By the way Miguel, I made a little Optimistic lock action utility
class to handle this (similar to how
ERXEOAccessUtilities.ChannelAction is constructed)... you might find
it useful....... example of usage nippet is shown after the class
listing below .......
<snip content = "snippet of static inner class from my EO utilities
class">
/**
* Deals with the nitty-gritty of a critical <strong>short-running</
strong>
* task where we depend on optimistic locking to guarantee that another
* process does not change optimistic locking attributes at the same
time. To
* understand why this is necessary, read this:
* {...@link http://terminalapp.net/dr-optimistic-locking/}.
*
* Wraps the actions in
* appropriate locks. WARNING: The OSC is locked for the period of the
* transaction. All EOF access on this OSC is blocked. Do not use
this for
* actions that take more than a few milliseconds on OSC's that are
being
* used by request threads!
*
* Code design inspired by {...@link ERXEOAccessUtilities.ChannelAction}
*
* @author kieran
*/
public static abstract class OptimisticLockAction {
/**
* This method is called in a new locked editing context that
has been
* created in the osc passed in. Perform your changes in this
editing
* context. Any errors will be thrown. Return any result you
want.
*
* @param osc
*/
protected abstract Object doPerform(EOEditingContext ec);
public Object perform() throws Exception {
return perform(null);
}
/**
* @param osc
* the root object store to be locked so that true
optimistic
* locking can be enforced.
* @return the result of your doPerform method implementation
* @throws Exception
*/
public Object perform(EOObjectStore osc) throws Exception {
osc.lock();
try {
ERXEC ec = (ERXEC) ERXEC.newEditingContext(osc);
ec.setCoalesceAutoLocks(false);
ec.setUseAutoLock(false);
ec.lock();
try {
// Don't use stale EO's to begin with
ec.setFetchTimestamp(System.currentTimeMillis());
return doPerform(ec);
} catch (Exception e) {
throw e;
} finally {
ec.unlock();
ec.dispose();
}
} catch (Exception e) {
throw e;
} finally {
osc.unlock();
}
}
}
</snip>
<snip content = "example usage">
// Create a new Optimistic Lock action
OptimisticLockAction action = new WKEOUtils.OptimisticLockAction() {
@Override
protected Object doPerform(EOEditingContext actionEditingContext)
{
CTCampaign localCampaign = (CTCampaign)
actionEditingContext.faultForGlobalID(gid, actionEditingContext);
try {
// Make the critical concurrent changes that depend on optimistic
locking failure
localCampaign.shipMessages();
actionEditingContext.saveChanges();
} catch (EOGeneralAdaptorException e) {
// Handle the optimistic lock failure ...
}
return null;
}
};
// Perform the optimistic lock action
try {
action.perform(parentObjectStore());
} catch (Exception e) {
// Unexpected exception
throw new NestableRuntimeException(e);
}
</snip>
On Dec 3, 2009, at 8:45 AM, Miguel Arroz wrote:
Hello
We use JMeter, not so much to test how much load can the server
get, but to test my beloved weird concurrency handling situations.
As almost any software in the world, it sucks specially at the UI
level (it's far from being integrated in OS X, not even copy/paste
works between it and the Mac world), and you have to allocate it a
lot of RAM or it will eventually blow up the heap, but it gets the
job done.
Yours
Miguel Arroz
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