Preserving optimal database performance is important for lots of reasons, and sluggishness can be costly, frustrating and tricky to troubleshoot if problems are left unchecked.
The good news is that with a few straightforward checks, and regular maintenance, any SQL server setup can run smoothly from day to day.
For administrators that need a helping hand, the following tactics will assist with optimization efforts and let you sidestep common database performance pitfalls.
Look Into Index Fragmentation
Indexing is a very useful feature of an SQL database, as it allows you to find information quickly without necessarily having to scour every single last entry in a given table.
However, the way that indexing is handled means that over time, fragmentation is inevitable. And the more fragmentation that occurs, the longer it will take queries to be processed.
When it comes to resolving index fragmentation, you can either instigate the defragmentation process manually, or use a modern database management tool to automate it instead.
Be aware that when indexes are being rebuilt, server performance will also suffer, so schedule this so that it does not coincide with peak periods of usage, or else you could cause more consternation.
Scrutinize Wait Statistics
Wait stats are a catch-all starting point for your SQL server troubleshooting efforts, since they can demonstrate that performance imperfections are present in the first place, and inform you of your next steps.
These stats indicate which threads are waiting and how long they have to wait before they can gain access to the resources they need to execute successfully.
There are in fact different wait types to take into account, and with these details to hand you can work out whether a problem is present, and where to look to fix it.
This is where the likes of locking, blocking and deadlocking come into play. You will usually need to work on problematic queries to ensure that they are not being overzealous with how they use system resources, and wait stats will leave the trail of breadcrumbs for administrators to follow in this instance.
Explore CPU and Memory Usage
The moment to moment performance of an SQL database will be largely dependent on whether there are adequate hardware resources to cope with the volume of queries and processes that are running concurrently.
This is something you will have factored in when setting up the server, and yet it is also possible for unusual levels of usage to arise at certain times.
If your CPU is being pushed to the limits of its potential, or your memory is being monopolized, then something will have to give.
Often such scenarios may be something as simple as a rogue process which has gone haywire and needs to be terminated to restore order. Sometimes you may simply have reached a point at which your server hardware is no longer fit for the requirements you are placing upon it, in which case an upgrade will be necessary.
Investigate I/O Rates and Storage Capacity
The speed with which data moves within your server is another hardware-centric determining factor in performance. If I/O is unnaturally slow, falling below the specs of the drives you are using, then troubleshooting is needed.
Furthermore, the amount of storage you have available within your SQL server should be reviewed regularly. This is an especially important check, because the closer you come to capacity, the slower performance will be. And of course it is better to expand the storage before you ever reach this point. Scheduling maintenance and plotting in downtime, rather than having it occur unexpectedly, is strategically sensible.
Check for Software Updates
Last but by no means least, you need to be on the ball when it comes to looking out for software updates for your SQL server.
As well as providing performance improvements, updating to the latest software will ensure that your database is thoroughly protected from the various, ever-evolving security threats that exist today.
The longer you put off important maintenance checks like this, the tougher it will be to deal with problems further down the line, so act sooner rather than later to make your SQL server reliable and resilient.