MosherData

What Are Missing Index Suggestions?

Think of SQL Server’s query optimizer as a friendly detective. It monitors your queries and figures out where some extra indexing could make things zip along faster. It then hands you a list of these “missing” indexes, suggesting which columns to index and include. Pretty neat, right? Some folks even compare these suggestions to Clippy, the infamous Office assistant: well-meaning and sometimes helpful, but often just missing the mark.

Benefits of Missing Index Suggestions

  1. Performance: Adding these suggested indexes can make your queries fly.
  2. Indexing 101: They give you a clue on which columns need indexing.

Drawbacks of Missing Index Suggestions

  1. Index Overload: If you follow every suggestion blindly, you might end up with too many indexes. It’s like putting a turbocharger on a bicycle—too much of a good thing. Also, heavy and unnecessary.
  2. Tunnel Vision: These suggestions look at individual queries, not the big picture. They might miss out on how your app works overall.
  3. No VIP List: The suggestions aren’t prioritized. It’s like being handed a grocery list with no idea what’s for dinner.
  4. Column Order Confusion: The columns in the suggestions might not be in the best order for your needs.

Practical Application

Want to see these suggestions in action? It’s simple:

  1. Run a Query: Fire up a SELECT query with a WHERE clause.
  2. Check the Plan: Look at the execution plan for missing index suggestions.
  3. Weigh the Impact: Think about the suggested impact—it’s not always spot-on.
  4. Peek at the XML: For the overachievers out there, dive into the XML details of the execution plan.

Tips for Using Missing Index Suggestions

  1. Be Picky: Use the suggestions as starting points, not gospel. Tailor them to your data and queries.
  2. Prioritize Like a Pro: Since there’s no ranking, figure out which indexes will give you the biggest bang for your buck.
  3. Think Big Picture: Make sure your indexing strategy works for the whole application, not just individual queries.

Conclusion

SQL Server missing index suggestions are like your personal query performance advisors. Use them wisely, with a good dose of your own insight, and you’ll be speeding through queries in no time. Just remember, they can sometimes be like Clippy—well-meaning but not always on target. So, don’t get carried away and over-index!

Leave a comment