axis-java-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Amila Suriarachchi" <>
Subject Re: [axis2] Revisiting the Proposal for fixing out-of-memory error JIRA axis2-2968
Date Wed, 19 Sep 2007 08:19:09 GMT
On 9/19/07, Ann Robinson <> wrote:
> 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
> 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
>           (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

what is the parameter you have used for that? As I saw in your patch you
have changed the existing classes with out checking for a parameter.
As I saw this change is effect to the ?wsdl and wsdl2java tool and
wsdl11Axisservice builder at deployment time.
does all these cases work properly with imports and includes?
if these working features are preserved I am ok with this change.

                - - this could include serializing/deserializing the
> WSDL4J's WSDLDefinition
>                      object if the WSDLDefinition can be serialized
> Comments?
> - Thanks, Ann

Amila Suriarachchi,
WSO2 Inc.

View raw message