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Message Posted: Thu, 06 Mar 2008 @ 11:08:17 GMT


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Subj:		Re: ODBC Connect to Teradata

From:		Victor Sokovin

When we check disable Parsing and disable Prepare we can avoid this time frame when something happening within the ODBC. The statement got send right away to the DB System. But now we get the error that the maximum SQL request size of 1MB has exceeded even though the request has only 180KB. Anyway in the ODBC Documentation we found that the Statement of a DML has a max of 64K while a DDL has a max which is different (at least higher).

My documentation suggests (ODBC User Guide, ca. 2006) that 1MB is possible for the entire "array request" but the array is used to store not only the SQL statement but also what they call "parameter rows".

Some conditions is N * (T + R)<= 1MB, T + N * R <= 1MB

where

N stands for the number of parameter rows;

R - the size of a parameter rows;

T - the size of the SQL statement.

Not knowing the number and size of your parameter rows I can't say for sure whether these conditions are satisfied but I would guess that they probably should be as T in you case is just 180K so it is difficult to imagine that there would be so many parameters.

More likely you hit other limitations listed in the Guide:

N * R <= 64 KB

R <= 64 KB

I'd say try and inspect the tracing logs to find out more details on the "parameters" with parsing disabled.

Also there is still the fact that it works if whe unchecked the parsing and preparing parameter it just takes much longer, also on BTEQ using CLI we have no problem at all.

The latter confirms that ODBC extensions are not used.

Try also to compare "parameter rows" in case ODBC parsing is enabled.

Is there somehow a workaround to send bigger SQL Statements to the DB via ODBC? Does ODBC for Unix systems provide this 'feature'. What about install additional tools which could support to extend the Size of a SQL statements maybe an additional 'plug-in' which emulates this?

I forget which driver version you are using. 2006 and higher should support this and the documentation does not specify any additional restrictions for the "parsing disabled" cases so if the "parameter rows" inspection does not reveal any suspects this case can be submitted as a bug.

Victor


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