Specifying class indexes from the Class Manager
The BMC Atrium CMDB Class Manager helps you index your classes. Indexing classes can reduce database query time. Index attributes that you expect users to query frequently, are used by discovery applications to identify Configuration Items (CIs), and are used in reconciliation identification rules. For more information about identification rules, see Creating an identification ruleset for reconciliation.
Creating or modifying classes process
Specifying or modifying indexes in a class that already holds a large number of instances can take a significant amount of time and disk space. Therefore, avoid creating indexes during normal production hours. For more information about BMC Remedy AR System indexes, see Defining indexes.
To specify a custom class index
The following steps are for adding custom indexes only. If you have to add missing system indexes, see Troubleshooting performance issues caused by missing CMDB indexes.
- In the Class Manager, open a class for editing.
- In the General tab of the CI Class or Relationship Class dialog box, expand the Indexes section.
- Click New.
- In the Name field of the Index dialog box, enter a name for the new index.
- Add at least one field to the index:
- Select one or more fields in the Fields on Form table. If you want to select multiple fields for a composite index, press the Ctrl key as you select fields.
- Click Add.
- (optional) Specify indexing characteristics for the fields in the index:
- In the Index dialog box, click OK.
- Repeat step 3 through step 7 for other indexes you want to create for this class.
- Perform one of the following actions:
You want to provide additional information for the class
Continue with the process described in Process overview for creating or modifying classes.
You are finished working with this class
Indexes and class attributes
If you create an index for a
Character attribute, you can save query time by setting the QBE Match characteristic of that field to Leading or Equal instead of Anywhere.
Use the Indexes section on the General tab of the CI Class and Relationship Class dialog boxes to specify the indexes for a class. You can specify indexes on non-inherited attributes only. If an attribute is inherited form a superclass, you must specify the index for that attribute on the superclass. Display-only attributes cannot be indexed, because no values are stored for them.
To combine multiple attributes into a composite index, specify as many as 16 attributes per composite index. The sum of all attribute lengths in a single index must be fewer than or equal to 255 bytes, so
Diary attributes and
Character attributes larger than 255 bytes cannot be indexed.
More time is required to modify a class (for example, adding new attributes) when indexes have been specified for it. The greater the number of indexes specified for the class, the more time and disk space are required. Specifying and modifying instances also takes longer for classes with many indexes.