Thank you Rick,
We have already thought of building a summary table, but it is not possible. Since data may be accessed by various parameters.
Example:
- Get the average value with an interval of 30 minutes between the dates 2009-10-15 and 2009-12-23.
- Get the maximum values with an interval of 2 minutes between the dates 2010-01-02 and 2010-01-03
- Retrieve the minimum values with an interval of 2 days between the date 2008-01-01 and 2008-01-01
- ...
In short, the viewing parameters are configurable from a web interface and the user is free to groups and limit viewing based on what he wants.
Perhaps to get better performance, It would make more sense to use the TIMESTAMP and forget about the problem with the date superior to 2038. As you said, before this date the software will probably be replaced.