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From:Frazer Clement Date:September 12 2009 1:00am
Subject:Re: Problems with C-API client using NDB tables
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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