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From:Matthew Schlegel Date:September 14 2009 8:38pm
Subject:RE: Problems with C-API client using NDB tables
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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.

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

Are you MySQL certified?  www.mysql.com/certification


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.


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