Re: OSCPool/EO stack management/relaunch (was: Should ERXEC get sharedEC automagically?)
Re: OSCPool/EO stack management/relaunch (was: Should ERXEC get sharedEC automagically?)
- Subject: Re: OSCPool/EO stack management/relaunch (was: Should ERXEC get sharedEC automagically?)
- From: "ocs@ocs" <email@hidden>
- Date: Fri, 24 Aug 2018 04:03:45 +0200
Chuck,
I guess I have solved the mystery :) Looks like all what's needed is
- to set up freely the OSCPool with any number of coordinators
- at the init time, to use "isolation=serializable/locking=pessimistic" in my
models
- and switch off the SEC (by setting it to null in my ERXEC)
- when all the init work is done, I simply call
EODatabaseContext.forceConnectionWithModel(model,[URL:"jdbc:FrontBase://$dbhost/$dbname/user=$user/isolation=read_committed/locking=optimistic"],ec)
and that's that, it seems it works all right, for subsequently all
(session-based) ECs seem to work properly with the (OSC-based) SEC, and the
connexion indeed is read-committed/optimistic, as need be.
There's just one small thing I am not sure of: forceConnectionWithModel
re-connects “all compatible models in the model group” too. Alas the
documentation does not say what a “compatible” model is — what does that mean?
How does the EOF determine which models are compatible?
Thanks and all the best,
OC
> On 22 Aug 2018, at 2:06 PM, ocs@ocs <email@hidden> wrote:
>
> Chuck,
>
> hmmm... coudn't I somehow switch off temporarily the OSCPool, so that the
> initialisation code happens precisely as if there was no pool at all, and
> only then, when done, the pool starts behaving as normally? Actually I could
> benefit — if it is possible — from that, not only due to the SEC, but for
> other reasons as well (it would help if I could run the initialisation code
> against the DB in the “isolation=serializable/locking=pessimistic” mode,
> switching to “isolation=read_committed/locking=optimistic” for the normal
> processing).
>
> The init code just reads some objects from the db (including
> INFORMATION_SCHEMA, which is the reason for the DB mode), checks them,
> potentially updates them, and that's that — if at this moment the application
> quits and immediately runs again without the init code, it would work just as
> well. But for the objects in the shared EC, there's no EO which the init code
> would create/fetch and a later session-based code would use anyhow.
>
> I might switch off the SEC for the initialisation completely: I would run the
> init code using an EC with its SEC explicitly set to null, then somehow trash
> the init EO stack completely and start afresh with a new one (or ones with
> OSCPool) and normal session-based processing.
>
> Can this, i.e.,
>
> - to begin without OSCPool and connecting to DB in the
> “isolation=serializable/locking=pessimistic” mode;
> - do some stuff (without SEC), save changes;
> - completely trash the EO stack;
> - create a new one with OSCPool connecting to DB in the
> “isolation=read_committed/locking=optimistic” mode with SEC, and run happily
> ever after
>
> be done in some cleaner way than, well, restarting the application — which
> with some trickery exploiting Auto Recover in JavaMonitor might even prove
> possible, but would be super-ugly and I would rather do without?
>
> Thanks,
> OC
>
>> On 22 Aug 2018, at 5:11 AM, Chuck Hill <email@hidden
>> <mailto:email@hidden>> wrote:
>>
>> That is a good question. I’ve not used the combination. There must be
>> some code that uses the default instead of getting the SEC from the
>> EOEditingContext. There is a lot of code in Wonder (and some in WO) that
>> assumes the defaultWhatever is the only one that will ever exist. You would
>> have to step into the code to see where this is happening, or enable the
>> logging of stack traces of fetches. It should be a simple fix once you find
>> the spot.
>>
>> Chuck
>>
>> From: "ocs@ocs" <email@hidden <mailto:email@hidden>>
>> Date: Tuesday, August 21, 2018 at 1:02 PM
>> To: Chuck Hill <email@hidden <mailto:email@hidden>>
>> Cc: "email@hidden <mailto:email@hidden>"
>> <email@hidden <mailto:email@hidden>>
>> Subject: Re: Should ERXEC get sharedEC automagically?
>>
>> Indeed! If I switch off the OSCPool, it starts to work properly.
>>
>> Thanks just again!
>>
>> Nevertheless, I still must be missing something of grave importance, for
>> with OCSPool (I use ), I would presume the SEC for the pool being currently
>> used by the ERXEC would load the shared objects?
>>
>> It does not: the global one does automatically load the shared objects, but
>> the SEC-based one of ERXEC remains empty.
>>
>> Note: the code in question does not run in a session context; it is
>> performed at launch, before the first session is created. Might that be
>> important perhaps?
>>
>> All the best,
>> OC
>>
>>
>>
>> On 21 Aug 2018, at 9:42 PM, Chuck Hill <email@hidden
>> <mailto:email@hidden>> wrote:
>>
>> Are you using the ERXObjectStoreCoordinatorPool? It keeps one SEC per pool,
>> not one shared globally.
>> EOSharedEditingContext.defaultSharedEditingContext() is the global one.
>>
>> Chuck
>>
>> From: "ocs@ocs" <email@hidden <mailto:email@hidden>>
>> Date: Tuesday, August 21, 2018 at 12:23 PM
>> To: Chuck Hill <email@hidden <mailto:email@hidden>>
>> Cc: "email@hidden <mailto:email@hidden>"
>> <email@hidden <mailto:email@hidden>>
>> Subject: Re: Should ERXEC get sharedEC automagically?
>>
>> P.S. It seems ERX completely ignores the default shared EC, using its own
>> one. If I try e.g., this:
>>
>> ===
>> println "The default sharedEC is
>> ${EOSharedEditingContext.defaultSharedEditingContext()}"
>> 6.times {
>> def e=ERXEC.newEditingContext()
>> println "EC $e gets sec $e.sharedEditingContext"
>> }
>> println "The default sharedEC still is
>> ${EOSharedEditingContext.defaultSharedEditingContext()}"
>> ===
>>
>> it looks like this:
>>
>> ===
>> The default sharedEC is
>> com.webobjects.eocontrol.EOSharedEditingContext@26bbe604
>> 2005 [main] INFO er.extensions.eof.ERXObjectStoreCoordinatorPool -
>> initializing Pool...
>> 2008 [main] INFO er.extensions.eof.ERXObjectStoreCoordinatorPool -
>> initializing Pool finished
>> EC er.extensions.eof.ERXEC@40e32762 gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> EC er.extensions.eof.ERXEC@7d78f3d5 gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> EC er.extensions.eof.ERXEC@f5b6e78 gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> EC er.extensions.eof.ERXEC@71926a36 gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> EC er.extensions.eof.ERXEC@48976e6d gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> EC er.extensions.eof.ERXEC@7f6874f2 gets sec
>> com.webobjects.eocontrol.EOSharedEditingContext@5875de6a
>> The default sharedEC still is
>> com.webobjects.eocontrol.EOSharedEditingContext@26bbe604
>> ===
>>
>> Thanks and all the best,
>> OC
>>
>>
>>
>> On 21 Aug 2018, at 9:07 PM, ocs@ocs <email@hidden <mailto:email@hidden>> wrote:
>>
>> Chuck,
>>
>> sorry, I did not describe the problem clearly enough...
>>
>>
>>
>> On 21 Aug 2018, at 8:39 PM, Chuck Hill <email@hidden
>> <mailto:email@hidden>> wrote:
>> Once an EC has objects in it, its shared EC won’t get changed if a new
>> default is set. The notification is ignored.
>>
>> Quite, but that's not the problem.
>>
>> With EOEditingContext, it works like this:
>>
>> (i) ec created, has no sharedEC (ec.sharedEditingContext==null)
>> (ii) (due to something which creates a DBContext, I believe) the default
>> sharedEC is initialized; it loads the shared objects, and sends the
>> notification
>> (iii) ec observes the notification, and sets the default sharedEC as its own
>> sharedEC (for it is still empty)
>> (iv) now, ec fetches the objects — automatically giving shared ones from its
>> sharedEC, which does contain them
>>
>> With ERXEC (and ERXEC.useSharedEditingContext=true), there's an important
>> difference:
>>
>> (i) erxec created, immediately gets a sharedEC
>> (ec.sharedEditingContext!=null). This sharedEC differs from the default
>> shared EC
>> (ii) (due to something which creates a DBContext, I believe) the default
>> sharedEC is initialized; it loads the shared objects, and sends the
>> notification
>> (iii) erxec (although still empty) does nothing, it already has a sharedEC,
>> different from the default one
>> (iv) now, erxec fetches the objects — would automatically give shared ones
>> from its sharedEC, which, alas, contains nothing (the default one does).
>>
>> Thanks and all the best,
>> OC
>>
>>
>>
>>
>>
>> From: "ocs@ocs" <email@hidden <mailto:email@hidden>>
>> Date: Tuesday, August 21, 2018 at 11:21 AM
>> To: Chuck Hill <email@hidden <mailto:email@hidden>>
>> Cc: "email@hidden <mailto:email@hidden>"
>> <email@hidden <mailto:email@hidden>>
>> Subject: Re: Should ERXEC get sharedEC automagically?
>>
>> Chuck,
>>
>>
>>
>>
>> On 21 Aug 2018, at 7:50 PM, Chuck Hill <email@hidden
>> <mailto:email@hidden>> wrote:
>>
>> See er.extensions.ERXEC.useSharedEditingContext at
>> https://wiki.wocommunity.org/display/documentation/Explanation+of+the+default+properties+in+a+Wonder+project
>>
>> <https://wiki.wocommunity.org/display/documentation/Explanation+of+the+default+properties+in+a+Wonder+project>
>>
>> Thanks a lot!
>>
>> (Why on earth don't they mention this on the ERXEC documentation page? Oh,
>> never mind.)
>>
>>
>>
>>
>> Did that fix it?
>>
>> Well, sort of.
>>
>> It gets curiouser and curiouser — in other words, I must be doing something
>> far wrong.
>>
>> When I set the “ERXEC.useSharedEditingContext” property to true, then
>>
>> - the newly created ERXEC gets a shared editing context immediately upon
>> creation, not later upon receiving
>> DefaultSharedEditingContextWasInitializedNotification;
>> - and it is a different shared EC instance, not
>> EOSharedEditingContext.defaultSharedEditingContext()
>> - but it is EOSharedEditingContext.defaultSharedEditingContext() who reads
>> in automatically all the shared EOs
>> - and therefore, when fetching EOs through the ERXEC, I am still getting
>> non-shared ones in the ERXEC (for its own sharedEC is empty, and thus
>> EOSharedEditingContext.defaultSharedEditingContext is ignored).
>>
>> Can you make any sense of that?
>>
>> Thanks again a very big lot,
>> OC
>>
>>
>>
>>
>>
>>
>> On 2018-08-21, 9:43 AM, "Webobjects-dev on behalf of ocs@ocs"
>> <webobjects-dev-bounces+chill=email@hidden
>> <mailto:webobjects-dev-bounces+chill=email@hidden> on
>> behalf of email@hidden <mailto:email@hidden>> wrote:
>>
>> Hi there,
>>
>> the EOEditing context doc pretty unequivocally says
>>
>> ===
>> By default, an editing context that has no shared editing context listens
>> for DefaultSharedEditingContextWasInitializedNotifications. If a
>> notification is posted while the context has no registered objects, the
>> editing context sets its shared editing context to the newly initialized
>> default shared editing context.
>> ===
>>
>> Should it apply for an ERXEC, too? I sort of inferred it would, but by my
>> testing, it does not seem so: an ERXEC I make (through
>> ERXEC.newEditingContext()) seems to adamantly stay without
>> sharedEditingContext, although the notification is posted all right (I have
>> observed it myself to be sure), and if there's a good ole EOEditingContext,
>> it indeed duly sets its sharedEC at the time.
>>
>> Have I missed something of importance somewhere? The ERXEC documentation
>> does not say essentially anything of the sharedEC, far as I can say:
>>
>> http://wonder.sourceforge.net/javadoc/er/extensions/ERXEC.html
>> <http://wonder.sourceforge.net/javadoc/er/extensions/ERXEC.html>
>>
>> In principle, I could work around the problem by setting the sharedEC to
>> all my ERXECs programmatically -- that works all right --, but it would be a
>> lot of work, with a danger I overlook something somewhere and got bit in the
>> tender parts by that...
>>
>> Thanks,
>> OC
>>
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