Re: Re: WHERE 1 = 1 (any info on this)

You can find it a lot of codes on oracle finanacials where they used 'index supression' on perfectly indexed columns. I don't know why. That type of index supression spending 15 to 20 minutes and when it was modifed it took less than a second as column was perfectly indexed. Those codes were atleast not modified in version 10.7. There was no concept of function based indexes either as optimizer was rule based(regardless of 8i).

Regards
Rafiq

Reply-To: ORACLE-L_at_fatcity.com
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: Wed, 22 Oct 2003 02:44:25 -0800

• Original Message -----

> im assuming this is an old 'trick' from RBO days. Alot of these are still
floating around. Wasnt there one when you wanted to force a full table scan you would go
>
> where num_field = 1 + 0;
>
> the + 0 forced the full table scan? I was on a project earlier this year
and one guy told people to use it.
>

Actually, that one is still valid. Along with using any function around a predicate column. In general, an expression instead of the column name in a predicate will force ignoring of any conventional indexes on that column. Of course, function-based indexes were made just for that.

Cheers
Nuno Souto
nsouto_at_optusnet.com.au

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