Chuck,
well, so far, I have found two problems with SEC. One of them is boringly
self-evident, but a hell to find&fix: very simply, my legacy code did contain
something like
Foo something() {
...
EOUtilities.objectWithPrimaryKeyValue(this.editingContext(),'NonSharedFooEntity',pk)
}
Which, of course, if this was shared, loads the object into SEC, and hilarity
ensues. I wonder how many similar traps there are in my legacy code...
The other case though is weird. You might recall that my code
- first does some special initialisations without a SEC (all the ECs I use has
their SEC immediately upon creation set to nulls)
- when done, I change the connection dictionary, re-connect using
EODatabaseContext.forceConnectionWithModel, and run on normally with SECs.
The problem is that during the special init code I happen to need a DBC; and it
seems that the code
def
ctxt=ERXEOAccessUtilities.databaseContextForEntityNamed(ec.rootObjectStore(),someEntity.name)
always initialises the default SEC and loads the shared EOs into it —
regardless the fact that the ec does not have a SEC at all.
Subsequently, I change (in the EC without a SEC) some shared EOs. The
documentation says that SEC would observe such changes and would refetch those
shared EOs into a SEC; well, it does, but not when they happen, nor when the EC
is saved, nor when it is unlocked — far as I was able to find, it happens only
when the EO in the SEC is touched (i.e., its attribute is read).
If this does not happen, i.e., if the previously changed shared EO is not
touched in the SEC, a first fetch into a normal EC (with SEC) whose fetch spec
happens to include a changed shared EO crashes. In other words, it goes like
this:
(a) init-time, I am consistently using ECs with null SEC;
(b) with one of those, I call databaseContextForEntityNamed, which initializes
and populates the default SEC;
(c) later, in the EC with null SEC, I fetch and change a couple of shared EOs
(they do not get re-loaded in SEC!)
(d) later, normal-run-time, I fetch objects into an EC with SEC; the fetch spec
happens to fit some shared EOs...
... and it results in a EOEditingContext: initializeObject: attempt to
initialize object ... that exists in a shared context via a non-shared context.
[1]
I have found that the culprit object is one of those changed in the step (c),
and I have found that touching the shared EO in the SEC before the fetch helps:
the shared EO gets re-loaded, and the fetch works as presumed (returning the
shared EO in the SEC). Now, I do this:
- whenever the SharedEditingContextInitializedObjectsNotification comes, I
record the SEC;
- after the shared EOs are changed (in an EC with null SEC) and saved, I go
through all the SECs recorded; for each of them I get all its
registeredObjects, and for each of them call eo.storedValueForKey(anyKey). If
the object has been changed, this re-loads it in SEC, and subsequent fetching
works properly.
This seems to me extremely weird. Can you understand what the heck happens
there and why?
Thanks and all the best,
OC
[1] it looks like this: with fetch code like
println "FETCH $ec SEC:$ec.sharedEditingContext
RELS:${EOModelGroup.defaultGroup.entityNamed(fs.entityName).relationships}"
found=ec.objectsWithFetchSpecification(fs)
println "FETCH $ec SEC:$ec.sharedEditingContext got $found"
it quite consistently crashes like this:
FETCH er.extensions.eof.ERXEC@11a11fbb
SEC:com.webobjects.eocontrol.EOSharedEditingContext@79c3f01f RELS:[]
9301 [WorkerThread5] INFO er.transaction.adaptor.Exceptions - Database
Exception occured ...
... ...
Caused by: java.lang.IllegalArgumentException: EOEditingContext:
initializeObject: attempt to initialize object with global ID
_EOIntegralKeyGlobalID[DBDFList (java.lang.Integer)100] that exists in a shared
context via a non-shared context. The object model may have a relationship from
a shared entity to a non-shared entity. Disable or remove the relationship from
the model.
at
com.webobjects.eocontrol.EOEditingContext.initializeObject(EOEditingContext.java:3760)
at er.extensions.eof.ERXEC.initializeObject(ERXEC.java:1237)
at
com.webobjects.eoaccess.EODatabaseChannel$_EODatabaseChannelFetchResult.initializeObjects(EODatabaseChannel.java:496)
at
com.webobjects.eoaccess.EODatabaseContext._objectsWithFetchSpecificationEditingContext(EODatabaseContext.java:3090)
at
com.webobjects.eoaccess.EODatabaseContext.objectsWithFetchSpecification(EODatabaseContext.java:3195)
at
com.webobjects.eocontrol.EOObjectStoreCoordinator.objectsWithFetchSpecification(EOObjectStoreCoordinator.java:488)
at
com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4069)
at
er.extensions.eof.ERXEC.objectsWithFetchSpecification(ERXEC.java:1307)
at
com.webobjects.eocontrol.EOEditingContext.objectsWithFetchSpecification(EOEditingContext.java:4444)
at
com.webobjects.eocontrol.EOEditingContext$objectsWithFetchSpecification$0.call(Unknown
Source)
if, though, I programmatically find the object which is to be fetched in the
SEC and touch it like this:
println "FETCH $ec SEC:$ec.sharedEditingContext
RELS:${EOModelGroup.defaultGroup.entityNamed(fs.entityName).relationships}"
ec.sharedEditingContext.registeredObjects.findAll {
it.entityName==fs.entityName && fs.qualifier.evaluateWithObject(it) }.each {
it.storedValueForKey('title') // sufficient to touch the thing to reload it
in SEC; without it is never reloaded and causes the crash
}
found=ec.objectsWithFetchSpecification(fs)
it never crashes; and, as soon as storedValueForKey is called, the object is
re-loaded in the SEC. It is sufficient to out-comment the storedValueForKey to
get the attempt to initialize object ... that exists in a shared context crash
back. Far as the storedValueForKey is there, it does not crash.
> On 26. 9. 2018, at 7:12 PM, Chuck Hill <ch...@gevityinc.com> wrote:
>
> Hi OC,
>
> No, no magic like that. At least not that I know of. Subclassing
> EOEditingContext, EOSharedEditingContext, maybe EODatabaseContext is probably
> your best bet to pursue this.
>
> Chuck
>
> From: "ocs@ocs" <o...@ocs.cz <mailto:o...@ocs.cz>>
> Date: Wednesday, September 26, 2018 at 8:40 AM
> To: Chuck Hill <ch...@gevityinc.com <mailto:ch...@gevityinc.com>>
> Cc: WebObjects-Dev Mailing List <webobjects-dev@lists.apple.com
> <mailto:webobjects-dev@lists.apple.com>>
> Subject: Re: Flattened one-side M:N fails wildly with SharedEC
>
> Chuck,
>
>
> On 19 Sep 2018, at 9:57 PM, Chuck Hill <ch...@gevityinc.com
> <mailto:ch...@gevityinc.com>> wrote:
> Uh oh, the dreaded Schrödinger EOF behaviour! Have you figured anything out?
>
> Alas, nope. The darned “The shared context recently initialized the object
> ...” thing occurs intermittently, and whenever I add extra logs to find the
> culprit, it disappears. To occur again the next day or the next week.
>
> Is there some trick to set up something somewhere so that
>
> (a) until the SEC tries to load a non-shared object, all runs normally, there
> are no extra logs nor big performance delays,
> (b) but, as soon as that happens, I get a very detailed log which would not
> only say which object is the culprit, but also the reason why has it been
> loaded into SEC, through which relationship, etc.?
>
> Thanks and all the best,
> OC
>
>
>
> From: "ocs@ocs" <o...@ocs.cz <mailto:o...@ocs.cz>>
> Date: Wednesday, August 29, 2018 at 12:38 PM
> To: Chuck Hill <ch...@gevityinc.com <mailto:ch...@gevityinc.com>>
> Cc: WebObjects-Dev Mailing List <webobjects-dev@lists.apple.com
> <mailto:webobjects-dev@lists.apple.com>>
> Subject: Re: Flattened one-side M:N fails wildly with SharedEC
>
> Darn...
>
>
>
> might have been caused by something else, which is just loosely related to
> the change — a log in the code for all I know; the Schrödinger EOF behaviour
> did bit me once or twice already
>
> ... I should have not written this part!
>
> I have seen the blasted “The shared context recently initialized the object
> ...” thing again.
>
> Added log to pursue it. It did not happen.
>
> Removed the log. It still did not happen.
>
> Curiouser and curiouser...
>
> Thanks and all the best,
> OC
>
>
>
> On 29 Aug 2018, at 7:49 PM, ocs@ocs <o...@ocs.cz <mailto:o...@ocs.cz>> wrote:
>
> Chuck,
>
>
>
> On 29 Aug 2018, at 7:14 PM, Chuck Hill <ch...@gevityinc.com
> <mailto:ch...@gevityinc.com>> wrote:
> I am not sure that I am following this correctly. The rule is that no Shared
> EO should have a relationship to anything that is not also a Shared EO.
>
> The opposite direction (from normal EC to SEC) should be all right though,
> should it not?
>
>
>
> That includes the tables not materialized into an EO.
>
> I do not follow here.
>
> My shared entity S had no relationship to non-shared ones at all. Not even an
> empty one; none altogether.
>
> My non-shared entity A has a to-many relationship “aaa” to a non-shared B; B
> has a to-one relationship “bbb” to shared S (no inverse here). B is the M:N
> table, i.e., it contains just the A's and S's PKs.
>
> When non-shared A contained a flattened relationship “ddd” defined as
> “aaa.bbb”, EOF kept trying to load A into SEC (which naturally failed).
>
> I've removed the flattened “ddd” from the model (no other change there), and
> implemented its behaviour manually (in A just getting “aaa” programmatically,
> and then for all its objects collecting their “bbb”'s), and the problem
> disappeared; A has been no more loaded to SEC.
>
> Of course, it might have been caused by something else, which is just loosely
> related to the change — a log in the code for all I know; the Schrödinger EOF
> behaviour did bit me once or twice already :) it does seem very weird to me
> that the flattened thing should be the culprit; that's why I am asking
> whether such kind of behaviour is to be expected, or whether I should try to
> hunt for the culprit elsewhere.
>
> Thanks and all the best,
> OC
>
>
>
>
> From: Webobjects-dev
> <webobjects-dev-bounces+chill=gevityinc....@lists.apple.com
> <mailto:webobjects-dev-bounces+chill=gevityinc....@lists.apple.com>> on
> behalf of "ocs@ocs" <o...@ocs.cz <mailto:o...@ocs.cz>>
> Date: Wednesday, August 29, 2018 at 8:28 AM
> To: WebObjects-Dev Mailing List <webobjects-dev@lists.apple.com
> <mailto:webobjects-dev@lists.apple.com>>
> Subject: Flattened one-side M:N fails wildly with SharedEC
>
> Hi there,
>
> just have bumped into another weird (at least to me) behaviour.
>
> In my model, there used to be a very standard M:N relationship, which
> exploits an “invisible” intermediate table, flattened “direct” relationships
> ad both sides.
>
> One of the sides lately went to the sharedEC; thus I made sure to delete this
> side's flattened relationship. The other side and the intermediate table both
> stay outside of the sharedEC, so I thought that is all right.
>
> It failed miserably with “The shared context recently initialized the object
> <non-shared-one> which is already registered in this context yadda yadda”,
> i.e., EOF for some godforsaken reason kept loading the non-shared object (the
> one whose relationship remained intanct) into SEC along with the shared one
> (whose relationship were removed all right, no traces remained; I have
> checked about zillion times).
>
> Out of desperation, I have just tried to remov the flattened relationship
> from the non-shared side, exposing instead the intermediate table, and
> replacing the flattened relationship by something like
>
> ===
> List availablePrototypes { // this is how the original flattened rel has
> been named
> def mn=this.db_Prototype_DataBlock // 1:N relationship to the
> intermediate table, exposed
> mn.collect {
> it.valueForKey('prototype') // N:1 relationship from the inmdt
> table to the shared object
> }
> }
> ===
>
> and it seems to work all right :-O So, it looks like the culprit was the
> existence of the flattened rel with definiton
> “db_Prototype_DataBlock.prototype” at the non-shared side.
>
> Is that the intended behaviour? Seems pretty weird to me, but as always, I
> might be overlooking something of importance. Or should that work even with
> the flattened relationship, and the problems mean I must have done something
> wrong elsewhere?
>
> Thanks and all the best,
> OC
>
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