Hi, all, This is a re-send of the note with the correct [axis2] prefix in the subject line.
I have updated the proposed fix for the out-of-memory error that occurs on the server in some environments, and I would be interested in getting some feedback on the updated proposal. Some background: ---------------- This out-of-memory (OOM) error happens on the server in some environments where there is a large number of applications. At deployment time, when the applications are loaded, the AxisService objects are created. For those applications where the loading ends up invoking the WSDL11ToAxisServiceBuilder, the wsdl is read in and saved as a Parameter on the AxisService object. As the applications are loaded, an OOM happens before requests start flowing. In analyzing the java heap dumps, one of the biggest consumers of memory is with the wsdl4j WSDLDefinition objects. The heap dump indicates that the WSDLDefinition uses the xerces dom for underlying support, particularly for schemas. This makes the WSDLDefinition very heavy-weight. The heap dump also shows that the WSDLDefinition objects of concern are the ones being saved in the AxisService object's ParameterInclude list. Comments in the code (WSDL11ToAxisServiceBuilder) indicate that this is done so that, if some component needs to utilize the WSDLDefinition, the component can access it via a Parameter in the AxisService object. The initial proposed fix was to use a light-weight wrapper on the WSDL4J's WSDL definition object in order to release resources and reload WSDL if needed. Prototypes of this fix did resolve the OOM. This solution, however, had drawbacks with repect to custom WSDL locators and ?WSDL support. Updated Proposed Fix: --------------------- I have been working with the WSDL4J team on ways to reduce the memory footprint of the WSDL definition implementation. This means that a newer version of WSDL4J will need to be picked up by AXIS2 when the updated WSDL4J becomes available. In the meantime, for Axis2, I would like to propose using a wrapper on the WSDL4J's WSDLDefinition object for the following reasons: - to keep changes to the WSDL4J implementation from impacting users (especially those components that expect to access a WSDLDefinition from the parameter include list in the AxisService) - to allow certain environments to take advantage of changes in WSDL4J, (eg. new APIs, new steps, or catch exceptions) to reduce memory footprint - to have the option of doing an intermediate solution for certain environments while preserving current behavior of the Axis2 kernel for the rest of the environments The difference in this solution from the previously proposed solution is that - no resources will be released - no need to try to reload the original WSDL (so we don't have to worry about custom WSDL locators or ?WSDL support) This wrapper on the WSDLDefinition would do the following: - implement the wsdl definition interface and delegate the methods to the actual WSDL4J wsdl definition implementation that is being wrapped - provide tracing for debug situations - perform new steps to reduce memory footprint only when needed for certain environments - - this could be controlled via a configuration parameter so that the default behavior is the same as current behavior - - this could include serializing/deserializing the WSDL4J's WSDLDefinition object if the WSDLDefinition can be serialized Comments? - Thanks, Ann
