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, SAP HANA, 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 for what triggers a change for each data source.

Volatility is set to true for named tables that are uploaded from MapInfo Professional using Map Uploader. Volatility is true for any named tables created with Spatial Manager. Older named tables in the repository are considered to be volatile but will not indicate that when viewed in the Spatial Manager table details page.

Setting this flag to false should be done 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 setting this flag to false to avoid encountering connection errors in Spatial Manager (for example, when viewing the sample rows on the table details page).

To change the setting to false use the Volatility toggle on the table details page in Spatial Manager. See the Utilities section of the Spectrum Spatial Guide for more information on creating and modifying named tables in Spatial Manager.

You must restart the server when you change the volatile flag from false to true on any existing named table or when creating a new named table based on a database table that was previously set to false.