What do you do if your database performance is suffering?

To make the best effort to check the symptoms, we can divide the scope of work into three areas. Check the database, operating system and application and by type of signs the appropriate area. For example, for a poor I/O, we should first check the operating system level for I/O statistics. For a weak query, we need to check the database for any plan changes and otherwise visit the application side for any changes.

1. Run the sp_who2 or any similar command to Identify Performance Bottlenecks. 2. Identify and optimize poorly performing queries by analyzing query execution plans, identifying long-running or resource-intensive queries. 3. Rewrite queries to use efficient join methods, reduce unnecessary data retrieval, and minimize resource consumption. 4. Tune Database Configuration like memory allocation, buffer cache size, and parallelism settings. 5. Consider tuning database parameters related to query optimization, locking, and concurrency control to improve performance. 6. Optimize Data Storage and Access. 7. Scale Up or Scale Out. 8. Review Application Design. 9. Monitor and Tune Regularly.

If your database performance is suffering, there are several steps you can take to diagnose and address the issues: * Identify Bottlenecks: * Optimize Queries: * Optimize Indexing: * Tune Database Configuration: * Upgrade Hardware: * Optimize Schema Design: * Implement Caching Mechanisms: * Upgrade Database Software: * Monitor and Tune Regularly: * Consider Database Optimization Tools: Explore database optimization tools and utilities that can automate performance tuning, query optimization, and index management tasks. Use database management and monitoring platforms that provide comprehensive performance analysis and diagnostic capabilities to streamline optimization efforts.

-Review Configuration: Examine SQL Server configuration settings. Look for any recent changes or anomalies. -Check Memory Allocation: Ensure that memory allocation is appropriately configured. Incorrect settings can impact performance. -Monitor Resource Usage: Use tools like Performance Monitor or SQL Server Management Studio (SSMS) to track CPU, memory, disk, and network usage. -Inspect Error Logs: Check SQL Server error logs. Look for critical errors, warnings, or unusual events. -Event Viewer: Examine the Windows Event Viewer for system-level errors related to SQL Server. -Health Check: Verify the health of SQL Server Agent jobs. Ensure they are running as expected. -Failed Jobs: Investigate any failed jobs.

You can split the performance issue into one of two camps: Running or Waiting. The troubleshooting approach is different depending on which one of these it is. To determine, look at the query and see if the CPU is spinning on it or if it is waiting on something. Also, if a query is 'running slow' you need to know what 'normal' is. How long did it take to run previously, when everything was acceptable? When was that? What has changed since then?

When a query is waiting on something, you need to pick the top wait. Most of the time anything less than a thousand milliseconds is acceptable. There are many different types of waits. Here are some high-level things you can do: 1. Make sure your statistics are nice and fresh. 2. Make sure nothing else running on your SQL Server competing for resources. 3. Makes sure your antivirus exceptions in place. 4. Turn off all tracing. 5. Check the errorlog & ensure SQL using all the available CPU in the system. 6. Run the query directly from SSMS. If it is fast, then check everything else: the application server, your network, etc. This is high level and will not cover all possible scenarios. SQL performance is an 'it depends' answer.

Just because you resolve the top waiting query doesn't necessarily mean that you have resolved the issue. Very often it is a multitude of things that has cause SQL to not perform well. If performance is still suffering, then you repeat the process until the response time is acceptable. Think of it like the layers of an onion, peeling away the layers until the issue is resolved.

How many stories would you like? I once had a case where only the UDF were slow. Turned out to be monitoring software. 99% of the time, Ola's scripts are fantastic at keeping a database happy, but I've seen a couple of customers where it wasn't sufficient and we had to update stats for the whole table, and do it multiple times a day, for SQL to run well (poor design, really). I've seen folks migrate from physical hardware to "beefier" virtual machines and SQL run much slower. I've seen folks migrate from one VM to another and the customer swear up and down the new VM was "identical" to the old one...it wasn't.