The database is a vital part of a majority of IT systems as it contains that data that needs to be processed for utilization. SQL is the standard language for fetching data from the database using queries and query optimization in SQL Server helps maintain database performance.
The queries used to communicate with the database are almost always simple and quick. The most common operations include the four major data manipulation techniques (create, select, update, and delete) that execute at quick rates in most cases. However, as you already know, they aren’t the only tasks an administrator has to do in a database.
Why Experts Recommend Query Optimization in SQL
Operational databases may have a requirement to execute statements that take a long time. For instance, queries that need access to several tables or include tasks such as aggregation.
Although statements that operate on data warehouses aren’t time-critical, the ones running on operational databases are. They are necessary to fetch the requested information as quickly as possible – which makes SQL Server performance tuning important. One of the best examples of systems that need optimal SQL is one that has access to a geo server. A geo server contains millions of geographical information spread across countless tables.
Moreover, the database operations taking place on this data is often performance heavy. Such tasks may include the intersection of lands and calculations of area, the distance between two geographical locations, etc.
These involve complex geo operations that need a large amount of data present in multiple tables. If the SQL statement used for these operations isn’t efficient, it could take days or months to fetch the results. This is where the DBA will need query optimization in SQL Server to ensure the users don’t have to wait too long to get a result.
Some Quick Tips for Maintaining Optimal Database Query Performance
Take a look at some time-tested techniques of optimizing queries in SQL that not only save a lot of time and resources but are also useful for a wide range of databases:
- Check efficiency using LIMIT – Many times, the queries have to run on a huge scale of data. You would not want to wait for your statement to execute completely before finding out that you have used the wrong statement or it was inefficient. Therefore, limiting your statement to a smaller amount of information can help you check its validity and with SQL Server performance tuning. Once you’ve run the query and are satisfied with its efficiency, you can carry it out on the scale you want.
- Long statements can help – At times, you may have written statements that may seem simple to you as they didn’t take long to understand. However, they took too long to actually execute. In databases involving time-critical operations, the opposite would be preferable. Even though the queries will become complex and take a bit longer to understand, they will save a lot of time.
- Give preference to quicker data structures – This depends on the programming-based knowledge of the DBA. For example, integer comparisons are far quicker than string comparisons.
- Don’t be tempted to use IN operator – Checking the existence of certain data in a table may be important. But try not to use the IN operator as it slows down the result.
As mentioned before, these tips are useful for a majority of databases out there. Since SQL is a declarative language, certain databases are likely to optimize for the cases we have talked about above.
However, test the tips before you try to apply them for query optimization in your database. In case some of these don’t work, you may want to consider using a tuning tool to make things easier. Get in touch with us to know how our tuning tool can simplify database query optimization for you.