Practices Properly Performing Index Maintenance in SQL Server

Ensuring the smooth, speedy operation of your SQL Server setup is important, and a major part of managing a database involves regularly maintaining the indexes.

There are several index maintenance strategies to prioritize, so let’s go through a few of the main methods so that database performance can be preserved.

Remedying Index Fragmentation

First and foremost, you need to cope with the unavoidable issue of index fragmentation, which is part and parcel of running a SQL Server instance and so needs to be on your watch list.


Fragmentation occurs as a result of the way that the tables within your database are interacted with by SQL queries. The more changes are made, the more fragmented the index will become. This is why periodic maintenance is necessary to prevent performance from suffering due to index fragmentation.

You can either defragment the index or rebuild it entirely, with the latter being suitable for cases where high levels of fragmentation are observed, and the former being appropriate if fragmentation levels are lower.

There are standard levels of fragmentation that can determine whether defragmentation or rebuilding is necessary. For fragmentation of between 5 and 30 percent, the simple reorganization will do the trick. For anything over this upper limit, rebuilding will be better.

Modern monitoring tools can keep tabs on index fragmentation levels and alert you to issues in this area. Just remember to schedule any defragmentation or rebuilding of indexes to times when the database is not under heavy loads, as otherwise, this might disrupt the experience for end-users of your web app or service.

When it comes to scheduling, this will depend on the scale of your SQL infrastructure. As a rule of thumb, tackling index fragmentation on a weekly basis is worthwhile, but remember to take your own circumstances and resources into account when planning this.

Eliminating Unnecessary Indexes

While in an ideal scenario each index will make your SQL database more efficient, it is also possible for indexes to become a burden if they are unnecessary or no longer used.

Again, with the right tools, you can seek out superfluous indexes and take them out of the equation. Likewise, if only a very small amount of data is being stored in a given table, then adding an index won’t be necessary and could compromise performance, so knowing when to skip over-indexing is just as important as correctly implementing them.

Embracing Automation

Last of all, do not forget that while you can manually perform index maintenance duties, it is far less hassle to hand this over to automated tools wherever possible.

As well as being able to monitor indexes, the latest solutions can fix fragmentation snafus and generally ensure that the right indexes are created and maintained over time.

You can also lessen index fragmentation by consolidating pages to avoid low densities. With experience and the right tools, index maintenance will become second nature as part of your broader database administrator duties and responsibilities.