Which are the database tables to be queried for performance data?
Here are the details that might help you extract reports by connecting to the database:
The data in the raw table, i.e., STATSDATA table, is maintained for 7 days by default and can be incremented to a max of 15 days. In _HOURLY table, the data is maintained for 30 days by default, and can be incremented to 90 days max. Similarly, the data in the _DAILY table is maintained for 365 days, and can be pushed upto 3650 days max. This maintenance can be configured from Settings → General Settings → Database Maintenance option.
The data used for displaying performance graphs will be controlled by both the Database Maintenance Settings and the Graph Display Settings. Make sure the values provided in Graph Display Settings is lesser than the corresponding value in Database Maintenance settings to ensure graphs are displayed properly.
For example, if the Detailed raw data retention time is set to 7 days and the Detailed statistics retention limit in the Graph Display Settings is set to 8 days, there won't be enough data from the Detailed table for OpManager to display graphs and so the data from the Hourly table will be used instead.