Does anyone have any experience with the IBM ODBC Driver for Linux and it might also behave like this and ignore the where clause? We don't have an issue with speed with incoming ODBC requests from this linux application but they do have a big CPU hit when they run. Up to 40-50% when running. And building indexes to try and help has not.
-----Original Message-----
From: MIDRANGE-L [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Vernon Hamberg
Sent: Thursday, July 09, 2015 1:16 PM
To: Midrange Systems Technical Discussion
Subject: Re: Speeding up ODBC
Yup - in talking with one of our SQL Server folks, he said that things like SQL Server will take a statement like that and basically do a SELECT * FROM TABLE on the remote server - no WHERE clause is passed along.
Then they do the filtering on the client. Crystal Reports was/is like that, too - one was encouraged in CR to turn on a setting to force the whole query to run on the remote server.
The behavior of running SELECT * with no selectivity is a well-known one, according to Rick, the guy I talked to.
The statement inside openquery() has to be in the syntax of the remote server - no problem for you, seems you're handling both sides.
I realize I might be repeating some of what was said in that other recent thread - but this is good stuff to know and understand. And not something we'd expect.
Thing is, these clients assume least-common-denominator on this stuff - and with ODBC you can use a "standard" syntax for everyone.
Anyone know, is there a similar issue with JDBC?
Vern
On 7/9/2015 12:04 PM, rob@xxxxxxxxx wrote:
That made an amazing difference. It changed a query against a +1m row
table from "never completing" into subsecond response.
Rob Berendt
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