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-----Original Message-----
From: FreeLists Mailing List Manager [mailto:ecartis@xxxxxxxxxxxxx] 
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@xxxxxxxxx
Subject: ganesh-raja wants to share sites with you...

ganesh-raja (ganesh.raja@xxxxxxxxx) 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




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

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

dont spam the list with this please
On 06/08/06, ganesh.raja@xxxxxxxxx <ganesh.raja@xxxxxxxxx> wrote:
>
>
>



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

Date: Sun, 6 Aug 2006 07:58:58 -0500
From: "Charles Schultz" <sacrophyte@xxxxxxxxx>
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@xxxxxxxxxxxxxxxxxx> 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@xxxxxxxxx>
> To: <oracle-l@xxxxxxxxxxxxx>
> 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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