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-----Original Message-----
From: FreeLists Mailing List Manager [mailto:ecartis_at_freelists.org] Sent: Monday, August 07, 2006 11:35 AM
To: oracle-l digest users
Subject: oracle-l Digest V3 #226

oracle-l Digest Sun, 06 Aug 2006 Volume: 03 Issue: 226

In This Issue:

		ganesh-raja wants to share sites with you...
		Re: ganesh-raja wants to share sites with you...
		Re: endpoint_value and endpoint_actual_value

----------------------------------------------------------------------

Date: Sun, 6 Aug 2006 02:36:53 -0700
From: ganesh.raja_at_gmail.com
Subject: ganesh-raja wants to share sites with you...

ganesh-raja (ganesh.raja_at_gmail.com) has invited you to StumbleUpon!

You can see my other favorites here:
http://ganesh-raja.stumbleupon.com

Thanks,
ganesh-raja

---
StumbleUpon lets  you discover great sites with a
single click. Give it a try at:
http://www.stumbleupon.com/join.php?friend=464300&emailcode=nrpdnwbcw5t4ubfy




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Date: Sun, 6 Aug 2006 10:46:40 +0100
From: "David Sharples" <davidsharples_at_gmail.com>
Subject: Re: ganesh-raja wants to share sites with you...

dont spam the list with this please
On 06/08/06, ganesh.raja_at_gmail.com <ganesh.raja_at_gmail.com> wrote:


>

>

>




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Date: Sun, 6 Aug 2006 07:58:58 -0500
From: "Charles Schultz" <sacrophyte_at_gmail.com>
Subject: Re: endpoint_value and endpoint_actual_value

Thanks, that helps. Jared had mentioned you had something in your book, but
when I combed through chapters 7 and 10, I did not find it. Off by one.
*grin*
On 8/5/06, Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk> wrote:


>

>

> I missed the original conversation, I think, but:

>

> There is a pl/sql procedure in my book (CBO Fundamentals)

> that calculates the end-point value for a character string.

> The algorithm starts by taking the first 15 characters (padding

> with nulls if necessary), reading it as a hex number of 30 digits,

> converting to decimal, then rounding that decimal to 15 significant

> figures. (which is approximately the same as the value you would

> get by using just the first six bytes of the string and zero padding

> them up to 15 bytes - hence your 6-character observation).

>

> The use of endpoint_actual_value has changed with versions,

> at present I think you only get the endpoint_actual_value (or

> rather, the first 32 bytes thereof) if there are two entries in

> endpoint_value where the truncated value are the same even

> though the actual values are different.

>

>

> The entire set of scripts for the book, including the relevant function is

> in the ZIP file. The script is called char_value.sql in the subdirectory

> for

> chapter six

>

>     http://www.jlcomp.demon.co.uk/cbo_book/book_cbo_scripts.zip

>

> Because of the rounding to 15 s.f., you cannot reverse the stored

> endpoint_value back to the original text value - but you could

> probably get the first 5 characters.

>

>

> Because the

>

>

> Regards

>

> Jonathan Lewis

> http://www.oracle.com/technology/community/oracle_ace/ace1.html#lewis

>

> The Co-operative Oracle Users' FAQ

> http://www.jlcomp.demon.co.uk/faq/ind_faq.html

>

> Cost Based Oracle: Fundamentals

> http://www.jlcomp.demon.co.uk/cbo_book/ind_book.html

>

>

> ----- Original Message -----

> From: "Charles Schultz" <sacrophyte_at_gmail.com>

> To: <oracle-l_at_freelists.org>

> Sent: Friday, August 04, 2006 6:41 PM

> Subject: Re: endpoint_value and endpoint_actual_value

>

>

> >I would like to revisit this thread briefly. I believe Jerry was

> referring

> > back to Lex's response:

> > http://www.freelists.org/archives/oracle-l/09-2004/msg00243.html

> >

> > He also mentioned hexstr from AskTom:

> >

>

http://asktom.oracle.com/pls/ask/f?p=4950:8:5671668926260613952::NO::F4950_P
8_DISPLAYID,F4950_P8_CRITERIA:707586567563


> >

> > Woflgang speculated that Oracle only encodes the first 6 characters, and

> > will populate actual_value for character fields "when it needs to".

> >

> > Given all this, it seems that there is no way to reverse-engineer a

> bucket

> > on a character column consistently. Is that still true in 10gR2? In my

> own

> > testing, this seems to be the case, especially if the column is larger

> than

> > 6 characters. Even when it is not (when the column is less than 6

> > characters), the "encoding" process still makes decoding rather

> difficult. I

> > used the hexstr function but it is too easy to get control characters in

> the

> > stream (even using substr).

> >

> > Is there any other way to analyze the bucket information for histograms

> on

> > character fields?

> > Thanks,

> >

> > --

> > Charles Schultz

> >

>

> --

> http://www.freelists.org/webpage/oracle-l

>

>

>



-- 
Charles Schultz



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End of oracle-l Digest V3 #226
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