Re: Stepping through the SQL Execution plan [was: WTB: Oracle Visual SQL Debugger]

From: Charles Schultz <sacrophyte_at_gmail.com>
Date: Thu, 23 Apr 2009 16:21:20 -0500
Message-ID: <7b8774110904231421v3613b61g21014794122c6d08_at_mail.gmail.com>



Hmm.... two responses with exactly the same link... I am getting a message here. =)
Thanks Wolfgang and Mark. Yes, Tanel's paper is awesome! Now I want to go sit in on his Advanced Troubleshooting seminars. *grin*

Ok, I'll settle back and start reading some more. This is good stuff.

On Thu, Apr 23, 2009 at 16:16, Wolfgang Breitling <breitliw_at_centrexcc.com>wrote:

> How about Tanel (Poder)'s os_explain:
>
> http://blog.tanelpoder.com/2008/06/15/advanced-oracle-troubleshooting-guide-part-6-understanding-oracle-execution-plans-with-os_explain/
>
> At 02:54 PM 4/23/2009, Charles Schultz wrote:
>
> After talking with some folks, it sounds like this functionality is not
> even available at present, so there are no such tools that can take
> advantage of it.
>
> Which got me to thinking. Hypothetically, how would this work? We know
> Oracle builds a query plan for the purposes of being executed in a
> particular fashion. Would it be a "trivial" matter of adding a stop check
> flag (ie, breakpoint) to the existing code? I am thinking it would have to
> be more complex than that, since the execution code must be optimized to run
> extremely fast, and having a check for each operation could potentially be
> expensive.
>
> I looked through Julian Dyke's most excellent "Internals" papers, but did
> not find any detailed information about query execution internals. Has
> anyone published anything along those lines?
>
> I blame Jonathan Lewis for getting me started down this track. *grin* His
> copious contributions to the field, and the CBO in particular, are well
> thought-out and extremely helpful, and his personality of always looking for
> the truth is infectious.
>
> On Sat, Apr 18, 2009 at 21:55, Charles Schultz <sacrophyte_at_gmail.com>
> wrote:
> Good day, list,
>
> When I was taking a C++ class in college, for a short time we had access to
> a really powerful X debugger (running on HPUX) that not only allowed one to
> step through code but depicted the state of any watched objects (variables,
> pointers, classes, etc) as a linked box with all relevant details
> (addresses, values, members, etc). I really miss that tool.
>
> Is there anything related for stepping through SQL? Not PL/SQL, mind you. I
> am looking for a tool that can show me, graphically, how access predicates
> get rowids out of an index, which are then passed up to a table access with
> a filter predicate, then passed into a nested loop operation as a driving
> rowsource which dictates the rows wanted from the 2nd child operation. I
> want to see data; which rows were gotten and why, one row at a time. I am
> sure we have all see powerpoint slides that show us this detail one painful
> click at a time, but what about a run-time tool? Direct memory attach
> programs come to mind, but they usually do not cater to the same audience
> for some strange reason (*grin*). The audiences I have in mind are in
> classroom settings, teaching Jr. DBAs and developers; I doubt any
> experienced DBA would admit to wanting something like this. But I do. =)
>
> PS - I did look around on google, but the hits were not promising. I was
> not able to find much information about Visual SQL 4.2 (seems old), nor the
> MS Visual Studio series - nothing in my quick driveby on the information
> superhighway really satisfied me.
>
> --
> Charles Schultz
>
>
>
>
> --
> Charles Schultz
> Sent from Champaign, Illinois, United States
>
> Regards
>
> Wolfgang Breitling
> Centrex Consulting Corporation
> www.centrexcc.com
>

-- 
Charles Schultz
Sent from Champaign, Illinois, United States

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Received on Thu Apr 23 2009 - 16:21:20 CDT

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