Database performance tuning allows developers or DBAs to maximize system resources for lasting performance improvements.
Databases are like the central nervous system of an application in that they're responsible for the organization and function of critical processes. Consequently, even relatively minor database-related performance issues have the ability to impact the entire operation.
Locating database issues in time can help applications stay healthy and accessible. Without comprehensive monitoring in place, database outages can go unnoticed until it’s too late resulting in the business losing revenue and customers.
Ensuring that the host of your database processes has sufficient resources is an essential step to solving performance issues. Start with a check-up of your CPU, memory, and disk space to help identify potential problems.
If your database routinely underperforms, it may be necessary to upgrade to a higher class CPU unit. Evaluate the various aspects of CPU performance, such as CPU ready times, which can alert you to instances that your system was unable to use the CPU due to insufficient resources. Due to the continuous base load database servers induce, a minimum of two CPU cores may be necessary to keep the server responsive. Upgrading to a more powerful CPU can reduce the strain introduced by multiple applications and requests, improving database speed and efficiency.
A lack of available memory is another potential culprit of database performance problems. An effective evaluation of your memory needs involves assessing two different metrics: memory usage and page faults per second. A page faults number in the thousands signals that your hosts are running out of available memory space, and an increase is necessary. Having more available memory can improve the efficiency and performance of the system.
Increasing the amount of memory used by MySQL to allocate 70 percent of the total memory is another option, as long as the database is the only application on that server.
Having a lot of storage available for your database server is crucial due to the fact that indexes and other performance improvements cause databases to consume more disk space than is actually necessary. Running your database on its own hard drives can minimize the disk fragmentation that occurs as a result of other processes. Also, dedicating a set of drives for data files, log files, backup files, and tempdb not only improves performance, but also serves as a convenient back-up in the event of a recovery disaster.
A prevalent issue that results in decreased database performance is an increase in disk latency. Monitor metrics related to disk latency closely. The quickest and most cost effective way to mitigate latency issues involves utilizing the caching mechanisms available to you.
The type of disks in your server is another important factor in improving performance. The amount of data the query needs to access or return can require millions of i/o operations for simply retrieving the results of even a single query. Upgrading to solid-state disks can impact the performance of your SQL queries, which can result in better performance from your database. Choose an SSD model designed for database usage for optimal results.
Although it's often overlooked during development, indexing can optimize query execution and improve database performance. A strategic set-up of your indexes can organize data structures in a way that facilitates more efficient data retrieval and improves response time.
Research best practices for structuring queries in order to optimize indexing strategies and improve performance.
Performance bottlenecks can be the result of a single application or service that has access to your database. If one of the individual clients is suffering from performance issues, evaluate that service's metrics to try to pinpoint the problem.
A single service could be the cause of performance problems for your entire operation, however, if all of your database's clients are experiencing issues, the health of your host may be the actual problem. In that case, reevaluate your hardware to identify if it could be the culprit of your database performance problems.
If connection acquisition absorbs a large portion of your database's response time, you may need to reconfigure your connection pool. Correctly configuring a connection pool involves knowing how many connections your database can realistically accommodate.
Determine capacity by monitoring your server's metrics as you gradually increase the load and number of connections until your CPU, memory, or disk performance reaches its limit. If you still require additional connections, a hardware upgrade may be necessary to meet the needs of your application.
Many performance issues are related to query performance. Although using a sub query can make coding more convenient, it can also hinder database performance.
Coding loops can also contribute to thousands of unnecessary requests which may weight down your database. Avoid adding cursors, which are used for looping in SQL servers, in favor of SQL statements whenever possible.
Streamline your coding for maximum efficiency by using a query optimizer to help guide coding choices to improve SQL query performance and overall database performance.