Indexes are crucial for SQL Server query performance. Everyone needs an Index. However, improper indexing strategies can degrade database performance, leading to slow queries and cause resource bottlenecks.
Effectively managing indexes involves not only identifying the missing ones that could improve performance, but also pinpointing unused indexes that unnecessarily consume system resources.
The following is shared in this post:
> Script 1: Check for Missing Indexes
> Script 2: Check for Un-used Indexes
> More Information
Script 1: Check for Missing Indexes
The script below returns missing index suggestions for the current database:
Use this script to identify and rank missing indexes based on SQL Server’s query analysis, prioritizing those with the highest impact. Refine suggestions based on your workload and performance goals. We should look at combining missing index suggestions with existing indexes to optimize performance.
For more information on this from Microsoft, have a look at this page: Tune nonclustered indexes with missing index suggestions
Script 2: Check for Unused Indexes
This script is for the indexes you don’t want. We’re able to check for un-used indexes indexes by analyzing index usage stats. Indexes with no recent seeks, scans, or lookups are considered candidates for removal.
To check for unused indexes in SQL Server, run the following:
Removing unused indexes can free up storage, reduce index maintenance overhead, and improve write performance. Before removing an index, ensure it is not indirectly supporting features such as indexed views or constraints.
More Information
To summarise, identifying missing indexes helps improve query performance, while removing unused indexes conserves resources and enhances system efficiency.
For more good information from myself, an experienced Microsoft SQL Database Admin, check out my post SQL Server Performance Tuning: Index Fragmentation Scripts, which is particularly useful to follow-on from this. The topic moves towards applying regular maintenance to the indexes you do want to keep around.
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