Load Testing CTools Applications

We are trying to load test our CTools dashboards and keep receiving "pt.webdetails.cda.exporter.ExporterException: IO Exception converting to utf-8" errors or "SEVERE: Mapped exception to response: 501", more detail below.

Has anyone had any experience with this type of issue in CTools? We only seem to receive these when load testing.

org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet PluginDispatchServlet threw exception
javax.ws.rs.WebApplicationException: pt.webdetails.cda.exporter.ExporterException: IO Exception converting to utf-8
at pt.webdetails.cda.CdaUtils$2.write(CdaUtils.java:292)
at com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider.writeTo(StreamingOutputProvider.java:71)
at com.sun.jersey.core.impl.provider.entity.StreamingOutputProvider.writeTo(StreamingOutputProvider.java:57)
at com.sun.jersey.spi.container.ContainerResponse.write(ContainerResponse.java:306)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1479)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1391)


SEVERE: Mapped exception to response: 501
javax.ws.rs.WebApplicationException: pt.webdetails.cda.dataaccess.QueryException: Error parsing parameters
at pt.webdetails.cda.CdaUtils.doQuery(CdaUtils.java:183)
at pt.webdetails.cda.CdaUtils.doQueryPost(CdaUtils.java:131)
at sun.reflect.GeneratedMethodAccessor165.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)




SEVERE: Mapped exception to response: 501