RE: A question about performance

From: Singla, Sanjeev <SSingla_at_oxhp.com>
Date: Wed, 21 Jun 2000 09:17:38 -0400
Message-Id: <10535.109978@fatcity.com>

 Full table scan will be faster.
 Reason: If it go for index scan it will get the rowids and come back with those
 rowids to scan the table because u are selecting all the columns so it has to do full
 scan of table also for getting everything.  Index scan + full scan of table for actual data. (If going for index scan)

• Only table scan for actual blocks (Full scan)

 Cheers.

-----Original Message-----
From: TiffanyDu_at_pcdc.com.tw [mailto:TiffanyDu_at_pcdc.com.tw] Sent: Tuesday, June 20, 2000 11:35 PM
To: Multiple recipients of list ORACLE-L Subject: A question about performance

	Hi All:
		There is a question about performance.
		Table  name : subscriber  , primary key : subscr_id , with

over 5000000 records .

		CASE 1 : select * 
					from subscriber ;


					(FULL TABLE SCAN)


		CASE 2 : select * 
					from subscriber
					where subscr_id > 0 ;


					(USE INDEX)


		Could anyone tell me which ones performance is better , or

they are the same ??

                Thank you in advance.                                         

Tiffany
E-mail tiffanydu_at_pcdc.com.tw                 

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  INET: TiffanyDu_at_pcdc.com.tw

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Received on Wed Jun 21 2000 - 08:17:38 CDT