snapshot in myoodb?

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Ruud.Van
2008-01-31
2013-04-10
  • Ruud.Van
    Ruud.Van
    2008-01-31

    Is there anyone can tell that The "snapshot" in myoodb is based on Copy-On-Write OR Mirror-Data-Set?

     
    • Thomas Hazel
      Thomas Hazel
      2008-02-02

      ibmzz,

      let me answer your question like this instead of comparing it to COW or Mirror-Data-Set.

      1) every database object method that has a "Write" annotation persists immediately and all clients will see the
         change. i call this an "implicit transactions", in other words, an internal transaction is created under the hood.

      2) "Write" methods that are called within a transaction scope [ tx = db.createTransaction(); tx.begin() ] are
         what i call an explicit transaction and the object in question is "snapshot-ed". Snaphots can either be
         committed [ tx.commit() ] or rolled back [ tx.rollback() ].

         it should be noted that subsequent [ tx.begin() ] will continue the snapshot-ing process. all will see these
         changes ( dirty reads ). myoodb can also be built to have clients access "blocked" until the pending changes
         have been committed; or with a few tweaks, it can be configured to have clients "not-block" and access only
         the committed changes and not the pending changes

      - tom