In Spotfire Data Virtualization, Work Load Management (WLM) memory rules are a critical feature designed to prevent queries against published objects from consuming excessive system resources and ensure overall stability. 

It's important to understand that when we define a WLM memory rule, such as setting a 35% threshold, this percentage is not calculated against the DV server's total Java Heap memory. Instead, it is calculated exclusively against the total managed memory allocated and configured for the Data Virtualization server instance.

The total managed memory of the DV server is determined by the "Percent of Memory to Manage (Current)" setting, which can be found and adjusted within DV Studio by navigating to Administration -> Configuration -> Server -> Memory -> Managed memory. This percentage represents the portion of the DV server's available memory that is configured to manage its operations, and it serves as the baseline for WLM rules.

Example:

With a 2 GB DV Java Heap and 70% Managed Memory, the baseline becomes 1.4 GB. Applying a 35% WLM rule to that baseline limits query consumption to 0.49 GB (approx. 500 MB).

This article describes how Work Load Management (WLM) memory rules in Spotfire Data Virtualization are calculated.