Re: Degradation of performance when upgrade psqlodbc to 09.03.0400

Hi,

Thanks for prompt response sir.

>> On 04/02/16 16:54, Dang Minh Huong wrote:
>> I'm using psqlodbc version 09.00.0310 for my project. Recently i tried to upgrade to version 09.03.0400 and found that it is very slow in processing my batch (batch with milion of SELECT, UPDATE, INSERT statements).
>>
>> [environment]
>>
>> OS: Redhat 6.7 x 2 nodes
>>
>> PostgreSQL 9.1.19: Synchronouse Streaming replication & hot_standby.
>>
>> DB connect method: psqlodbc/unixODBC.
>>
>> [results of performance]
>>
>> It took below timing to execute my batch
>>
>> In version 09.00.0310: 11minute
>>
>> In version 09.03.0400: 53minute
>>
>> When my batch run in 09.03.0400, ps command repeatedly show below processes.
>>
>> Something delay the transmitting & replaying WAL in STANDBY db node?
>>
>> -----
>>
>> ... UPDATE waiting for 0/xxx
>>
>> or
>>
>> ... INSERT waiting for 0/yyy
>>
>> ------
>>
>> Note that, my replication connection is working well, and above messages just display within a second. This phenomenon is not reproduced in version 09.00.0310.
>>
>> I have confirmed release note. I thought changing of UseServerSidePrepare's default value made this perfomance problem but not. I don't know what change make it slower.
>>
>> Sorry for lack of infomation but, is any big changes related to performance between above versions?
>
> I don't recall anything relevant. It seems strange that changing the ODBC driver would make any difference to the replication.

I also think that. I wonder if something missed in my environment but not found, and it is not reproduced in 9.00.0310.

> Something to do with autocommit, perhaps?

Sorry but did you mean that, default of autocommit was changed to "on", between above versions?

Thanks and best regards,
bocap.

>
> - Heikki
>