Re: function based indexes

From: Tim Gorman <tim_at_sagelogix.com>
Date: Thu, 12 Aug 2004 19:21:06 -0600
Message-ID: <BD4173A2.1A271%tim@sagelogix.com>

The setting of the parameter QUERY_REWRITE_INTEGRITY has no bearing on anything but query rewrite in materialized views...

SQL> create index initcap_ename on emp(initcap(ename)) compute statistics;

Index created.

SQL> show parameter rewrite

NAME                        TYPE        VALUE
--------------------------- ----------- ---------------
query_rewrite_enabled       string      TRUE
query_rewrite_integrity     string      STALE_TOLERATED

SQL> set autotrace traceonly explain
SQL> select ename from emp where initcap(ename) = 'Smith';

Execution Plan

0 SELECT STATEMENT Optimizer=CHOOSE
1 0 TABLE ACCESS (BY INDEX ROWID) OF 'EMP' 2 1 INDEX (RANGE SCAN) OF 'INITCAP_ENAME' (NON-UNIQUE) The hoops to be jumped through to enable FBI are:

COMPATIBLE >= 8.1.0
OPTIMIZER_MODE <> rule
QUERY_REWRITE_ENABLED = true
QUERY REWRITE or GLOBAL QUERY REWRITE permission granted
CBO statistics gathered on the index

Hope this helps...

-Tim

on 8/11/04 8:20 PM, Mohammed Shakir at mshakir08816_at_yahoo.com wrote:

> I had to do the following to get function based indexes working.
> But I have Oracle 9i. You can check 10g documentation to confirm.
>
> You must have the following initialization parameters defined to create
> a function-based index:
>
> QUERY_REWRITE_INTEGRITY must be set to TRUSTED
>
> QUERY_REWRITE_ENABLED must be set to TRUE
>
> COMPATIBLE must set to 8.1.0.0.0 or a greater value
>
>
> Shakir
>
>
> --- Harvinder Singh <Harvinder.Singh_at_MetraTech.com> wrote:
>

>> Hi,
>> 
>> We are creating function based indexes and have question about parameter
>> query_rewrite_integrity. Docs says value for this parameter should be
>> trusted to be able to use FBT but even when I set this parameter setting
>> to ENFORCED, optimizer is able to use index. So what should be the value
>> of this parameter to be able to use function based indexes?
>> We are using 10g on red hat linux
>> 
>> Thanks
>> --Harvinder

>
>
> =====
> Mohammed Shakir
> CompuSoft, Inc.
> 11 Heather Way
> East Brunswick, NJ 08816-2825
> (732) 672-0464 (Cell)
> (732) 257-6001 (Home)

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Received on Thu Aug 12 2004 - 22:21:57 CDT