Query Store Isn’t A Forensics Engine

Grant Fritchey shows that Query Store has a limited capability of finding “ill-behaving” queries at a point in time:

Here’s a great question I received: We had a problem at 9:02 AM this morning, but we’re not sure what happened. Can Query Store tell us?

My first blush response is, no. Not really. Query Store keeps aggregate performance metrics about the queries on the database where Query Store is enabled. Aggregation means that we can’t tell you what happened with an individual call at 9:02 AM…

Well, not entirely true.

Query Store isn’t a total solution for “Why was the system slow at XX:XX?” types of questions.  This does not diminish its value as long as you do not try to treat it as your only monitoring solution.

Related Posts

Workload Analysis with Query Store

Erin Stellato shows how you can mine the Query Store tables to learn more about your workload: The query text and plan are stored in two separate tables, sys.query_store_query_text and sys.query_store_plan, respectively.  The text is stored as a nvarchar(max) data type, and the plan is stored as varbinary(max).  This means that the data can be […]

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Plan Forcing in Query Store

Erin Stellato continues a series on why you should be interested in Query Store: Before you go too crazy trying to stabilize performance with hundreds of forced plans, here are a couple things worth mentioning about plan forcing. 1. I think of plan forcing as a temporary solution. I do not view it as a […]

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