Re: The Cost Based Optimizer drives me crazy...

Chuck Hamilton (chuckh_at_dvol.com) wrote:
: "Medscheme" <esmev_at_medscheme.co.za> wrote:
 

: >Help me to explain this:
: >
: >We have a 7.3 database running on NT.
: >
: >This statement (an example) makes use of the index on column1:
: >
: > Select * from table A where column1='xxxx'
: >
: >This statement does NOT make use of the index on column1:
: >
: > Insert into table B (select * from table A where column1='xxxx')
: >
: >Why would this happen?
: >
: >Esmé Venter
: >esmev_at_medscheme.co.za
: >
 

: Because the CBO is not real good yet. Try giving it a hint to force it
: to use the index.
 

: insert into table b
: (select /*index(a)*/ * from table a where column1 = 'xxxx');

I think you need a + on the hint
 (select /*+ index(a)*/ * from table a where column1 = 'xxxx');

: --
: Chuck Hamilton
: Sr. DBA
: Keystone Mercy Health Plan
: chuckh_at_dvol.com
 

: "So teach us to number our days that we may present to thee a heart of wisdom"
: (Psalm 90:12 NASB)

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