CBO in 10g
- From: BP <brian.peasey@xxxxxxxxx>
- To: Oracle-L <oracle-l@xxxxxxxxxxxxx>
- Date: Thu, 13 Oct 2005 22:43:16 -0500
Hi Guys,
I received this today from one of our developers, who in turn got it
from Progress. Is this true? I thought CBO was default starting in 8i
and in 10g stats are automatically collected.
N.B. 'Dataserver' is their product used to translate progress code to SQL.
Brian Peasey
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==========================================
Be careful of Oracle 10g:
A) the default optimizer under 10g is now Cost-Based (CBO); it used to
be Rules-Based (RBO) under 9i. If your database statistics aren't up to
date then the CBO can easily choose table scans. We are in the process
of writing a whitepaper on this and it should available via PSDN soon
(use the above hyperlink).
Anyone on OpenEdge 10 against Oracle 10g should get the latest OpenEdge
service pack as there was an issue related to Function Based Index usage
that could cause unnecessary Table Scans.
B) Try to upgrade to at least Oracle 10g (10.1.0.4) - there is an Oracle
bug that intermittently generates an Oracle 600 error
Simon Epps
DataServer Product Manager
Progress Software
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