Re: Performance Problems with Ora 7.33

From: Kevin Loney <Kevin.Loney_at_astramerck.com>
Date: Thu, 5 Nov 1998 08:32:05 -0500
Message-ID: <sNh02.1545$XJ.4542534@newsread.com!newshog.newsread.com>

Most likely culprit: hash joins. In init.ora, set HASH_JOIN_ENABLED=FALSE and restart and try again. The 7.3.3 optimizer uses hash joins in place of many nested loops joins. Hash joins require full table scans, so that can impact your performance. Try turning off that feature and see what happens.

As a further test, you could go to 7.3.2.3 instead of 7.3.3, since hash joins weren't enabled by default until 7.3.3.

hth.
Kevin
http://www.kevinloney.com

Uwe Schneider wrote in message <36419371.ED5B3F7E_at_xlink.net>...
>Hi,
>
>after finally finished upgrading from Oracle 7.23 to 7.3.3 we
>are experiencing dramatical performance decays with queries, esp. with
>complex joins which used to run flawlessly.
>
>This means e.g. that some programs which used to finish in 10 seconds
>now run for hours (with full cpu contention on the server). Other
>programs even trigger a timeout and don't even work anymore.
>
>Can somenody give me a hint what we can do, or what we could have done
>wrong?
>
>(After upgrading the server software I did upgrade the database objets.)
>
>In deperate mood
>
>Uwe
Received on Thu Nov 05 1998 - 07:32:05 CST