Re: CBO stupid !!!

From: David <darussell_at_msn.com>
Date: Sat, 30 May 1998 21:44:51 +0100
Message-ID: <egDKGwAj9GA.143@upnetnews05>

Many of the reasons for Full Table scans are caused because of the lack of Histograms in 7.2, I would recommend 7.3.x which include many new plan options, STAR, HASH JOIN and HISTOGRAMS.......

Regards
David Russell

Keith Boulton wrote in message
<356fe5d7.11822161_at_read.news.global.net.uk>...
>On Sat, 30 May 1998 10:35:32 GMT, eis_at_mail.otenet.gr wrote:
>
>>
>> Hi,
>>
>> We use Oracle 7.2.2.4 on SCO UNIX 3.2.4.2. I must say we are very
>> happy Oracle users. Initially we started with optimizer mode = RULE
>> so we could migrate smoothly from Oracle 6.0.37. Then we switched
>> on the COST mode. Though generaly CBO works ok, at times it
>> makes stupid decisions!
>>
>
>Setting the initialisation parameter OPTIMIZER_MODE=FIRST_ROWS may
>help. By default, CBO tends to choose full table scans
>inappropriately.
Received on Sat May 30 1998 - 15:44:51 CDT