Re: Oracle SQL Cancel

From: The Flash <flash_at_mysite.com>
Date: 1996/10/26
Message-ID: <3272BEE0.76FE_at_mysite.com>#1/1


Tim Nickason wrote:
> We are currently use Oracle 7.3 on Dec Alpha Unix. To access the
> database we use a olap query tool called Dss Agent. We are experiencing
> a problem in that when users try to cancel a query (in Dss Agent). The
> Oracle database does not seem to heed. To make a long story short...
> Microstrategy claims the problem is that Oracle doe nor support
> SQL Cancel.
>
> Question: What is SQL Cancel? Is it an ODBC call?

Tim,
I'm not a programmer, but the problem you mention occurs with every query tool that talks to Oracle via SQL*Net. What you're looking for is often referred to as "asynchronous cancellation". The problem with SQL*Net to date is its synchronous nature: Once a query has been sent off to the server, there can be no further communication between the client and Oracle until the SELECT has completed -- at which time control is returned to the client. This also means that the client cannot send a 'cancel' to the server before the query has completed processing. It is also the reason for the infamous "locked PC" while queries are processing -- the only solution for which is the '3-fingered salute' (reboot).

As I understand it, this is primarily a function of the API (middleware) being used -- SQL*Net in this case. Other APIs, like Sybase/MS DBLIB, do permit cancellation. Furthermore, I understand that the new version of SQL*Net (2.1?) does permit asynch cancellation -- but many query tools still won't support it until they've been modified to allow cancels with Oracle.

Am sure there are more technical readers that can clarify the specifics better than I can, but this is basically the situation.

Rob Vonderhaar
Speedware Corporation
Reston, VA Received on Sat Oct 26 1996 - 00:00:00 CEST

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