10 SQL Query Optimization Tips to Improve Database Performance

SQL Database-Performance

Database managers and developers have long been unnerved because their SQL queries are either slow or begin to degenerate after a while. Constant monitoring of such queries is needed to improve the performance of the database management system.

What Makes An SQL Query To Degrade?

An otherwise efficient query might find itself not fulfilling the purpose it was intended for with data growth. Another fact is that even if better queries are written, they might become less useful if they aren’t tested properly. The only answer to both these problems is SQL Query Optimization.

Prerequisites of Optimizing SQL Query –

Before going for Database Optimization targeting the optimization of SQL queries, one should be clear about prerequisites that need to be looked at.

  • It is primarily important to identify the requirements of the business. Some websites fetch search results within split seconds, while some require the customers to finish checking out their cart before a certain time limit. These varying requirements need to be kept in mind.
  • It is i,portant to connect with various teams from testing and development and gather an idea of the issues faced by the end-users.
  • Key information about the database being used is crucial, such as design, indexing approach, and migration of the database. This information creates awareness about any threats that might harm the system while executing SQL queries.

SQL Query Optimization Tips –

The important tips for SQL query optimization are listed below –

  • The foremost thing to do while doing SQL Query Optimization is to make a plan and identify all the queries which are running slow. SQL Query Plans should be made and studied properly to branch out inefficient queries.
  • While searching for strings using the wildcard method, many computations are required because of huge text volumes. Hence it would be more structured to formulate a search based on full text. An index must be created for the searched columns in case a wild card search is inevitable.
  • Before even framing the query, it is important to filter out the optimal requirements. This leads to all the unnecessary data being weeded out beforehand.
  • Select* statements should be usually avoided. This is because on firing a Select query, complete data begins to fetch, deters the performance. Instead of writing a Select* query, it is beneficial to mention the column names explicitly.
  • Select DISTINCT along with the group by clause is a good method of filtering out the distinct outcomes. But this requires a lot of processing power Hence DISTINCT should always be avoided with the SELECT clause, Instead, the more optimal way to do this would be to add more fields in the SELECT statement, which would return unique records.
  • Indexes have long been the most streamlined way of retrieving data from the tables along with boosting performance. It is advisable to use clustered indexes as they don’t occupy space on the disk.
  • It is better to use the EXISTS function rather than the COUNT function. Both these functions help to find whether the record exists in the table. While the COUNT function scans the whole table, the EXISTS function exits processing once it locates the first record.
  • The use of temporary tables is a great tool to manage data seamlessly.
  • Use of loop in a query invariably lowers down performance. It is suggestive to use the INSERT function followed by the UPDATE function.
  • A watchful eye should be kept on the size of the data that is being used. A limited data set will be retrieved faster.