Re: Index performance

From: Joel Garry <joelga_at_rossinc.com>
Date: 1996/11/12
Message-ID: <1996Nov12.180952.29478_at_rossinc.com>#1/1


In article <32836952.431A_at_ibm.net> Asaf Shoval & Yael Stoya <shovala_at_ibm.net> writes:
>Naren Chintala wrote:
>>
>> Hi,
>>
>> I hope someone can help me out here.
>>
>> Scenario 1:
>> -----------
>> CREATE INDEX idx1 ON t1(c1,d1);
>> where c1 is varchar2
>> and d1 is a date field.
>>
>> Scenario 2:
>> -----------
>> CREATE INDEX idx2 ON t2(n1,n2);
>> where n1 and n2 are numeric fields.
>>
>> Question:
>> ---------
>> Please note that the concatenated index is a combination of different
>> data types in scenario 1 and the data types are same in scenario 2.
>>
>> Will a query (that uses the concatenated index) be faster in scenario 1
>> or scenario 2 or will be the same?
>>
>> Oracle 7.2.3
>> Solaris 2.5
>>
>> Thanks in advance for any pointers.
>> Please email your response also.
>>
>> Naren Chintala
>> naren_at_mink.att.com
>
>
>1. use TKPROF and Examine the resaults after running two querys.
>2. It looks like phase 2 will be faster.

Why is that? Oracle would have to internally convert both parts of scenario 2 for each access, but only one part of scenario 1, right?

>
>Asaf shoval.

-- 
Joel Garry               joelga_at_rossinc.com               Compuserve 70661,1534
These are my opinions, not necessarily those of Ross Systems, Inc.   <> <>
%DCL-W-SOFTONEDGEDONTPUSH, Software On Edge - Don't Push.            \ V /
panic: ifree: freeing free inodes...                                   O
Received on Tue Nov 12 1996 - 00:00:00 CET

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