Re: Anybody more familiar with "_use_old_connect_by" than I am?

On 11/06/2006 01:20:01 AM, Andre van Winssen wrote:
> Hi Carel-Jan,
>
> as pointed out by Fairlie I made a typo (copied it from Metalink SR). The
> parameter I used is called "_OLD_CONNECT_BY_ENABLED". Try that one
>
> Rgds,
> Andre

Oh boy, is this a blast from the past or what? In Oracle 9.2 mechanism for executing hierarchical queries has changed. The new mechanism relies on sort, rather then on indexes. That is why you see things like "buffer sort" in the execution plan. You will also see "buffer sort" whenever you execute analytic function. My conclusion is that Oracle is executing "connect by" in the same fashion as the analytic functions are executed. As far as I can remember, there was a vicious bug related to the parameter you mentioned. There was another undocumented parameter, with the word "siblings" in the name which I don't remember now and which would help you avoid the bug in question. I don't have 9i available here and I don't want to reboot, start Winduhs and connect to the office (VPN doesn't work on Linux) and start investigating. As a matter of fact, as of yesterday, there is no production database with the version lower then 9.2.0.8 in the company that I currently work for. I encountered this beauty in 2003.

-- 
Mladen Gogala
http://www.mladen-gogala.com

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