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

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

2006/11/6, Carel-Jan Engel <cjpengel.dbalert_at_xs4all.nl>:
>
> Hi Andre,
>
> I'm in the middle of a 'connect by' battle too. My CT is using 10.1.0.3.0.
> I tested it on my laptop on 10.2.0.1.0 with identical (problematic)
> results. A SQL statement like:
>
> SELECT CONT_NO FROM CONTAINER WHERE PARENT_CONT_NO IS NULL START WITH
> ROWID = CHARTOROWID('AAACkPAAIAAAAOXAAY') CONNECT BY PRIOR PARENT_CONT_NO =
> CONT_NO;
>
> ends up with FTS, whilst replacing the ROWID =
> CHARTOROWID('AAACkPAAIAAAAOXAAY') by CONT_NO = 100115121 made it work
> fast. It went down from 1011 to 9 consistent gets. Of course it is strange
> that accessing the starting row through PK leads to a faster result than
> accessing through rowid. Christian Antognini was able to reproduce it on
> 10.2.0.2.0, and there it worked correctly. He could reproduce on
> 10.1.0.4.0.
>
> Your post triggered me to try _use_old_connect_by on my 10.2.0.1.0database. Alas, the parameter was unsupported. We will probably decide to
> rewrite the statements (have the vendor rewriting the statements in the
> app).
>
> Best regards,
>
> Carel-Jan Engel
>
> ===
> If you think education is expensive, try ignorance. (Derek Bok)
> ===
> On Sun, 2006-11-05 at 23:24 +0100, Dree VeeWee wrote:
>
> Hello,
>
>
>
> anybody have used the setting "_use_old_connect_by" ?
> We had to use it (instance level) in our migrated 9.2.0.7 to 10.2.0.2database (win32) because certain hierarchical queries were chewing up all
> the cpu. After we set "_use_old_connect_by" to TRUE, cpu usage went back to
> normal. This suggestion was made by the metalink support analyst as one of
> many attempts to fix the cpu problem which almost brought down the oracle
> server.
> Appearantly it influences the execution of connect-by queries in 10g. But
> since Metalink doesn't have much on this setting I am not sure which
> unwanted side effects to expect (eg, wrong resultsets, influence on
> other type of queries, other bugs)
>
>
>
> Kind regards,
>
> Andre v Winssen
>
>
>
>
>
>

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