Run the Health Check Tool and select the Missing Index rule. This
rule looks for missing indexes.
To see information about Missing Indexes:
- Select the Missing Index Rule when you
Run the Health Check Tool.
You see the Missing Index results in the report.
![](images/missing_index_rule.png)
- Identify any tables with a high
TotalCost and high
IndexSeeks. Also look for values which are an
order of magnitude higher than the rest of the values; these tables are good
candidates to add indexes. In the example shown above, this would be the first
two rows.
- Identify any tables that have values in
EqualityUsage or
InequalityUsage. The indexes recommended by
those rows could also be good candidates. In the example above that would be
the fourth and fifth rows; with one index you also aggregate the cost of both
rows.
- Indexes need to be added using a Blueprint. Add the index to the
table and field identified and include the fields identified in the
IncludeColumns section.
Adding the recommended Include columns can help speed up the
query by covering the query. However, the more Include columns are added,
especially when they are key columns, the longer it can take to keep the
indexes up to date.
- The columns in the EqualityUsage indicate columns being used in
queries with equality predicates ("Select * from employee where id = 2") and
the InequalityUsage column displays columns being used in queries using
inequality predicates, for example, "Select * from employee where id > 2").