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Re: EOF being overly helpful.
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Re: EOF being overly helpful.

  • Subject: Re: EOF being overly helpful.
  • From: Owen McKerrow <email@hidden>
  • Date: Tue, 20 Sep 2005 14:08:09 +1000

On 20/09/2005, at 1:32 PM, Chuck Hill wrote:


On Sep 19, 2005, at 8:08 PM, Owen McKerrow wrote:


Hi Chuck,

I had thought about and tried the batch fault thing, but its grayed out for that relationship. i.e. for the PersonName -> Person relationship I can not set a batch fault value. Any ideas why this would be ?


I'm sleepy now, so not the clearest. Relationship batch faulting probably only works on to-many. 

I think that may be the case, yes.

Try setting it on the Person entity and see if it works there.

Yup I can set a batch fault going this way but that doesn't help the problem.




And I had also added person as pre-fetch path, but it still executes the SQL as below i.e. firing the faults one at a time. Again any ideas why this is ?


No, that should not happen. Could be something in the model messed up, confusing EOF about which is which entity. Are you using inheritance?


Yup using single table inheritance. Person inherits to Staff, Student and External. Difference is defined by value of type. Could this effect it and if so how ?

There is some place (in our frameworks and in Project Wonder too), 

sorry your frameworks ? can we get copies of those ? where from ?


a delegate that will log a stack trace for each fetch. That might shed some light. 






Chuck




On 20/09/2005, at 12:53 PM, Chuck Hill wrote:



Owen,

What you are missing is a batch fetch (fault) on the PersonName - > Person relationship. You don't have one, so it defaults to one at a time. Sloooow. But I gather you have gotten that point. :-) The 167 row fetch is EOF turning the array fault (one object) into an array of faults (many objects). The subsequent one at a time fetches are the faults firing with a lack of a batch faulting setting.

Or, just add a pre-fetching path the fetch spec and fetch them all in one swell foop.

Chuck

On Sep 19, 2005, at 6:30 PM, Owen McKerrow wrote:




Hi All,

I have a table called Person which has a to-many relationship with a table PersonName, which is an optional relationship and Own's Desition is ticked and has a Batch Fault of 5.
The inverse relationship from PersonName to Person is to-one and mandatory. PersonName has its own primary key.
The idea here being a Person's name may change over time and this way I can track when that happens and any records which they entered before the name changed will still have the old name associated with it.
I have a fetch spec in PersonName which I use to get a list names of members which are currently active.
The fetch spec is :
active = 1 and person.accessLevel <> -1 and ( person.type = 2 or person.type = 3 )

Where active indicates its a currently active name, person.accessLevel <> -1 indicates the person is not inactive and person.type 2 & 3 indicates I only want the staff and students.

selectablePersons = (NSMutableArray) EOUtilities.objectsWithFetchSpecificationAndBindings (ec,"PersonName","getActiveMembers",null);

Now this works fine, it retrives all the records I want in 1 hit.
And produces the following SQL

[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT DISTINCT t0.active, t0.creationDate, t0.firstName, t0.initial, t0.lastName, t0.personID, t0._rowid FROM PERSON_NAME t0, PERSON T1 WHERE (t0.active = ? AND T1.accessLevel <> ? AND (T1.type = ? OR T1.type = ?)) AND t0.personID = T1._rowid ORDER BY t0.lastName ASC, t0.firstName ASC" withBindings: 1:1(active), 2:-1(accessLevel), 3:2(type), 4:3(type)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 167 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction

Not 167 records processed.
However it then grabs all 167 people objects associated with these names, 1 AT A TIME ! Well at least thats what I think its doing. Heres a selection of the SQL that it produces. This is all from the single line of code above.

[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.countryID, t0.email, t0.fileName, t0.filePath, t0.hasFile, t0.institution, t0.onPayroll, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:4(type), 2:1332 (rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:3(type), 2:1332(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.casualPermant, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:2(type), 2:1332(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> fetch canceled
[2005-09-20 11:20:04 EST] <WorkerThread3> 1 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.countryID, t0.email, t0.fileName, t0.filePath, t0.hasFile, t0.institution, t0.onPayroll, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:4(type), 2:980 (rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:3(type), 2:980(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.casualPermant, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:2(type), 2:980(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> fetch canceled
[2005-09-20 11:20:04 EST] <WorkerThread3> 1 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.countryID, t0.email, t0.fileName, t0.filePath, t0.hasFile, t0.institution, t0.onPayroll, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:4(type), 2:999 (rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:3(type), 2:999(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> 0 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> === Begin Internal Transaction
[2005-09-20 11:20:04 EST] <WorkerThread3> evaluateExpression: <com.webobjects.jdbcadaptor.OpenBasePlugIn$OpenBaseExpression: "SELECT t0.academicGeneral, t0.accessLevel, t0.brandNewRecord, t0.building, t0.casualPermant, t0.countryID, t0.email, t0.fax, t0.fileName, t0.filePath, t0.hasFile, t0.onPayroll, t0.phone, t0.room, t0._rowid, t0.staffNumber, t0.title, t0.tobeShown, t0.type, t0.URL, t0.wumpusID FROM PERSON t0 WHERE (t0.type = ? AND t0._rowid = ?)" withBindings: 1:2(type), 2:999(rowID)>
[2005-09-20 11:20:04 EST] <WorkerThread3> fetch canceled
[2005-09-20 11:20:04 EST] <WorkerThread3> 1 row(s) processed
[2005-09-20 11:20:04 EST] <WorkerThread3> === Commit Internal Transaction

Notice how some request produce 0 rows processed and for those that have 1 row processed the fetch is canceled. Suffice to say this is all cause a very large waste of time which means my page takes 4 seconds to load.

I thought perhaps if the to-one relationship between PersonName and Person was optional instead of mandatory it wouldn't try and grab the People records but it still did.

So what am I doing wrong ? I understand EOF is trying to be helpful and grab the People objects for me but this time I don't want it to. In fact Im not even sure what's causing these faults to be fired. If I can't "turn it off" is there any way I can get it to do it all in one go instead of object by object. And why does it cancel the fetch when it actual gets a result ?

As always comments and suggestions welcome.

Owen McKerrow
WebMaster, emlab
http://emlab.uow.edu.au

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Owen McKerrow
WebMaster, emlab
http://emlab.uow.edu.au

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Unnamed - an introduction to web applications using WebObjects and Xcode http://www.global-village.net/wointro

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






Owen McKerrow
WebMaster, emlab
http://emlab.uow.edu.au

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"As of tomorrow, employees will only be able to access the building using individual security cards. Pictures will be taken next Wednesday employees will receive their cards in two weeks."
- "Dilbert Quotes" Winner, Fred Dales, Microsoft Corp


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 >Re: EOF being overly helpful. (From: Chuck Hill <email@hidden>)






    

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