Re: fetchLimit don't affect SQL fetching limit?
Re: fetchLimit don't affect SQL fetching limit?
- Subject: Re: fetchLimit don't affect SQL fetching limit?
- From: Henrique Gomes <email@hidden>
- Date: Wed, 27 Jun 2012 14:23:27 +0100
Also,
I had trouble some time ago, because a fetch *was* using LIMIT (on Postgres) but the subsequent fetch of prefetchingRelationshipKeyPaths were NOT.
Is that expected behavior? I assume so, the result of LIMITing the fetch might not bring the relation tuples corresponding to the initial LIMITed fetch. Right?
HG
On Jun 27, 2012, at 12:55 PM, Kieran Kelleher wrote:
> Also, you can verify by checking the SQL that is being sent to the database rather than just guessing that LIMIT is not being applied. It might be a big relationship that is causing OOM exception. Or maybe you have not allocated enough memory to your app.
>
> On Jun 27, 2012, at 7:52 AM, Kieran Kelleher wrote:
>
>> LIMIT is supported by the Wonder MySQL PlugIn since Nov 22, 2011, commit 6c511bb. You would need the MySQLPlugIn in your build path.
>>
>>
>> On Jun 27, 2012, at 3:13 AM, Gennady Kushnir wrote:
>>
>>> I assumed that (
>>> How can I force LIMIT to SQL statement in MySQL?
>>>
>>> 2012/6/26 Kieran Kelleher <email@hidden>:
>>>> It depends on the database plugin you are using. Some plugins take the fetchSpec fetchLimit and incorporate it into the SQL statement in the plugin's EOSQLExpression subclass. The default behaviour of EOF is to limit in memory after the fetch.
>>>>
>>>> On Jun 26, 2012, at 10:23 AM, Gennady Kushnir wrote:
>>>>
>>>>> Hello all!
>>>>> I am fetching from a table that has lots of records. So I decided to
>>>>> fs.setFetchLimit(10) on my EOFetchSpecification, but nevertheless when
>>>>> I perform ec.objectsWithFetchSpecification(fs) I get
>>>>> JavaOutOfMemoryError.
>>>>> It seems to me that fetchLimit does not actually convert to a LIMIT
>>>>> clause in a SELECT statement in underlaying SQL. So the actual
>>>>> limitation is made in memory after fetch.
>>>>> Is it a conventional behavior or it is me doing something wrong?
>>>>>
>>>>> Gennady
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>>>
>>> --
>>> С уважением,
>>> Геннадий Кушнир
>>
>
>
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