Lateral Cache Problems due to ObjectOutputStream Reset frequency

Hi JCS developers,
 
Recently, I've encountered a wierd behaviour regarding the synchronising of 
data across lateral caches. The problem occurs when a given LateralCache begins 
streaming the LateralElementDescriptor object to other laterals. It is 
discovered that the CacheElement.val property tends to reuse the value of a 
previously sent led (where the keys are the same). Following is an example of 
how caches will become unsynchornised:
 
LateralCache1 sends led (key="MyKey", value="MyValue1")
 
LateralCache2 received led (key="MyKey", value="MyValue1")
 
LateralCache1 sends led (key="MyKey", value="MyValue1,MyValue2")
 
LateralCache2 received led (key="MyKey", value="MyValue1")
 
 
I attempted to address this behaviour by adding in some debugging code:
 
In the try-catch block just before ObjectOutputStream writes the object 
 
oos.writeObject( led );
 
I added some debugging code at the send method 
 
//** Ben DEBUG Code (09/11/2005)
if ( log.isDebugEnabled() )
{
    log.debug( "BEN: Sending LateralElementDescriptor to other laterals " + 
"led = " + led + ", led.command = " + led.command + ", led.ce = " + led.ce );
}
 
Output is:
<Nov 9, 2005 3:52:07 PM ICT> <DEBUG> <LateralTCPSender> BEN: Sending 
LateralElementDescriptor to other laterals led = 
org.apache.jcs.auxiliary.lateral.LateralElementDescriptor@451523 
<mailto:org.apache.jcs.auxiliary.lateral.LateralElementDescriptor@451523> , 
led.command = 1, led.ce = [cacheName=DSMSDataCache, key=LoginValue-GROUPKEY, 
val=[74398d770ac5c563005ae9d6c8b00087, 7436cea60ac5c563005ae9d6a093a373], attr 
= [ IS_LATERAL = true, IS_SPOOL = true, IS_REMOTE = true, IS_ETERNAL = false, 
MaxLifeSeconds = -1, IdleTime = -1, CreateTime = 1131526327671, LastAccessTime 
= 1131526327671, getTimeToLiveSeconds() = -1, createTime = 1131526327671 ]]
 
 
To my surprise, before writing the object, the led value is correct, but at the 
receiving end at the LateralTCPListener, in the Thread's run method, the 
ObjectInputStream reads a stale value:
 
led = (LateralElementDescriptor) ois.readObject();
 
Output is:
<Nov 9, 2005 3:52:08 PM ICT> <DEBUG> <LateralTCPListener> receiving 
LateralElementDescriptor from anotherled = 
org.apache.jcs.auxiliary.lateral.LateralElementDescriptor@5d3aec 
<mailto:org.apache.jcs.auxiliary.lateral.LateralElementDescriptor@5d3aec> , 
led.command = 1, led.ce = [cacheName=DSMSDataCache, key=LoginValue-GROUPKEY, 
val=[7436cea60ac5c563005ae9d6a093a373], attr = [ IS_LATERAL = true, IS_SPOOL = 
true, IS_REMOTE = true, IS_ETERNAL = false, MaxLifeSeconds = -1, IdleTime = -1, 
CreateTime = 1131526327671, LastAccessTime = 1131526327671, 
getTimeToLiveSeconds() = 16, createTime = 1131526327671 ]]
 
 
I decided to change the constant value for RESET_FREQUENCY of the 
LateralTCPSender class to 1 (reset after every send), and the LateralCaches no 
longer have unsynchornised values.
 
Is there any impact to the performance of JCS by doing this? Could this be a 
minor fault with the JDK (I'm running on JDK131)?
 
 
 
Benjamin Foo
Technical Lead
Kasikornbank CMAS Corporate Project 
 
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