From OpenSCADAWiki
These additional parameters:
- Archive size, days — determines the size of the archive over time. After exceeding the limit the old records will be deleted! Set to 0 to disable this limit and to rise some the performance.
- To form time as a string — store messages time in the readable form. Only for databases that support such by means of specific data types like "datetime" in MySQL.
This option is incompatible, that is, if you change it, you will lose your current archives. - Unique and non duple messages for time and category only — in the primary key there are used the fields MIN, TM, TMU and CATEG; otherwise the field MESS is included also to the primary key and is limited in 255 symbols.
