Query Store Plan Forcing: You Can’t Always Get What You Want

Kendra Little shows an example where trying to force a Query Store plan results in an oddity:

This is not considered a “failure”

When I check the Query Store DMVs, force_failure_count is 0. The last_force_failure_reason_desc is NONE.

Query Store didn’t fail to apply the narrow plan. Instead, it’s just deciding not to give it to me, now that I’ve forced that plan.

Seems kinda like an adolescent, doesn’t it?

The answer remains a bit of a mystery, but read on to see how Kendra troubleshoots this.

Related Posts

Monitoring Query Store Space usage

Erin Stellato has a process which alerts her when query store space utilization reaches a defined threshold: For those of you not familiar with the Query Store settings, please check out my post which lists each one, the defaults, and what I would recommend for values and why.  When discussing MAX_STORAGE_SIZE_MB, I mention monitoring via sys.database_query_store_options or […]

Read More

Trying To Force A Plan For A Different Query With Query Store

Erin Stellato shows us that you cannot use a plan generated for one query as a forced plan for a different query in Query Store: This is question I’ve gotten a few times in class…Can you force a plan for a different query with Query Store? tl;dr No. Assume you have two similar queries, but […]

Read More

Categories

November 2017
MTWTFSS
« Oct Dec »
 12345
6789101112
13141516171819
20212223242526
27282930