System change number

Oracle documentation describes this as

"A stamp that defines a version committed a database to a point in time. Oracle assigns each transaction posted a single SNA. »
or
"When a user commits a transaction, the transaction is assigned a system change number (SCN), which records the Oracle as well as redo the transaction in the redo log entries"

etc.

I'm a bit confused with the definition of the SNA in Oracle and documentation I see personally. I have a test database, locally, which I'm connected to.

When I have a query as follows the V$ DATABASE, it returns the values as

SELECT current_scn IN the database of v$.
1973076

query again after a few seconds and

SELECT current_scn IN the database of v$.
1973095


I'm assuming that the number changes each time a transaction are committed. However, I realize now, the opposite is true... after seeing the above, that I realize that whenever a transaction occurs, it is assigned a SNA, but the change in the value of the CNS is not in the transaction are committed, I guess that it continues to automatically change all seconds. But sometimes it skips several numbers a second too. So I don't know what this change in value is based on?

Can someone explain which depends on the change in value SNA? All links to the Oracle documentation will be also gratefully appreciated!

Concerning

S diallo

sandeshd wrote:
Is continuous commits that cause the RCS to change, or the RCS changes permanently (regardless of the unit of time) and commited attributed to movements can get this YVERT value?

SNA does not increment by itself. This isn't like the constant opportunity tick of a clock. Instead, many functions within the Oracle request "the next SNA.

Every commit request a new SNA. There are also many other changes within the database that also require a new SNA. Each successive application will get the next YVERT derived in a simple increment.

Since the events that require SNA do not occur at regular intervals, you can consider the RCS to the tick of a clock that has an uneven interval between graduations.

However if having a real clock (wall) that records fast enough times (microseconds or even picoseconds, if the processor is fast enough), you can see each YVERT corresponds to a specific time on this real clock. For ordinary clocks without a PS-hand, you might see 5 SNA in a "seconds" SNA and 200 in the next 'second '.

BUT

SNA can be used as a clock.

Perhaps you've seen the clock sometimes recorded on a film. You will enter in the film you see the increase of the clock and you can see events as part of the film linked at this moment. In the same way, you will enter the SNA in the database, you can see changes to database (or 'events') at every moment.

Therefore, to re-create the database at any moment, you reset the database to any YVERT before that moment (perhaps through a backup) and apply you all database changes, YVERT by RCS (perhaps from your journals of recovery) up to the moment where you want to.

Tags: Database

Similar Questions

  • Come partita IVA of the di of the change number he associato al nostro account?

    Come partita IVA of the di of the change number he associato al nostro account?

    To the link below, click on the still need help? option in the blue box below and choose the option to chat or by phone...
    Make sure that you are logged on the Adobe site, having cookies enabled, clearing your cookie cache.  If it fails to connect, try to use another browser.

    Creative cloud support (all creative cloud customer service problems)
    http://helpx.Adobe.com/x-productkb/global/service-CCM.html ( http://adobe.ly/19llvMN )

  • HP 15 R203TX: CARD SYSTEM CHANGED BUT WHERE TO ENTER CT NUMBER TO REGISTER

    Recently, I changed my motherboard, at startup it says the serial number, product number are missing.

    To sort this, it is essential to have the number of CT of the new motherboard. I have the number but again CT

    the question is where should I enter my new CT number to enroll? Please help me.

    This can be done at a center of Service HP or an HP authorized service center.

    Data entry requires a DMI exclusive HP utility.

  • Cannot change 'number of results' Google search preferences; It remains fixed at 10, why?

    3.6 running on Windows 7. I deleted all cookies, delete preferences.js and don't know what else to do. This was the status for about a week now. The only thing I can think that I have installed at the same time is Microsoft Security Essentials, but its real time protection disabling did not alter behavior. It may be a question of system, since I have the same problem with Chrome and IE 8! I use ZoneAlarm, Symantec Endpoint Protection 11 or Spybot as well, but I don't know how those that would affect this particular configuration. Thanks in advance.

    Which is caused by a recent change on the Google site and the addition of instant search.

    If Instant Search is enabled in the settings of Google search page (link at the top right) then you get only 10 results.

    You must disable Instant Search and reload the result page, and then set the number of results to your preferred choice.

    It may not work if you change both at the same time.

  • Update of the T61 system changes the Type of product and the product ID

    Hello

    My T61 laptop has the following numbers

    Type XXXXXX 6464-CTO 08/87

    Product ID: 6464-V52

    I'm trying to update system but the system update watch instead of 6464-CTO product ID V52 is a mistake?

    Now I want to update BIOS, I can't change the V52 CTO I should?

    Moderator Note: serial number removed to avoid misuse.

    01805-253558 GERMANY

    your machine is covered in Germany, in order to use the local warranty service. Simply contact the number above.

  • HP 248 G1: How to change number of seri on bios

    My laptop is hp G1.i 248 again bios file copy Rom 25Q128Bvs.but when you're done, it comes very slow and the loss of information on the number of seri, produce key...

    I try to change the number of seri, but it can't boot from usb boot with single boot of the dowry boot.it usb boot win 8.

    How can I do?

    Please tell me.thanks you all!

    Hi @black0hackers,.

    To get your question more exposure I suggest you post in the trade forums since it is a commercial product. You can do it at Business Forum.

    You can reset the BIOS with this document by selecting the reload the default BIOS settings.

    Thank you.

  • Change number of four digits in the tables to a single number four?

    Using LabVIEW 2010, is it possible to change a whole four-digit (DBL, SGL, whatever) in an array of integers to a figure four, of the same type? Wasn't sure if there was a way to extract a number of thousands place, hundreds place, etc...

    -Ian

    Rest of quotient (math modulo) in a loop for using 10 as the denominator autoindex the rest out of the loop, loop 4 x.  There are many quick ways to do this.

  • Operating system changed from Windows 7 to Windows XP Home Edition. You will need to download Audio Driver & video Controller.

    I changed the OS on my laptop Toshiba from Windows 7 to Windows XP Home Edition. Everything seems to work fine, except that there is no sound. Checked PC Device Manager and noticed that I need to download & install a high definition Buss Audio Audio driver and a video controller (VGA Compatible).

    You need visit Toshiba support and download the drivers that you need for Windows XP for your laptop model specific. It is the responsibility of the manufacturer of the system (or manufacturer) to write drivers for their products for different operating systems - not Microsoft.

    Toshiba technical support
    http://www.CSD.Toshiba.com/cgi-bin/TAIS/support/JSP/home.jsp?NAV=product%20Support

    In addition, if your PC Toshiba laptop comes with Windows 7 so it's a fairly new machine, if this model was never sold with Windows XP may not be drivers for Windows XP.

    I hope this helps.

  • Cannot remove a folder. Error: Required the approval of the system changes to the folder and the files

    I recently encountered a problem with a file of unknown origin and content. When I try to delete files / folder I get a message that I need permission from the system to change the files or folders. I am the only user on my laptop and have always had administrator rights to make the changes necessary and desired.

    Hello

    1 are there any changes or updates made on the computer?

    2. What is the full and exact error message?

    Method 1:

    I suggest you run Microsoft Safety Scanner for any malware or spyware infection and check if it helps.

    http://www.Microsoft.com/security/scanner/en-us/default.aspx

    Note: the data files that are infected must be cleaned only by removing the file completely, which means there is a risk of data loss.

    Method 2:

    See article for appropriating the file and then delete it.

    Troubleshoot "access denied" when opening files or folders

    http://Windows.Microsoft.com/en-us/Windows-Vista/troubleshoot-access-denied-when-opening-files-or-folders

    See also:

    Why cannot delete a file or folder

    Let us know if it helps.

  • Restoration of the SYSTEM, change of password

    I use a Compaq 510 laptop with OS windows 7 starter.

    25 days ago, that I used the system restore option to fix my problem. She flashed up on the system, and then restore it asked for a password to enter. I entered my password and it says the username or the password is incorrect. I use the laptop for the past three months and changed the password three times. I tried my previous passwords also but no use.

    Please help me as I have imp data on the laptop.

    Try to log in as an administrator (or a different Admninstrator) and solve the problem of password on your account by assigning a new.

    If it is the only administrator account, and you can log in or change the passward to restore administrator privileges, then I am afraid that we cannot help you because we are forbidden to Microsoft Policy to help people who have lost or forgotten password:http://support.microsoft.com/kb/189126.

    I'm sorry, we can't be more helpful.

    Good luck!

    Lorien - MCSA/MCSE/network + / has + - if this post solves your problem, please click the 'Mark as answer' or 'Useful' button at the top of this message. Marking a post as answer, or relatively useful, you help others find the answer more quickly.

  • Change number of chassis version 2.0(3a)

    I looked everywhere online & all that I can find relating to change the chassis number is this article:

    http://ucschalkboard.blogspot.com/2011/08/re-number-UCS-chassis.html

    My question: is there a way to renumber the chassis WITHOUT downgrading any desired chassis be renumbered first? I can't lower the chassis at this stage. Any help or advice would be appreciated.

    ~ Tara

    Hello Tara,.

    Renumbering of the chassis is always disruptive change and can be done when we re-order.

    http://www.Cisco.com/en/us/docs/unified_computing/UCS/SW/GUI/config/Guide/2.0/b_UCSM_GUI_Configuration_Guide_2_0_chapter_0100010.html#task_7CE3D4DF1CEF42A2A7BE144FEDF8DAB5

    Is it possible to share on how the existing chassis number affects yoru deployment?

    HTH

    Padma

  • BlackBerry Smartphones operating system Version number

    Trying to run my 8350i energy management application, but need to know the version number of the operating system.

    Have it's info. Located?

    The program only supports version 6.0 or higher.

    Thanks in advance!


  • BlackBerry Smartphones change number of rings

    I have a Torch 9800 and I try to change the number of rings for an incoming call before it goes to voicemail?  I followed the instructions in the documentation, but when I go to the phone application, then to options, it says I should have a 'General Configuration' option and I did not.  Can't find anywhere!  Help!

    Boomer56 wrote:

    Torch is not a 'General Options' setting in the phone options.

    You are right! (Makes OS5).

    This user on the torch need to go to Options > sounds & ringtones > ringtone, but there is still no adjustment it takes time to voicemail. The user just needs to call their support of carrier.

  • XI Acrobat pro, crash the system, serial number now reinstalled revoked, cannot come into contact with adobe

    Hi, we recently had a system with a failed hard drive crash. have reinstalled most programs with success the new drive hard, but acrobat pro is coming the serial number removed and directs me to support. However, I'll just round in circles trying to get it resolved. can someone point me in the right direction of WHO to contact or e-mail me up and running? Thank you!

    serial numbers are not revoked (AFAIK) unless piracy is suspected.

    is revoked the exact word used in your error message?

  • Change number of positive to negative

    Hello

    I use the SUM function in a calculated field to add and subtract values and display the results in a 'Total'.  Subtraction requires the user to enter a negative number in the field of "losses".  I would like to create a user just enter a number and to have the field automatically change to a negative number.  Is there a way to do it, or should I move it in a different way?

    Capture.JPG

    A negative number in a column where the color (sign) is negative would indicate a positive number.

    I would make the calculation by using the subtraction operator. This can be done in the simplified or custom JavaScript options.

Maybe you are looking for