Re: ERXObjectStoreCoordinator can be locked twice?!?

Subject: Re: ERXObjectStoreCoordinator can be locked twice?!?
From: Chuck Hill <email@hidden>
Date: Tue, 27 Jan 2015 23:32:47 +0000
Thread-topic: ERXObjectStoreCoordinator can be locked twice?!?

On 2015-01-27, 3:28 PM, "Ramsey Gurley" wrote:

On Jan 27, 2015, at 4:19 PM, Chuck Hill <email@hidden> wrote:

Are you using this?

/**

* This class implements EOF stack pooling including EOF stack synchronizing.

* It provides a special ERXEC.Factory in order to work without any changes in existing

* applications. The number of EOObjectStoreCoordinators can be set with the

* system Property <code>er.extensions.ERXObjectStoreCoordinatorPool.maxCoordinators</code>.

* Each Session will become one EOObjectStoreCoordinator and the method

* <code>newEditingContext</code> will always return an <code>EOEditingContext</code>

* with the same <code>EOObjectStoreCoordinator</code> for the same <code>WOSession</code>.

* This first release uses round-robin pooling, future versions might use better algorithms

* to decide which <code>EOObjectStoreCoordinator</code> will be used for the next new

* <code>WOSession</code>.<br>The code is tested in a heavy multithreaded application

* and afawk no deadlock occures, neither in EOF nor directly in Java.

*

* @author David Teran, Frank Caputo @ cluster9

*/

publicclass ERXObjectStoreCoordinatorPool {

I think so. From a different thread:

another weird case: this application is run single-instance (but ERXObjectStoreCoordinatorPool.maxCoordinators=3, WOAllowsConcurrentRequestHandling=true).

OK, so that handily explains the OSC lock logging below – they are different OSC instances. Single instance and three stacks seems odd, like someone maybe misunderstood what this was doing?

On 2015-01-27, 3:04 PM, "OC" wrote:

Hello there,

since I wrote an awk script to check whether my OSCs get unlocked properly, I've bumped into one very strange thing in the locks.

First, my code is pretty straightforward (assuming we should lock OSC at all, which is debatable -- based on http://terminalapp.net/dr-optimistic-locking/; Chuck says well all right, though it should be sufficient to catch some notifications instead):

===

        EOEditingContext ec=auction.editingContext()

        EOObjectStore osc=ec.rootObjectStore()

        osc.lock()

        try {

            logln "$osc LOCKED FOR CU $sess.currentUser.login"

            EOEditingContext tempec=ERXEC.newEditingContext()

            ... creating localInstanceIn as needed, updating them as appropriate …

Wat?

http://i0.kym-cdn.com/photos/images/newsfeed/000/173/580/Wat.jpg?1315930588

I don’t understand why this would be necessary, and I’m afraid to ask ;-) Anyway,

You’ve met Miguel, right? :-)

http://terminalapp.net/dr-optimistic-locking/

//You should be doing this if you want to ensure a peer ec in the same osc

EOEditingContext tempec = ERXEC.newEditingContext(osc);

Yes with multiple stacks NOT doing that could lead to unexpected results.

            tempec.saveChanges()

            println "... saved successfully!"

       } catch (exc) {

            ... reporting and logging error -- does not happen ...

       } finally {

            osc.unlock()

            println "$osc UNLOCKED FOR CU $sess.currentUser.login"

       }

===

and in one place in my logs, there is

===

26.1 14:06:03: er.extensions.eof.ERXObjectStoreCoordinator@5d5e3b92[name=unnamed] LOCKED FOR CU CEZProdej

... saved successfully!

26.1 14:06:03: er.extensions.eof.ERXObjectStoreCoordinator@5d5e3b92[name=unnamed] LOCKED FOR CU EPETas

... saved successfully!

er.extensions.eof.ERXObjectStoreCoordinator@5d5e3b92[name=unnamed] UNLOCKED FOR CU CEZProdej

er.extensions.eof.ERXObjectStoreCoordinator@5d5e3b92[name=unnamed] UNLOCKED FOR CU EPETas

===

What the darn?!? This should not be possible, or am I completely missing the point of osc.lock()?!? :-O

In the vicinity, all the other logs looks all right, no exception not other error reported.

As usual, I'll be pretty grateful for any insight,

OC

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Follow-Ups:
- Re: ERXObjectStoreCoordinator can be locked twice?!?
  - From: OC <email@hidden>
- Re: ERXObjectStoreCoordinator can be locked twice?!?
  - From: Ramsey Gurley <email@hidden>

References:
	>ERXObjectStoreCoordinator can be locked twice?!? (From: OC <email@hidden>)
	>Re: ERXObjectStoreCoordinator can be locked twice?!? (From: Chuck Hill <email@hidden>)
	>Re: ERXObjectStoreCoordinator can be locked twice?!? (From: Ramsey Gurley <email@hidden>)

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