Configuring the Volatile Attribute for Named Tables

Volatility is an indication to Spectrum Spatial that information from a data source can change at any time. The default value for TAB, and JDBC-based (Oracle, SQL Server and PostGIS) named tables is set to true, meaning that for each data access operation, such as a query or insert, Spectrum Spatial checks with the data source to find out if the table is volatile and if so, whether the data changed. If the data has changed, the cache is flushed and the table is reloaded before the data access operation can proceed. If the table did not change, the query or other operation is carried out on the data in the cache. See Supported Data Sources in the Resources and Data section of the Spectrum Spatial Guide for more information about for what triggers a change for each data source.

Volatility is disabled (set to false) for named tables that are uploaded from MapInfo Pro using Map Uploader. Volatility is enabled for any named tables created with Spectrum Spatial™ Manager. Older named tables in the repository are considered to be volatile but will not indicate that when viewed in the Spectrum Spatial™ Manager table details page.

Disabling volatility should be done only on tables that do not change. For example, when generating tiles from volatile TAB files, the operation will perform very slowly. If you are using PostGIS, you may also want to consider disabling volatility to avoid encountering connection errors in Spectrum Spatial™ Manager (for example, when viewing the sample rows on the table details page).

Volatility can be disabled on the table details page in Spectrum Spatial™ Manager. For more information on creating and modifying named tables in Spectrum Spatial™ Manager, see the Managing Spatial section of the Spectrum Spatial Guide.

You must restart the Spatial Module in Spectrum Spatial™ Manager when the named table is set as non-volatile.