Project Name: XXXXXXXXX
Application
Type: Web
based Mobile application framework1. Problem:
The
session was not being handled efficiently in JMeter when we use the default
configuration of Cookie Manager.
Solution:
On
debugging the script I found an alternative method to handle session using the
Cookie Manager.
The
Cookie Policy was changed to “Default” and user defined cookies were manually
added.
Default Cookie Manager Setting:
Modified Cookie Manager Setting:
2. Problem:
The
CPU used to spike up to 25% for a single user. With the help of Jprofiler it
was seen that around 40% of the execution time was being consumed by
org.codehaus.jackson.map.ObjectMapper.writeValueAsString and org.codehaus.jackson.map.ObjectMapper.readValue.
Solution:
The
following alternate methods were used in the code in order to rectify the
issue:
GECAItem
getGECADataServices()
--> to get services
GECAItemAttribute
getGECAItemValue()
--> to get attribute value
GECAItemAttributeTrait
--> to get attribute trait value
getAttributeTraitValue()
GECAPresentationAttribute
--> to get presentation attribute value
getGECAPresentationAttributeValue()
GECAServiceParameter
-->to get parameter value
getServiceParameterValue()
3. Problem:
The following error was found in the application logs while executing the load test for 20 concurrent users.
SEVERE: Session event listener threw exception
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
Solution:
On analysis we found that a possible solution to avoid the ConcurrentModificationException is to implement Synchronization of threads in the code.
This was done by implementing the following in the code :
Map<String,Object> sessionMap = Collections.synchronizedMap(new HashMap<String,Object>());
Detailed description of above Solution :
If multiple threads access a hash map concurrently, and at least one of the threads modifies the map structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more mappings; merely changing the value associated with a key that an instance already contains is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the map. If no such object exists, the map should be "wrapped" using the Collections.synchronizedMap method. This is best done at creation time, to prevent accidental unsynchronized access to the map:
Map m = Collections.synchronizedMap(new HashMap(...));
4. Problem:
The application crashed on a concurrent load of 20 users after 20 min of the test run.
The application logs had the following error:
SEVERE:Servlet.service() for servlet appServlet threw exception
java.lang.StackOverflowError
at java.util.Hashtable.get(Hashtable.java:334)
at java.util.Properties.getProperty(Properties.java:932)
at java.util.Properties.getProperty(Properties.java:934)
Solution :
Memory allocation/memory leakage/garbage collection issue. to be handled by DB team.
The following error was found in the application logs while executing the load test for 20 concurrent users.
SEVERE: Session event listener threw exception
java.util.ConcurrentModificationException
at java.util.HashMap$HashIterator.nextEntry(HashMap.java:793)
Solution:
On analysis we found that a possible solution to avoid the ConcurrentModificationException is to implement Synchronization of threads in the code.
This was done by implementing the following in the code :
Map<String,Object> sessionMap = Collections.synchronizedMap(new HashMap<String,Object>());
Detailed description of above Solution :
If multiple threads access a hash map concurrently, and at least one of the threads modifies the map structurally, it must be synchronized externally. (A structural modification is any operation that adds or deletes one or more mappings; merely changing the value associated with a key that an instance already contains is not a structural modification.) This is typically accomplished by synchronizing on some object that naturally encapsulates the map. If no such object exists, the map should be "wrapped" using the Collections.synchronizedMap method. This is best done at creation time, to prevent accidental unsynchronized access to the map:
Map m = Collections.synchronizedMap(new HashMap(...));
4. Problem:
The application crashed on a concurrent load of 20 users after 20 min of the test run.
The application logs had the following error:
SEVERE:Servlet.service() for servlet appServlet threw exception
java.lang.StackOverflowError
at java.util.Hashtable.get(Hashtable.java:334)
at java.util.Properties.getProperty(Properties.java:932)
at java.util.Properties.getProperty(Properties.java:934)
Solution :
Memory allocation/memory leakage/garbage collection issue. to be handled by DB team.
