Running this script can generate Missing Column Statistics events. If those events are associated with statements that subsequently run longer, SQL Server is expressing a need for a user to...

The clause:

AND CAST(SUBSTRING(CONVERT(VARCHAR(10),h.run_date) , 5,2) +'-'

+ SUBSTRING(CONVERT(VARCHAR(10),h.run_date) , 7,2) +'-'

+ SUBSTRING(CONVERT(VARCHAR(10),h.run_date),1,4) AS SMALLDATETIME) = CONVERT(VARCHAR(10), GETDATE(), 121)

is destined to scan the entire sysjobhistory table.

For small sysjobhistory row counts, that...