If your query joins two tables in a way that substantially increases the row count of the result set, your query is likely to be slow. There's an example of this in the subqueries lesson. 3 Aggregations: Combining multiple rows to produce a result requires more computation than simply retrieving those rows.
How does a database work?
A database is a piece of software that runs on a computer, and is subject to the same limitations as all software—it can only process as much information as its hardware is capable of handling . The way to make a query run faster is to reduce the number of calculations that the software (and therefore hardware) must perform.
What is the lesson on subqueries?
The lesson on subqueries introduced the idea that you can sometimes create the same desired result set with a faster-running query. In this lesson, you'll learn to identify when your queries can be improved, and how to improve them.
When working with subqueries, should you make sure to limit the amount of data you're working with in the
In general, when working with subqueries, you should make sure to limit the amount of data you're working with in the place where it will be executed first. This means putting the LIMIT in the subquery, not the outer query. Again, this is for making the query run fast so that you can test— NOT for producing good results.
Is a query runtime dependent on a database?
Query runtime is also dependent on some things that you can't really control related to the database itself: Other users running queries: The more queries running concurrently on a database, the more the database must process at a given time and the slower everything will run.
How to diagnose slow queries?
In order to diagnose slow queries, it’s crucial to be able to generate graphical execution plans, which you can do by using SQL Server Management Studio. Actual execution plans are generated after the queries run.
What is APM in SQL?
One of the great features of application performance management (APM) tools is the ability to track SQL queries. For example, Retrace tracks SQL queries across multiple database providers, including SQL Server. Retrace tells you how many times a query was executed, how long it takes on average, and what transactions called it.
Is SQL performance tuning important?
Some programmers, on the other hand, believe that even though SQL performance tuning is important, only DBAs should do it.
Can you use more than one SQL Server performance tuning tool?
Next time you need to do some performance tuning with SQL Server, you’ll have a few options at your disposal to consider. Odds are that you’ll use more than one of these tools depending on what you are trying to accomplish.
Is SQL Server Profiler deprecated?
It was a very useful tool to see in real-time what SQL queries are being executed against your database, but it’s currently deprecated. Microsoft replaced it with SQL Server Extended Events.
What is SQL performance tuning?
SQL performance tuning means you have to see the forest and the trees. You can’t work on your queries without keeping the tables and indexes in mind. Here’s the tip: After you’ve sorted out the tables and indexes, zoom out to consider all essential queries.
What time can you run a monster query?
When you have a monster query and there’s no way to streamline it, ask if you can run it during off-peak hours—usually between 3 and 5 a.m.— or over the weekend.
Why is database maintenance important?
Database maintenance is essential to SQL tuning because this task enables you to find potential issues and solve problems you may have never known existed. Maintenance tasks may vary by environment, but there are some common or general tasks that are recommended.
Is it hard to decide where to start with database performance tuning?
When presented with the task of database performance tuning, it can be hard to decide where to start. You may not yet have an idea of what aspect of your database requires attention. When talking about administering a database in the cloud, you may have to bring into consideration things you didn’t have to worry so much about when your database was on-premises.
Monitoring and tuning databases for performance
Microsoft SQL Server and the Microsoft Windows operating system provide utilities to view the current condition of the database and track performance as conditions change. There are a variety of tools and techniques you can use to monitor Microsoft SQL Server. Monitoring SQL Server helps you:
Monitoring in a dynamic environment
Changing conditions result in changing performance. In your evaluations, you can see performance changes as the number of users increases, user access and connection methods change, database contents grow, client applications change, data in the applications changes, queries become more complex, and network traffic rises.
Choosing a Monitoring Tool
The choice of a monitoring tool depends on the event or activity to be monitored.
Windows Monitoring Tools
Windows operating systems and Windows Server 2003 also provide these monitoring tools.
What is SQL tuning?
SQL tuning commonly involves finding more efficient ways to process the same workload. It is possible to change the execution plan of the statement without altering the functionality to reduce the resource consumption.
Why is SQL tuning automated?
Because the manual SQL tuning process poses many challenges to the application developer, the SQL tuning process has been automated by the automatic SQL Tuning manageability features. Theses features have been designed to work equally well for OLTP and Data Warehouse type applications. See Chapter 12, "Automatic SQL Tuning".
What is query optimizer?
The query optimizer uses statistics gathered on tables and indexes when determining the optimal execution plan. If these statistics have not been gathered, or if the statistics are no longer representative of the data stored within the database, then the optimizer does not have sufficient information to generate the best plan.
What is a hints in SQL?
You can use hints in SQL statements to instruct the optimizer about how the statement should be executed.
What is Oracle Enterprise Manager?
Oracle Enterprise Manager provides tools for identifying resource intensive SQL statements, generating explain plans, and evaluating SQL performance.
When tuning (or writing) a SQL statement in an OLTP environment, the goal is to drive from the
When tuning (or writing) a SQL statement in an OLTP environment, the goal is to drive from the table that has the most selective filter. This means that there are fewer rows passed to the next step. If the next step is a join, then this means that fewer rows are joined. Check to see whether the access paths are optimal.
What is high load SQL?
High-load SQL are poorly-performing, resource-intensive SQL statements that impact the performance of the Oracle database. High-load SQL statements can be identified by:
