ClearSCADA database indices are used to provide faster access to specific areas of the database. For example, the point index contains the point data, so you can use it to search through the point data without having to also search through the rest of the database.
Information about the various indices is shown in the Indices category:
The status information for the database indices is shown under these headings:
- Table—The table in the database to which the index applies.
- Obj Count—The total number of database items in the index.
- Access Count—The number of times the index has been used.
- Total Time—The total CPU time used to search the index.
- Avg Time—The average CPU time per search.
- Avg Hit Rate—The average number of 'hits' per search. A 'hit' is a match. For example, if there is a search for analog points, ClearSCADA uses an index of every database point. The hit rate will be a percentage based on the number of matching records in the entire index. So, if there were 100 database points and 48 of them are analog points, the Avg Hit Rate is 48%.
The Indices status information can be used to evaluate the performance of a ClearSCADA system. Typically, it is used by ClearSCADA engineers to determine whether the indices are appropriate.