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From "nishant kumar (JIRA)" <axis-...@ws.apache.org>
Subject [jira] Commented: (AXIS-1771) Excessive Memory Use During Serialization/Deserialization
Date Wed, 19 Jan 2005 06:40:17 GMT
     [ http://issues.apache.org/jira/browse/AXIS-1771?page=comments#action_57757 ]
     
nishant kumar commented on AXIS-1771:
-------------------------------------

deserialization is taking so much memory because serialization has created too many multirefs.
even for ints. this happens because the int is wrapped as Integer and the code thinks that
it is not a primitive. so just added a method isPrimitiveWrapper which is used to prevent
creation of multirefs for primitive wrappers.

using this the size of the encoded string was reduced from 1170kb to 966kb and the memory
utilization during deserialization was also reduced by 2MB.

here is a solution for this.
just create

Index: src/org/apache/axis/encoding/SerializationContext.java
@@ -566,6 +566,22 @@
         return getTypeMapping().getTypeQName(cls);
     }

+
+       private boolean isPrimitiveWrapper(Object value)
+       {
+               if (value == null) return true;
+               Class javaType = value.getClass();
+               if (javaType == Integer.class) return true;
+               if (javaType == Long.class) return true;
+               if (javaType == Double.class) return true;
+               if (javaType == Float.class) return true;
+               if (javaType == Boolean.class) return true;
+               if (javaType == Short.class) return true;
+               if (javaType == Character.class) return true;
+               if (javaType == Byte.class) return true;
+               return false;
+       }
+
     /**
      * Indicates whether the object should be interpretted as a primitive
      * for the purposes of multi-ref processing.  A primitive value
@@ -800,7 +816,7 @@
             // Objects appear equal.

             if (doMultiRefs && isEncoded() &&
-                    (value != forceSer) && !isPrimitive(value)) {
+                    (value != forceSer) && !isPrimitive(value) && !isPrimitiveWrapper(value))
{
                 if (multiRefIndex == -1)
                     multiRefValues = new HashMap();


> Excessive Memory Use During Serialization/Deserialization
> ---------------------------------------------------------
>
>          Key: AXIS-1771
>          URL: http://issues.apache.org/jira/browse/AXIS-1771
>      Project: Axis
>         Type: Bug
>   Components: Basic Architecture
>     Versions: 1.2RC2
>  Environment: JDK 1.4.2, Mac OS X, Linux, Windows
>     Reporter: Peter Molettiere
>     Assignee: Venkat Reddy
>  Attachments: SerializationContext.java.diff, memory-use-test.tgz
>
> Axis uses pathological amounts of memory during the serialization/deserialization process.
> We see about a 30 to 1 ratio of memory used during (de)serialization to in-memory representation
of the objects being (de)serialized. So ser/deser in axis of a 2M graph of objects uses 288M
of memory! Further, the memory used seems to scale linearly with the size of the object graph
being serialized.
> The memory used does seem to be released once serialization is done, so this isn't a
leak.
> Using the attached example code, (based on the code used to demonstrate AXIS-1423) you
can see this behavior. The test automatically runs with a max heap size of 1024M, and runs
out of memory serializing a 28M object graph. 
> As provided, it generates the following output:
> Buildfile: build.xml
> build:
>     [javac] Compiling 1 source file to /Users/pietro/Work/Axis Memory Test/build/classes
> run:
>      [java] - Unable to find required classes (javax.activation.DataHandler and javax.mail.internet.MimeMultipart).
Attachment support is disabled. 
>      [java] Created tree with 5 levels and 3 children at each level
>      [java] Axis used 13 MBytes to serialize 230 KBytes, a ratio of 30.0
>      [java] GC freed 13 MBytes
>      [java] Created tree with 5 levels and 4 children at each level
>      [java] Axis used 71 MBytes to serialize 1 MBytes, a ratio of 31.0
>      [java] GC freed 71 MBytes
>      [java] Created tree with 5 levels and 5 children at each level
>      [java] Axis used 288 MBytes to serialize 2 MBytes, a ratio of 51.0
>      [java] GC freed 287 MBytes
>      [java] Created tree with 5 levels and 6 children at each level
>      [java] Axis used 671 MBytes to serialize 11 MBytes, a ratio of 29.0
>      [java] GC freed 675 MBytes
>      [java] Created tree with 5 levels and 7 children at each level
>      [java] Out of Memory serializing 28 MBytes tree.
>      [java] Java Result: 1
> BUILD SUCCESSFUL
> Total time: 2 minutes 51 seconds
> Note that the ratios are halved from the reported values, since it includes both serialization
and deserialization of the object graph. So axis uses 30.5M to serialize a 1M message, and
another 30.5M to deserialize it, resulting in the reported 71M reported above. Also, notice
that the ratio stays close to 30 to 1 regardless of object graph size. This is the linear
scaling I mention above.
> Note also, that if you tweak the code to generate very small object graphs, you see extremely
high ratios, but I would expect this due to simple one-time overhead to operate on very small
amounts of data. That's why I start with the graph size that I do.
>  

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