MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

Connectivity

MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

Hi Folks,
I'm using a .NET Data provider version [01.02.00.00] for Teradata. I'm using connection pooling feature which is being provided by the data provider. Once i start using my web based application, as the number of users start using system concurrently at some point of time application throws the below given exception.

As a developer i'm not able to come to a conclusion, what the problem would be ?
Any help will be appreciated.

Regards,
Rahul Pawar.
6 REPLIES
Teradata Employee

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

Provider does not receive a response from Teradata Database within the specified TIMEOUT period.

DbCommand (TdCommnad) has a default timeout: [url=http://msdn2.microsoft.com/en-us/library/system.data.common.dbcommand.commandtimeout.aspx]DbCommand.CommandTimeout
[/url]

TdCommand defaults to 30 seconds before it aborts the query and returns the error.

One solution is to increase the command timeout; another is to investigate the overall responsiveness your system under load.

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

Thanx for your reply.
I have specified CommandTimeout = 180 seconds.

Is the issue with connection pooling ?
Application uses .NET framework 2.0, though application closes a connection through the code it is not guaranteed that i will immediately return to the pool. Hence if i set performance counters, there are some connections which are getting leaked out ( means number of connections and number of pooled connections never match.

Some clarity on this will be helpful.

Teradata Employee

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

I do not think it is related to Connection Pooling. Connection (DbConnection) has a separate Timeout value. In another word, the process of "opening" a connection is separate and distinct from the process of executing a Command. The fact that Command times out indicates that Provider does not receive a response from Teradata database to one of the Execute methods. I suggest looking at the overall end-to-end performance under load; starting with Teradata database.

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

thanx shaw for your prompt reply.
Just FYI.
Yesterday i had obeserved that Teradata's window service "disstart.exe" was consuming almost 50% of cpu cycles for each query which application fired on Teradata. similarly memory usage was also quite high.
Can you please throw some light on this issue.

One more question.
The same web based product runs on SQL Server without any timeout issues. I have heard that we can do parallel processing to Teradata queries ( Not sure).. Is there some configuration or a setting which will increase my end -to - end response time. My application has a table which is almost used by all the queries to Update/add/delete entries. Think so this can be a bottle neck ( or a deadlock type of situation) .. Still investigating on this.

Regards,
Rahul Pawar.
Teradata Employee

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

I cannot answer your question about CPU utilization without additional information.

However Teradata Database was designed from ground up as a data warehouse; SQL Server was designed as an OLTP. Therefore there will be differences when it comes to UPDATE strategy. Teradata has numerous tools to help you with Performance analysis; you should start by looking at Teradata Manager User Guide.

Re: MTDP: EM_TIMEEXCEEDED(245): Timeout from DBCHWL.

thanx shaw.
Will come back to you as soon as i'm done with my detailed investigation.

Regards,
Rahul Pawar.