Configuring SQLTags Historian

SQLTag Historian providers are configured at SQLTags > Historian. A historian provider is created automatically for each database connection, and will be removed if the connection is removed. Although enabled by default, the providers won't interact with the database unless data is logged to them.

General Settings

Enabled

Whether the provider will be turned on and accept tag history data. If disabled, any data that is logged to the provider will error out and be quarantined by the store and forward engine, if possible.

Data Partitioning

SQLTags Historian can partition the data based on time in order to improve query performance. Partitions will only be queried if the query time range includes their data, thereby avoiding partitions that aren't applicable and reducing database processing. On the other hand, the system must execute a query per partition. It is therefore best to avoid both very large partitions, and partitions that are too small and fragment the data too much. When choosing a partition size, it is also useful to examine the most common time span of queries.

Partition Length and Units

The size of each partition. The default is one month. Many systems whose primary goal is to show only recent data might use smaller values, such as a week, or even a day.

Data Pruning

The data prune feature will delete partitions with data older than a specific age. It is not enabled by default.

Enable

Monitor the partitions and drop those whose data is older than the specified age.

Prune Age and Units

The maximum age of data. As mentioned, the data is deleted by the partition, and could therefore surpass this threshold by quite a bit before all of the data in the partition is old enough to be dropped.