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Enqueue Workprocess and database locking

As we all know that Oracle have its own locking mechanism, then Why we need Enqueue Work process which is also for locking?

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  • author's profile photo Former Member
    Former Member
    Posted on Jun 11, 2008 at 12:03 PM

    Hi.

    From the database point of view, every dialog step forms a physical and logical unit: the database transaction. The database lock administration can only coordinate this type of database transaction. From an SAP point of view, however,this is not sufficient, because SAP transactions, which are formed from a sequence of logically related work steps that are consistent in business terms, are generally made up of several dialog steps. SAP systems need to have their own lock management. This is implemented using the enqueue work process.

    regards,

    kaushal

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    • Former Member Former Member

      Hi,

      Why SAP needs Enqueue Workprocess for locking..
      

      Business objects must not be changed simultaneously by different users if consistency is to be maintained.

      in other word To ensure data consistency within an SAP system, you must ensure that data records cannot be accessed and changed by more than one user at any one time.

      to maintain data consistency Enqueue is required.

      The enqueue work process, also known as the lock work process, It allows multiple application servers to synchronize their access to the database and maintain the data consistency. In order for the system to run in a consistent manner, it must ensure that when a transaction's dialog steps are handled by different work processes, they retain the assigned locks until the end of the transaction or the intentional release of the lock.

      The function of this work process is to protect applications from blocking among themselves during data

      access. For that reason, a locking/unlocking mechanism must be present. This is the function of the enqueue.

      further more you can look at help.sap.com

      http://help.sap.com/saphelp_nw70/helpdata/EN/7b/f9813712f7434be10000009b38f8cf/frameset.htm

      regards,

      kaushal

  • author's profile photo Former Member
    Former Member
    Posted on Jun 11, 2008 at 01:39 PM

    In SAP with oracle envroinment, in Oracle point of view there is only one user OPS$. Whenever the the SAP is contacting the database it use to access though OPS$. SAP users are not directly contacting the DB. So Oracle can't maintain the locks for the SAP users. So SAP need the seperate locking system.

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    • > In SAP with oracle envroinment, in Oracle point of view there is only one user OPS$. Whenever the the SAP is contacting the database it use to access though OPS$.

      Sorry - but this is plain wrong.

      The OPS$ ist not used to access the business data. It cannot even see this data.

      Its only purpose is to get access to the password of the SAP<sid> user so that the workprocesses can logon as SAP<sid> (that's where the data really is stored) without 'knowing' the password beforehand.

      This is just a security mechanism specific for SAP on Oracle.

      KR Lars

  • author's profile photo Former Member
    Former Member
    Posted on Jun 12, 2008 at 07:40 AM

    Thaks so much Mr. Kaushal for your prompt reply..

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  • author's profile photo Former Member
    Former Member
    Posted on Jul 24, 2008 at 03:26 PM

    Okies

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