RE: Hint for self-join connect by
- From: "Herring Dave - dherri" <Dave.Herring@xxxxxxxxxx>
- To: "John Darrah" <darrah.john@xxxxxxxxx>
- Date: Tue, 1 May 2007 15:44:56 -0500
That's good to know, John! The client told me "everything is slow"
under this patch, but so far I've only identified this CONNECT BY query
as something drastically different, in terms of performance. I found
that 9.2.0.8 with no security patch and with CPUApr2007 also yield this
poor performing plan, so I definitely need a workaround for this query.
So far initial results show a histogram on the START WITH column
(acct_id) gives me what I need. I tried indexes matching suggestions I
found on JL's web site (concerning how to tune access against
PLAN_TABLE), but while the plan picks them up, performance is the same.
Dave
___________________________________
David C. Herring, DBA | A c x i o m Delivery Center Organization
630-944-4762 office | 630-430-5988 wireless | 630-944-4989 fax
________________________________
From: John Darrah [mailto:darrah.john@xxxxxxxxx]
Sent: Tuesday, May 01, 2007 2:10 PM
To: Herring Dave - dherri
Cc: oracle-l
Subject: Re: Hint for self-join connect by
Hey Dave,
A friend of mine ran into this same problem after applying that cpu to
9.2.0.6. I'll try to get in touch with him to confirm but I believe he
ended up setting _old_connect_by_enabled to true. this fixed his
performance problem but caused the connect by to behave as it did in 8i
which may not work for your query. Don't know if this will be of any
help but I thought I'd pass it on.
John
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