SQL$HELP_OLD72.HLB  —  ALTER  DATABASE  Arguments  FAST_COMMIT
    Syntax options:

    FAST COMMIT IS ENABLED | FAST COMMIT IS DISABLED

    By default, Oracle Rdb writes updated database pages to the
    disk each time a transaction executes the COMMIT statement. If
    a transaction fails before committing, Oracle Rdb only needs to
    roll back (undo) the current failed transaction; it never has to
    redo previous successful transactions.

    You can change the commit processing method by enabling journal
    fast commit processing. With journal fast commit enabled, Oracle
    Rdb keeps updated pages in the buffer pool (in memory) and does
    not write the pages to the disk when a transaction commits. The
    updated pages remain in the buffer pool until the process meets a
    condition specified by the database administrator or applications
    programmer. At the moment the condition is met (the checkpoint),
    all the pages the process updated for multiple transactions are
    written to the disk.

    You can set a checkpoint for your process when:

    o  A fixed number of transactions are committed or aborted. You
       set this by specifying CHECKPOINT EVERY n TRANSACTIONS.

    o  A specified time interval elapsed. You set this by specifying
       the CHECKPOINT TIMED EVERY n SECONDS clause.

    o  The after-image journal (.aij) file increased by a specified
       number of blocks. You set this by specifying the CHECKPOINT
       INTERVAL IS n BLOCKS clause.

    If a transaction fails, Oracle Rdb must undo the current, failed
    transaction and redo all the committed transactions since the
    last checkpoint. Redoing updates involves reading the .aij file
    and reapplying the changes to the relevant data pages.

    Fast commit processing applies only to data updates: erase,
    modify, and store operations. Transactions that include
    data definition statements, such as create logical area or
    create index operations, force a checkpoint at the end of the
    transaction. If you do not specify values with the FAST COMMIT
    clause, the default values are applied.

                                   NOTE

       To enable FAST COMMIT, you must first enable after-image
       journaling.
Close Help