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SQL Performance Optimization Techniques – Improve Server Queries

SQL performance optimization
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Published By Aswin Vijayan
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Approved By Anuraag Singh
Published On January 11th, 2024
Reading Time 7 Minutes Reading
Category SQL Server

We must admit that SQL performance optimization is quite significant for all SQL developers & architects from time to time. To manage a database a query language is a must to communicate & exchange information with a database. SQL is one of the finest & most popular languages for databases. It is even the base for other database languages.

However, with changing times, there are a lot of technical changes that users must adhere to. SQL performance improvement techniques are essential for maintaining a healthy database with fast-running queries. Let’s make sure we have a server without any issues by following the below-mentioned optimization techniques.

Know SQL Queries for SQL Performance Improvement Techniques

Before we move towards the technique we must understand what are queries in real. This can clear a lot of doubts in the beginning only.

What is an SQL Query?

We all know SQL as Structured Query Language but it’s not straight. It came to highlight in the 1970s with the name Structured English Query Language (SEQUEL). However, due to trademark issues, it later changed the name to SQL. Now users may call this either Standard Query Language or Structured Query Language, both are fine.

Now, Queries are the command that a user gives to the system in order to make it perform any desired action. Users need to be aware of the SQL performance optimization techniques for better database working. There are several different tasks that a database can do & for that, we need a command that we call queries in SQL. With time, these queries come up with advanced alternations.

Select Queries for SQL Performance Optimization

Before we optimize queries for better working, we need to understand what queries need to be optimized. Let’s have a look at the below key points to know this factor in depth.

Queries Taking Majority of Execution Time

It’s important that users focus on the queries that take more execution time. For example, if a query takes more than 5% of your total execution time, simply focus on optimizing that.

Queries that are Consistently Slow
It’s crucial for users to optimize queries that are slow throughout the process. Queries with frequent execution, the higher latency in them can cause unpleasant server performance.

Queries that are Occasionally Slow
Now, if you have a query that’s occasionally slow, you just need to find out the average run time for that. Optimizing such queries is not a priority but SQL performance improvement techniques suggest optimizing them as well.

Queries with a Red Flag on Them
If there are not any performance issues, still you might need to optimize queries before it gets too late. If you have any queries that returned warnings as well as errors, schedule optimizing these queries first.

SQL Performance Optimization Best Practices For Users

There are majorly three tips here that users need to follow. And to be very honest, even new users can follow these three tips. It can help users get the perfect results as expected. Now as we know which queries we need to optimize, now there’s no time to waste.

Requirement Analysis
Whenever we try to get any specific data, we need to execute a particularly related query. To find the right is, simply define the data that you need to retrieve. Being aware of the requirements is necessary before the execution of queries. This can result in getting the only results that optimize queries & which I need.

Table Size Reduction
Optimizing the table is a significantly major part of the SQL database. Large tables often cause performance issues for users. Filter your data for getting selective results always. This will help you reduce your table size as well. To optimize tables of SQL server & improve the speed of your queries, simply follow these techniques:

  • Limit the range of dates for time series data.
  • Limit the subquery dataset as well.
  • Avoid the data with duplicacy.

Simplify the Joins

SQL performance optimization techniques require users to simplify joins. A query joining the table increases the result set’s row count drastically. You already know the methods of reducing table sizes in the above key point.

Be aware of the fact that in some cases, even small changes can have good & big results. Changing the order of tables while joining them helps users a lot. 

A Quick Tip: While joining two tables, simply start with the one that returns fewer results after the filtration task.

Use Alternative Queries For Faster & Better Results

Using alternate queries is one of the important  SQL performance improvement techniques.

Add EXPLAIN in the Beginning

It’s good to view your query execution plan. Therefore, adding EXPLAIN in the beginning help users to get that plan. Don’t rely on it always as it’s not always accurate. However, it gives an idea to the users.

That way, users can locate & modify the steps that are expensive in nature. This saves a lot of time & effort for users.

SELECT Fields FROM is better than SELECT * FROM

SELECT Fields FROM query is better as it nails down the data fetched from any given table while running a query. Hence, it increases the speed.

SELECT DISTINCT takes a lot of processing power. This is why using the SELECT ID is a lot more efficient for users.

This small difference is a lot when it is followed on a daily basis by users. This way, users reduce unnecessary data searching as well as power consumption.

Using WHERE in place of HAVING is better

WHERE queries run faster than the HAVING queries The reason is that WHERE queries filter the data transactions & records before the creation of groups. However, HAVING query filters records from the groups themselves. Optimizing this query is quite easy & has better results for SQL performance optimization objectives.

COUNT() is not the better one, Use EXISTS()

Using both COUNT() & EXISTS() is fine. However, EXISTS() is effective as it runs only till it finds the first entry of the desired record in the table. It saves significant time & power for other computing tasks & queries.

On the other hand, COUNT() will search the entire table & then provide the total number of matching records to users. This takes more time & makes the process slow.

SQL Performance Improvement Techniques – Precautions

Create & Manage Indexes

It’s important for users to create & manage indexes. It helps in quick data searching & results retrieval. Always make sure that your indexes are not fragmented & perform Index rebuild tasks for that too.

Beware of Corruption Issues

Database corruption issues are the most critical ones. Users must know that the DBCC CHECKDB command is quite useful for checking corruption & Repair_Rebuild, Repair_Fast  can help users. Users can also check out the 5 Best SQL Recovery Tools that help them repair corruption faster & easily.

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Avoid Running Queries in Loop

Loop running of queries also slows the runtime Bulk inserting & updating data is way better than using the loops. It’s more efficient as well as equally effective.

Migrate to A Latest Version

In case, users want to change the server, they can switch to the latest SQL Server for unmatched performance. This optimized performance can be really helpful for users in many cases. Moreover, users can get this all by choosing any of the top 5 SQL Server Migration Tools for the process.

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In A Nutshell

Finally, we can say that we know the SQL performance optimization methods very well. Yes, this isn’t rocket science. Users with decent technical knowledge of SQL servers can optimize their performance.

The most crucial aspect for users is to select the queries that require optimization & protecting the database from corruption. Apart from that, it’s easy as well as fun and informative to use these SQL performance improvement techniques for good. We hope you will wisely execute your queries from now.