RE: Mabye OT: Was Re: Different clocks for different instances.

From: Robertson Lee - lerobe <lerobe_at_acxiom.co.uk>
Date: Wed, 19 Dec 2001 09:35:09 -0800
Message-ID: <F001.003E049C.20011219090909@fatcity.com>

Well I
say,
<SPAN

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that
is also the case on Tru64 as well.
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How
pedantic is UNIX ??
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<FONT face=Tahoma
size=2>-----Original Message-----From: Brian McGraw [mailto:Brian.McGraw_at_infinity-insurance.com]Sent: 19 December 2001 16:16To: Multiple recipients of list ORACLE-LSubject: Mabye OT: Was Re: Different clocks for different instances.Speaking of the system clock, here's something interesting that I stumbled across a few years back... Background: For those of you who may not know, the Julian calendar was abandoned by England, in favor of the Gregorian calendar, in 1752 because of date discrepancies. To facilitate this, September 3 - 13 were eliminated. This is actually reflected in UNIX (well, Solaris anyway) by issuing the 'cal 1752' command and looking at the month of September:

          
  Jul                    
  Aug

Sep S M Tu W Th F

  S    S  M Tu  W Th  F  S    
  S  M Tu  W Th  F  S 
            1  2  
  3  
  4                      
  1          1  2 14 15

16 5 6 7 8 9 10

  11    2  3  4  5  6  7  
  8   17 18 19 20 21 22 23 12 13 14 15 16 17 
  18    9 10 11 12 13 14 15   24 25 26 27 28 29 30

19 20 21 22 23 24 25 16 17 18 19 20 21 22 26 27 28 29 30 31 23 24 25 26 27 28 29 More info. on why the switch over occurred is available at <A href="http://www.bicknell.net/books/pc1981/p_calender.htm">http://www.bicknell.net/books/pc1981/p_calender.htm, for those of you with morbid curiosity. Anyway - I was doing some Y2K testing a few years back, and playing with NLS_DATE_FORMAT queries when I learned this little tidbit. I decided to test the Oracle date formats because - hey - they'll be okay because they're based on Unix, right?

  Wrong:  Issue the following query: 
  select     sysdate

  ,add_months(sysdate,-2988)

  ,add_months(sysdate,-2988) - 10 from dual;   And see the following results:
  SYSDATE

  ADD_MONTHS(SYSDATE,- ADD_MONTHS(SYSDATE,- -------------------- 
  -------------------- -------------------- 19-DEC-2001 10:07:02

  19-DEC-1752 10:07:02 09-DEC-1752 10:07:02   The third column represents a date which, technically, does not   exist. : )
  Brian
  Kimberly Smith wrote:
  Oracle uses the system clock. So I would have     to say no.
    -----Original Message----- Pollard Sent: Tuesday, December 18,     2001 6:50 PM To: Multiple recipients of list ORACLE-L     Gooday Oraclers, is it possible to have different instances, on the     same dB server, operating with different clocks - ie different     date/times?
    Environment: Compaq-Digital Tru64 Unix, Oracle 8.0.6, DS20     ---

    Kevin Pollard | PODBA (Pretend Oracle DBA) <A     href="mailto:kpollard_at_scu.edu.au">mailto:kpollard_at_scu.edu.au     | Administrative Systems Unit     Phone:+61 (02)     6620 3969 | Southern Cross University           FAX:+61 (02) 6626 9122 | P.O.     Box 157

    Room: R1-40a | Lismore NSW 2480, Australia               <A
    href="http://staff.scu.edu.au/asu/index.html">http://staff.scu.edu.au/asu/index.html

Please see the official ORACLE-L FAQ: <A href="http://www.orafaq.com">http://www.orafaq.com -- Author: Kevin Pollard INET: kpollard_at_scu.edu.au Fat City Network Services    -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California        -- Public Internet access / Mailing Lists
To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: <A href="http://www.orafaq.com">http://www.orafaq.com -- Author: Kimberly Smith INET: ksmith2_at_myfirstlink.net Fat City Network Services    -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California        -- Public Internet access / Mailing Lists
To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).-- -------------------------------------- | Brian McGraw     --     Oracle DBA | | Central Alabama Oracle Users Group | |------------------------------------| | <A href="mailto:BMcGraw_at_mindspring.com">mailto:BMcGraw_at_mindspring.com      | | <A href="http://bmcgraw.home.mindspring.com">http://bmcgraw.home.mindspring.com | --------------------------------------

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