Extreme or incorrect values in the Mango data history have caused me a lot of problems (see the [url=http://mango.serotoninsoftware.com/forum/posts/list/1375.page Incorrect 0 point value...). We must have a way to locate and purge or modify selected data values in the PointValue history. I have deleted extreme values in the past via SQL, but these deletions are subject to errors (i.e. dangerous) and have often resulted in high-CPU usage problems that could only be rectified by restarting the Mango service.
While the "Discard extreme values" datapoint function is useful, it has limitations:
It only applies to new values; it does not remove extreme values from the point history In most cases the Discard feature is not enabled until extreme values have already been stored in the history The discard value will not discard invalid 0.00000 values; it will only discard extreme values If the Discard function is enabled, there is no way to detect the time, frequency, or value of the discarded data, which makes it difficult to troubleshoot and prevent extreme values from occurring in the future.[/list]It would be helpful if an optional alarm event were initiated each time an extreme value is discarded. The alarm would include the time stamp, the discarded value, and the discard threshold.
What we need most of all is a point history editor that provides a means to select points based on their value and timestamp meeting certain criteria, and then either purge or modify those values (e.g. multiply or add to the point).