That’s not bad enough that you call it SQL whereas your boss pronounces it ‘sequel’. But also, you now suffer from “Super Slow Query Syndrome,” and sometimes, your questions bomb without effect.
Don’t worry. We have your back. We recently had a powwow with a lot of caffeine to think about our favorite tips to fix queries. With the help of this article, we will dig into how we can resolve SQL queries and improve the performance of SQL queries with new tips and tricks, such as action plans, references, wild cards, and much more.
In fact, we have combined all our famous skills into one, so you can increase your SQL intelligence by six minutes flat.
The issues faced by the companies in SQL Server performance often lead to focusing on using tuning tools and development strategies. This will help to analyze and process queries faster and eliminate operational issues, troubleshoot poor performance, avoid any chaos, or reduce the impact on the SQL Server database.
What is SQL Query Optimization?
Optimizing SQL Query is the process of writing considerate SQL queries to improve database performance. During development, the amount of data accessed and tested is not much. Thus, it becomes easy for developers to get a prompt response to their raised questions. But the problem starts when the project becomes live and large data starts to flood the database. These kinds of situations reduce the resolving process and performance.
A request for data or information from a database is called a Query, and you need to write a pre-defined set of code that is understandable to the database. Structured Query Language (SQL) and other query languages recover or manage data from related databases.
There are different formats to write a query in the database, using various algorithms. A query that is incomplete or written poorly can lead to a lot of resource consumption, and also can take a lot of time in execution, which possibly causes a loss in services. A proper query can reduce implementation time and lead to better SQL results.
SQL query optimization’s main purpose is to reduce response time and improve query performance, Reduce CPU performance time for faster results and reduce the number of resources used to improve the output.
Ways to Improve SQL Query Performance
Avoiding unnecessary columns in the SELECT section
To improve MySQL functionality, it’s recommended to specify columns in the SELECT section, instead of using SELECT*. As irrelevant columns create more load in the database, it slows down the performance of the whole system.
Using internal joining, rather than external joining if possible
Use external joining only if necessary. Excessive use of it not only limits database performance but also limits MySQL query options, resulting in slower SQL statements.
Using DISTINCT and UNION only if necessary
By using UNION and DISTINCT operators while there are no major objective results in unwanted filtering and reduced SQL performance. To improve the performance and bring efficiency to the process we can always use UNION ALL, rather than UNION.
Using the ORDER BY clause
To get more clear results it is important to use the ORDER BY clause. It not only brings
advantages for database admins but also increases performance in its execution.
SQL Query Performance Tuning: Best Practice
SQL Query tuning is one of the fastest ways to improve the performance of SQL Server. Set procedures and processes are used to improve the performance and resolve the database-related queries this is called Tuning the SQL server. SQL tuning includes several features, including identifying which queries are slower and utilizing them to work more efficiently. Multiple communication databases like MySQL and SQL Server will benefit from SQL tuning.
The Database Performance Analyzer can attempt to troubleshoot server performance issues in the system. But these measures are expensive, and they may not work to solve the problem of slow-moving queries. Tuning SQL functionality helps you to identify poorly written SQL queries and invalid indexing conditions. After doing so, you may find that you do not need to invest in hardware upgrades or technical details.
Tuning SQL functionality can be difficult, especially if done manually. Believe it or not, the slight changes can have major effects on SQL Server and database performance. Hence, there is a need for practical SQL Query performance tools.
To conclude, generally, the best practices of SQL Query performance Tuning include proper indexing that can be done by the Execution Plan tool in SQL Server. Additionally, avoiding coding loops and correlating SQL subqueries.
Tosska SQL Tuning Expert (TSE™) v4 is one of the best SQL tuning tool available in the market. It helps in tuning the SQL even without any source code.
Stored procedures are increasing in popularity in Oracle Database and SQL Server because of quicker execution. Earlier, application code mostly resided in external programs. However, its shift toward database engine interiors compels database professionals to keep their memory requirements in mind.
This is as necessary as planning for times when the code related to database access will be present within the database. They also need to know how they can handle these stored procedures to maintain ideal database performance. We will look at some of these methods and the advantages of using stored procedures and triggers in the Oracle database.
Perks of Stored Procedures for Oracle Database Performance Tuning
Until recently, a majority of Oracle databases had limited code within their stored procedures. This shift in trends is because of the various advantages that come with placing larger amounts of code, such as the following:
Performance Improvement – Using more stored procedures means you don’t require Oracle database performance tuning as much. That’s because each of these only has to load once into the shared pool. Executing them, therefore, is quicker than running external code.
Code Segregation – The stored procedures have all the SQL codes which turn all the application programs into calls for those procedures. This is an improvement in the data retrieval process because changing databases gets simpler.
Therefore, one advantage you get through stored procedures is the ability to transfer large amounts of SQL code to the data dictionary. Doing this will enable you to perform SQL tuning without involving the application layer.
Group Data Easily – You can gather relational tables with data that shares certain behaviour before looking for Oracle performance tuning tips. Simply use Oracle stored procedures as methods, along with suitable naming conventions. For example, link the behaviour of the table data to the table name in the form of prefixes.
The users may then request the data dictionary to display all the traits connected to one table. This makes it more convenient to recognise and reuse code with the help of stored procedures.
Other Reasons Behind the Increasing Popularity of Stored Procedures
There are plenty of other reasons stored procedures and triggers take less time in comparison with conventional code. One of these has something to do with SGA caching in Oracle database and SQL.
Once the shared pool within the SGA gets a hold of a stored procedure, it keeps it there until the procedure gets paged out from the memory. The SGA mostly does this to create space for other stored procedures. The paging out process takes place based on a Least Recently Used or LRU algorithm.
Two parameters help determine the amount of space that Oracle uses on startup. These are the Cache Size and the Shared Pool Size parameters. They also help users check how much storage space is available for various tasks. These include caching SQL code, data blocks, and stored procedures.
Stored procedures will run extremely fast once you load them into the shared pool’s RAM – as long as you can avoid pool thrashing. This is important because several procedures compete for varying quantities of memory in the shared pool.
The performance of an Oracle database and SQL query speed can directly affect the organisation it belongs to. If the queries running in the database are slow, they will surely have a negative impact. However, its severity may vary based on the database’s role, its architecture, and the industry your organisation operates in.
Regardless of the extent, it would be unwise to ignore them, which is why we are going to talk about all their effects in this blog.
How Slow Statements Affect Oracle Database and SQL Users
In this fast-paced world, everything needs to work fast and offer a quick response time to its end-users. The data that a web page displays generally comes directly from the database with very few interactions.
This implies the dependency of the application’s response time on the time it takes for the queries to run and the database to respond. Slow statements will take more time, resulting in loading screens before the desired information shows up. This is when Oracle database performance tuning becomes a requirement.
Such speeds don’t affect only the application, however; they leave an impact on the other parts of a system as well. The reason behind this is the location of the database in a majority of web architectures.
Take a look at the three-tier architecture, for example – the database lies at the bottom in most cases, forming the foundation. An increase in latency here is likely to cause the same in the higher levels along with other areas in the system.
Another way in which slow queries negatively impact the system is by making the database use more resources than is actually necessary. Some of these are available in limited quantities, such as I/O and CPU, since other applications share these resources.
On the other hand, not using existing resources sufficiently leads to their inefficient usage and slow queries as well. This may be the case with your database, so you may want to consider a few Oracle performance tuning tips that deal with this particular issue.
Top Reasons Behind Slow and Inefficient Queries
Given below are the three most significant causes of queries slowing down:
- Too many tasks: Executing a statement includes multiple tasks, such as retrieving data, making calculations, and arranging data in the order as the query specifies. All of these involve plenty of factors, any of which can increase the amount and complexity of work done, from joining and grouping to filtering and sorting.
- Too much waiting: Sometimes, statements don’t have too much to do, nor are they stuck waiting for resources. The reason why they are sluggish is that they are waiting on other statements that are locking resources or requiring higher levels of activity.
- Too few resources: Query execution works alongside other tasks taking place within a system. This means they share resources such as network throughput, disk I/O, and CPU. Statement execution is likely to take more time when these are completely occupied.
Locating and Working on Slow Queries in Oracle Database
Slow queries don’t get faster on their own – DBAs must take steps to speed them up. For starters, they can use the Database Performance Monitor (DPM) in the following ways:
- Viewing all the queries that are taking up execution time using the query profiler. Such queries are often running in the absence of indexes, so it’s a good idea to add one to improve Oracle database performance and execution speed.
- Automatically collecting explain plans to get a quick glance at the ones that contain information regarding slow queries and the changes related to them, if any.
- Assessing Oracle database and SQL to find out whether a statement can perform better with the help of some improvements.
- Visiting the charts page to go through properly arranged metrics pertaining to system performance. This allows the DBA to set a threshold alert and note changes every time a system resource is reaching maximum use.
Based on your architecture and application, slow statements can affect more aspects of your business than just the database. Therefore, ignoring them is not recommended as it often results in a detrimental impact on both end-users and your organisation.
Consider enlisting the help of professional tuning tools to improve slow query performance in Oracle and SQL Server databases.