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From:Frazer Clement Date:September 14 2009 9:11pm
Subject:Re: Problems with C-API client using NDB tables
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Matthew Schlegel wrote:
> Hi Frazer,
>
> It looks like the Users application is running correctly using the ndb with order by
> this time.   It's possible that their first attempt using the order by statements may not
> have been a complete compile, which may be what caused the problems they had seen with
> that configuration before.
>
> Thank you for the assistance in brainstorming a couple ideas to work with given very
> little information.   These kinds of problems are a pain to track down sometimes.
>
>   
Great news!
> Thank you,
>
> Matthew Schlegel
> System Analyst
>
> eXcellence in IS Solutions, Inc. (X-ISS)
> Office:  713.862.9200 x203
> http://www.x-iss.com
>
> Making IT Work for You 
> HPC & Enterprise IT Solutions
>
>
>
> -----Original Message-----
> From: Frazer.Clement@stripped [mailto:Frazer.Clement@stripped] 
> Sent: Friday, September 11, 2009 20:00
> To: Matthew Schlegel
> Cc: cluster@stripped
> Subject: Re: Problems with C-API client using NDB tables
>
> Matthew Schlegel wrote:
>   
>> Hi Frazer,
>>
>> Per the User, they are not receiving any errors from the server or the client -
> there does not seem to be any timeout or performance issues involved at this point.
>>
>> Row-ordering is a possibility.  I had the User add 'order by' clauses to the
> appropriate queries, and while the database tables looked like the application had started
> working, the User reports that it wasn't working.    I asked the user to rerun the
> following combinations.
>>
>> * myisam w/o order by
>> * myisam with order by
>> * ndb w/o order by
>> * ndb with order by
>>
>> Hypothetically, if the application works in the 'MyISAM with order by' case, but
> doesn't work in the 'ndb with order by' case, what might cause that behavior?
>>     
> Sounds like a good approach.
> Perhaps there's an assumption about the ordering that is not 
> encapsulated by the Order by - e.g. if Order by is not on unique values 
> then there's some scope for different ordering  between multiple rows.  
> MyISAM would probably return entry sequenced rows, Ndb would return 
> pseudo-random sequenced rows.
> I realise that you're working with limited information, but it's much 
> more efficient to identify the problem with a known deviation from 
> expected behaviour. 
>   
>> Thank you for the assistance,
>>
>> Matthew Schlegel
>> System Analyst
>>
>> eXcellence in IS Solutions, Inc. (X-ISS)
>> Office:  713.862.9200 x203
>> http://www.x-iss.com
>>
>> Making IT Work for You 
>> HPC & Enterprise IT Solutions
>>
>>
>>
>> -----Original Message-----
>> From: Frazer.Clement@stripped [mailto:Frazer.Clement@stripped] 
>> Sent: Friday, September 11, 2009 11:01
>> To: Matthew Schlegel
>> Cc: cluster@stripped
>> Subject: Re: Problems with C-API client using NDB tables
>>
>> Matthew Schlegel wrote:
>>   
>>     
>>> Howdy,
>>>
>>>  
>>>
>>> I have a basic 2-node NDB cluster setup running 
>>> 5.1.34-ndb-7.0.6-cluster-gpl-log. The cluster is setup with 2 data 
>>> nodes, 2 mgmt nodes, and 2 API nodes. 
>>>
>>> We are working to migrate a user application using the C-API (v14.7 
>>> distribution 4.1.12) from using a MySQL server version 
>>> 5.0.40-enterprise to using the cluster, however, the user is reporting 
>>> problems with their application when the storage engine is changed to 
>>> NDB. The application is reported to work properly when connected to 
>>> the clusters API nodes using MyISAM tables. 
>>>
>>> The table causing problems is: 
>>> CREATE TABLE `test_NDB` ( 
>>> `shot` int(11) DEFAULT NULL, 
>>> `status` int(11) DEFAULT NULL, 
>>> `job` varchar(256) DEFAULT NULL, 
>>> `node` varchar(10) DEFAULT NULL, 
>>> `sdb` blob 
>>> ) TABLESPACE ts_1 STORAGE DISK ENGINE=ndbcluster; 
>>>
>>> I'm aware that the lack of indexes will affect performance, however, 
>>> the goal at this point is to get their application running. 
>>>
>>> Is there anything that would cause select queries on this table to be 
>>> returned in any way different than they would with the same queries on 
>>> a MyISAM version of the table?
>>>
>>>     
>>>       
>> Yes.
>> To progress this issue you need to indicate what sort of problems the 
>> user application is experiencing.  Performance?  Timeouts?  Row ordering?
>>   
>>     
>>> Thank you for the assistance,
>>>
>>>  
>>>
>>> Matthew Schlegel
>>>
>>> System Analyst
>>>
>>>  
>>>
>>> eXcellence in IS Solutions, Inc. (X-ISS)
>>>
>>> Office:  713.862.9200 x203
>>>
>>> http://www.x-iss.com
>>>
>>>  
>>>
>>> *Making IT Work for You*
>>> _HPC & Enterprise IT Solutions_
>>>
>>> Fast Tech email
>>>
>>>  
>>>
>>>
>>> NOTICE:
>>> This message may contain privileged or otherwise confidential information.
>>> If you are not the intended recipient, please immediately advise the sender
>>> by reply email and delete the message and any attachments without using,
>>> copying or disclosing the contents.
>>>   
>>>     
>>>       
>>   
>>     
>
>   

-- 
Frazer Clement, Software Engineer, MySQL Cluster 
Sun Microsystems - www.mysql.com
Office: Edinburgh, UK

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Thread
Problems with C-API client using NDB tablesMatthew Schlegel11 Sep
  • Re: Problems with C-API client using NDB tablesFrazer Clement11 Sep
    • RE: Problems with C-API client using NDB tablesMatthew Schlegel11 Sep
      • Re: Problems with C-API client using NDB tablesFrazer Clement12 Sep
        • RE: Problems with C-API client using NDB tablesMatthew Schlegel14 Sep
          • Re: Problems with C-API client using NDB tablesFrazer Clement14 Sep
  • Re: Problems with C-API client using NDB tablesTom Hanlon16 Sep