Index Analysis 
Indexes are essential for fast and efficient access to the data of the database instance. At regular intervals, check whether the indexes in the database system or SAP system are missing or bad. This is particularly important after major actions, such as an upgrade.
There are two possible types of inconsistency:
Indexes exist in the database instance, but are not defined in the ABAP Dictionary
Indexes are defined in the ABAP Dictionary, but are not included in the database instance, or are bad
Procedure
You have the following options for the index analysis:
DBA Cockpit: Indexes, Tables/Views/Synonyms, Missing Tables and Indexes
Database/liveCache Assistant: Indexes, Tables/Views/Synonyms
Bad indexes are displayed in the Properties (DBA Cockpit/Database/liveCache Assistant).
Database Alert Monitor or liveCache Alert Monitor: Bad Indexes
Database Alert Monitor: SAP Consistency
Result
Always recreate a missing index immediately, since it is very important for database system functionality. Indexes are used for special table scans and are important for performance.
You can use the database utility to recreate missing indexes (defined in the ABAP Dictionary, missing in the database instance).
More Information
Database-ABAP Dictionary Consistency
Executing Performance Analysis in CCMS
Database Manager GUI, Activating, Deactivating, or Deleting Indexes, Restoring Indexes After Database Restore
Database Studio, Index: Create/Edit/Delete, Restore Index