Metrics install automatically if you have Redgate Monitor installed.
If you are using Redgate’s SQL Server monitoring tool, Redgate Monitor, you can instantly install and run this metric on your servers.
This metric returns the number of check constraints that have their is_not_trusted flag set to 1 in the sys.check_constraints table. Untrusted constraints force SQL Server to construct less efficient query plans, because it doesn’t know enough about the kind of data contained in the table. This can point to a data integrity issue which should be investigated.
If the metric and alert tells you that untrusted constraints exist, find out which ones they are by running:
[sql]SELECT * FROM sys.check_constraints WHERE is_not_trusted = 1 AND is_not_for_replication = 0[/sql]
For details of how to fix them, see Brent Ozar’s article: Blitz Result: Foreign Keys or Check Constraints Not Trusted.
Metric definition
Name
Untrusted check constraints
Description
The number of check constraints that have their is_not_trusted flag set to 1 in the sys.check_constraints table.
If untrusted check constraints exist, find out which ones they are by running:
SELECT * FROM sys.check_constraints WHERE is_not_trusted = 1 AND is_not_for_replication = 0
The T-SQL query that will collect data
Instances to collect from
Select all
Databases to collect from
0
Collection frequency
86400
Use collected or calculated values
Leave the Use a calculated rate of change between collections check box unchecked
Metric collection
Enabled
Alert definition
Alert name
Untrusted check constraints
Description
This alert is raised when SQL Monitor detects check constraints that have their is_not_trusted flag set to 1 in the sys.check_constraints table.
To find out where untrusted check constraints exist, run:
SELECT * FROM sys.check_constraints WHERE is_not_trusted = 1 AND is_not_for_replication = 0
Raise an alert when the metric value goes
Above the defined threshholds
Default threshold values
High: | 0 |
Medium: | Disabled |
Low: | Disabled |
Raise an alert when the threshold is passed for
1 collection
Alert is
Enabled