Re: Anyone know any WP which explains about FTS vs Index Scan?

From: Frits Hoogland <>
Date: Sat, 14 Apr 2018 17:19:16 +0200
Message-Id: <>

My question would be: why an index range scan MUST be used? What is the reason for this person to deem it mandatory?

This would also discard unique index access, which is a different access path than an index range scan.

I question the knowledge of the person if he/she can not see the point of a full table scan or any other different access path. Even if the documentation would state that an index must be used, and does not provide a valid reason for why it shouldn’t be used, I would discard the advise in the documentation. There are lots of examples where the official documentation is incorrect, and even experts might be wrong; for something to be written in a book doesn’t make it the truth.

Frits Hoogland <> <> Mobile: +31 6 14180860

> On 10 Apr 2018, at 18:13, Ls Cheng <> wrote:
> Hi
> I have a Dinosaur stating we must always use index range scan no matter OLTP or DWH systems. This guys still lives in the late 90's and Oracle 7 (although he claims he is 18 years veteran expert from 7 up to 12c), the thing is I cannot find any Oracle WP or similar in the docs which states Full Table Scan is not evil except Tom Kyte (asktom). I have even demo-ed him with a very simple two table join example with FTS and index range effect when a large amount of data need to be accessed, still he says in Oracle docs states that scattered reads (FTS) mist be reduced!
> Does anyone know any official pointer, in WP form or MOS support note which talks about FTS vs index scans?
> Cheers

Received on Sat Apr 14 2018 - 17:19:16 CEST

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