If an SQL server deployment is performing poorly, it can have serious ramifications for entire organizations.
As such, taking the time to get to know the most common issues so that you can troubleshoot them effectively is a sensible step.
Here is a look at the main conundrums any database administrator will face in the course of their duties, and the options they have for overcoming them.
SQL Coding Bad Habits That Lead to Inefficient Queries
Suboptimal query writing is often the cause of some of the more commonplace yet difficult-to-detect complications that can arise within an SQL server ecosystem.
The only answer to this is to address the bad habits you may have developed and aim to avoid them in the future, whether that might mean dealing with NOLOCK over-use, avoiding an entire index scan when looking for specific data, or generally going back to basics and recognizing that excessively complex query structures and execution plans can be worse than more straightforward equivalents.
Improper TempDB Configuration That Increases the Likelihood of Downtime
TempDB is a crucial resource within every SQL server instance, allowing transitory data to be stored for as long as it is needed by a process.
If TempDB fills up, the whole database will come grinding to a halt, so staying on top of this particular piece of maintenance is definitely advisable.
You can avoid this by ensuring that there is adequate storage assigned to TempDB in the first place and that temporary data is being culled correctly after the process using it has been completed. Likewise, you can avoid the hardware itself becoming a bottleneck by assigning TempDB to solid-state storage rather than spinning disks, depending on your needs and budget of course.
Index Fragmentation is Overlooked and Performance Suffers
Indexes need to be well maintained to prevent the inevitable fragmentation that occurs from compromising the speed with which queries are executed and data retrieved from your SQL server.
Defragmenting and rebuilding indexes in an efficient way that does not interfere with the everyday operations of the database is all about timing. Set a maintenance schedule that meshes well with the peaks and troughs of server usage, and also keep an eye on how quickly fragmentation levels rise so that you can gauge exactly how frequently it will be necessary to step in and fix this.
Like many aspects of SQL server troubleshooting, it is something of a balancing act that you will be better able to cope with time and with experience.
Overworked Hardware is Falling Short of Your Needs
While suboptimal queries and poorly maintained indexes might cause mischief and stifle server performance, it is also necessary to consider that your SQL database may simply have outgrown the capabilities of the hardware powering it.
It is therefore important to be aware of this likelihood arising at some point in the future and use a persistent approach to monitoring to plan ahead for upgrades that will avoid major bottlenecks arising unexpectedly.
Keeping tabs on storage usage is obviously sensible, but you should also be aware of how many of your other server resources are being deployed from day to day. If your CPU is being thrashed close to its limits, or your memory allocation is almost saturated, then you need to be prepared to either update your existing setup or migrate to a more capable solution entirely.
Most of all, you have to accept that effectively troubleshooting an SQL server is a never-ending process, rather than one which has a definite endpoint.