Re: [Wonder-disc] Batch deletions

[Chuck H. <ch...@gl...>]

On Apr 17, 2009, at 10:31 AM, Dan Grec wrote:
> On 17-Apr-09, at 11:13 AM, Chuck Hill wrote:
>> On Apr 17, 2009, at 10:06 AM, Dan Grec wrote:
>>
>>> Hey all,
>>>
>>> So we're still kicking this idea around, and my brain won't let it  
>>> rest.
>>>
>>> We're a little afraid of using the ERXEOAccessUtilities apprach as  
>>> we really don't want to deal with the object graph being in a  
>>> funny state.
>>
>> Your object graph probably already gets in funny states.  Running  
>> multiple instances?  Not using the Wonder EO change sync  
>> framework?  Ever get odd error reports that you can't reproduce?
>
> Hmm - we do have multiple instances, but we are running Wonder EO  
> change stuff. From time to time we do get  
> EOObjectNotAvailableException and similar that are strange.

You might have your answer there.  ;-)


>>> So I've been wondering if we can influence the SQL that is  
>>> generated  when EditingContext.saveChanges() is called.
>>> At that point, all the notifications have been sent out and all of  
>>> that stuff.
>>> So when it creates the SQL for deletedObjects, instead of going  
>>> over each EO one at a time and making "delete from foo where id=bar"
>>> could it possibly check to see if there are many EOs of the same  
>>> class and making a "delete from foo where id in "bar,bar2,bar3"  
>>> type of dealy-o.
>>> I also understand that it needs to visit each EO one at a time to  
>>> call things like EO.willDelete() on them, I'm wondering if it  
>>> could do all that, then make the one line of SQL and run it...
>>> I'm going as deep as I can with Jad, but I'm way over my head.
>>>
>>> It seems like a pretty nice optimization to me.
>>>
>>> Is this possible or am I completely off base?
>>
>> Probably possible, but really, really difficult.  You'd need to  
>> subclass and replace some classes way down in EOAccess.
>
> Nice to know that one day I might be able to do it.
> If the multi row delete failed there might be problems....
>
> Now I'm thinking we can still use  
> ERXEOAccessUtilities.deleteRowsDescribedByQualifier and then just  
> mark those EO's to be refaulted.  Thoughts?

I think you would want to invalidate them.  BUT that will only help  
for the instance they are deleted in.


Chuck


>>
>> Chuck
>>
>>
>>> On 16-Apr-09, at 12:08 PM, Chuck Hill wrote:
>>>
>>>>
>>>> On Apr 16, 2009, at 6:30 AM, Vaughan Van Der Merwe wrote:
>>>>
>>>>> So if we happen to be using multiple instances as well as a  
>>>>> 'Wonder
>>>>> cross-instance synching thingy' we could potentially end up in a
>>>>> weird state by using this?
>>>>
>>>> I think a more correct statement would be that the 'Wonder cross-
>>>> instance synching thingy' eliminates (or at least greatly reduces)
>>>> weird states and using this can bring them back.  If you are not  
>>>> using
>>>> it, you have to deal with the weird states.  Or, as I suspect most
>>>> people do, just not worry about them.
>>>>
>>>> Chuck
>>>>
>>>>
>>>>>
>>>>>
>>>>> On 15-Apr-09, at 4:34 PM, Chuck Hill wrote:
>>>>>
>>>>>>
>>>>>> On Apr 15, 2009, at 3:07 PM, Mike Schrag wrote:
>>>>>>
>>>>>>>> Wonder's ERXEOAccessUtilities is what you want.  This  
>>>>>>>> bypasses all
>>>>>>>> the
>>>>>>>> EOF validations and delete rules as well, so be aware of that.
>>>>>>> and leaves your object graph in an inconsistent state, so you  
>>>>>>> need
>>>>>>> to
>>>>>>> manually refresh it ...
>>>>>>
>>>>>> Or just not worry about it. :-) If you are running multiple  
>>>>>> instances
>>>>>> and not using the Wonder cross-instance synching thingy, then  
>>>>>> this is
>>>>>> the same situation as EOF processing the deletes in another  
>>>>>> instance.
>>>>>>
>>>>>>
>>>>>> Chuck
>>>>>>
>>>>>>
>>>>>> -- 
>>>>>> Chuck Hill             Senior Consultant / VP Development
>>>>>>
>>>>>> Practical WebObjects - for developers who want to increase their
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>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>>>
>>>>>
>>>>>
>>>>
>>>> -- 
>>>> Chuck Hill             Senior Consultant / VP Development
>>>>
>>>> Practical WebObjects - for developers who want to increase their
>>>> overall knowledge of WebObjects or who are trying to solve specific
>>>> problems.
>>>> http://www.global-village.net/products/practical_webobjects
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
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>>
>> -- 
>> Chuck Hill             Senior Consultant / VP Development
>>
>> Practical WebObjects - for developers who want to increase their  
>> overall knowledge of WebObjects or who are trying to solve specific  
>> problems.
>> http://www.global-village.net/products/practical_webobjects
>>
>>
>>
>>
>>
>>
>
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-- 
Chuck Hill             Senior Consultant / VP Development

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