Query Performance Optimization

To optimize query performance, be sure to do the following:

• Perform GROUP BY on the server whenever available. For instance, Crystal Reports gives you the option to group on the server as opposed to the client.
• Use DISTINCT to eliminate duplicate rows.
• Be specific when specifying tag names. For instance, when using wildcards, be as specific as possible.
• Limit the duration between start and end times.
• Get as precise a data type as possible to improve storage efficiency and allow reporting tools such as Crystal Reports to properly format the data in reports.
• Do not rely on TOP or ROWCOUNT to optimize performance, since they do not change the load on the archive or network. but instead they just limit what is returned to the caller.