Using Computed Fields to Chart Historical Trends
When you create a computed field, you typically configure it to calculate at a specific time in the future, storing the value in the history of each item containing the computed field. Command im analytics --recomputehistory -g calculates what the value of the computed field would have been at specific times and stores the value in the history of each item containing the computed field. This command is useful for discovering historical trends, such as how long a Defect item typically remained in state In Development in a current project compared to that of a previous project.
Key Considerations
• The command is required only if a new calculation is required over existing historical data.
• To use the command, you must either be an administrator or have type administrator permissions for all types that the specified field displays in.
• Depending on the options specified, the command may delete or modify item history.
• The command may take a long time to complete depending on:
◦ complexity of the underlying computed expression
◦ number of items containing the specified computed field
• The command renders item data as it existed at the specified time. For non-history data source (attachments, change packages containing entries that have moved, permissions, and administrative objects), the command approximates the historical data. To render non-history data sources as they were known at a specific time, you should define computed fields that use the static option under How to Run Computation, which captures historical values.
• Computed fields are calculated in the order that they appear in the item; however, if a computed field depends on the value of another computed field, it is calculated after the computed field containing the dependent value. Depending on the number of items in your database and the number of items containing computed fields that contain dependencies, it may take a long time to calculate the value of the computed fields.
• You can cancel this command at any time; however, it will not take effect until the specified interval calculation has completed. If you cancel this command, previous field values remain stored in the database. If the clear history option is selected and you cancel this command, item history is still cleared.
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