Symptoms
You may have some process which uses mail address in some query, for example as for notification and other standard workflow mails and observe that each of these queries takes at least 3 seconds to complete on SQL server side, leading to high CPU usage on SQL server for the related statement.
Diagnoses
If record SQL server trace you will be able to see queries similar to this one:
WITH XMLNAMESPACES('http://schemas.k2.com/identity/customProperties.xsd' AS n) SELECT [ID], [FQN], [Name], [Label], [Type], [Enabled], [Properties], [ExpireOn], [ExpireInterval], [Resolved], [ContainersExpireOn], [ContainersResolved], [MembersExpireOn], [MembersResolved], [Dynamic], [ProviderData] FROM [Identity].[Identity] AS CROSS APPLY I.Properties.nodes('/n:properties/n:item') AS Props(Prop)
WHERE ((Prop.value('@name','NVARCHAR(512)') = 'Email') AND (Prop.value('@value','NVARCHAR(512)') = 'workflow@domain.com')) AND [Enabled] = 1 AND [Type] IN (1)
And those queries may take something like 3 seconds to complete, and depending on your wokflows design and usage be executed with high frequency.
Resolution
This is known issue in K2 4.6.11 with available coldfix. You may observe K2 blackpearl host server slow performance when querying Identity Services when only using email address.
Please contact K2 support to obtain a coldfix for this issue referring the following coldfix internal ID: 609896.
