HELPLIB.HLB  —  RMU72  Analyze  Cardinality  Command Qualifiers

1  –  Confirm

    Confirm
    Noconfirm

    Specify the Confirm qualifier with the Update qualifier to
    gain more control over the update function. When you specify
    the Confirm qualifier, you are asked whether the update should
    be performed for each selected table or index whose stored
    cardinality value is different from its actual cardinality value.
    You can respond with YES, NO, QUIT, or an alternative value for
    the stored cardinality.

    Specifying YES means that you want to update the stored
    cardinality with the actual cardinality value. Specifying NO
    means that you do not want to update the stored cardinality
    value. Specifying QUIT aborts the RMU Analyze Cardinality
    command, rolls back any changes you made to stored cardinalities,
    and returns you to the operating system prompt. Specifying an
    alternative value updates the stored cardinality value with the
    alternative value.

    When you specify the Noconfirm qualifier, you are not given the
    option of updating stored cardinality values with an alternative
    value of your own choosing. Instead, the stored cardinality
    values that differ from the actual cardinality values are
    automatically updated with the actual cardinality values.

    The default is the Noconfirm qualifier.

    The Confirm and Noconfirm qualifiers are meaningless and are
    ignored if they are specified without the Update qualifier.

2  –  Output

    Output=file-name

    Specifies the name of the file where output will be sent. The
    default is SYS$OUTPUT. The default output file type is .lis, if
    you specify a file name.

3  –  Transaction Type

    Transaction_Type=option

    Allows you to specify the transaction mode for the transactions
    used to perform the analyze operation. Valid options are:

    o  Automatic

    o  Read_Only

    o  Noread_Only

    You must specify an option if you use this qualifier.

    If you do not specify any form of this qualifier, the
    Transaction_Type=Automatic qualifier is the default. This
    qualifier specifies that Oracle RMU is to determine the
    transaction mode used for the analyze operation. If any storage
    area in the database (including those not accessed for the
    analyze operation) has snapshots disabled, the transactions used
    for the analyze operation are set to read/write mode. Otherwise,
    the transactions are set to read-only mode.

    The Transaction_Type=Read_Only qualifier specifies the
    transactions used to perform the analyze operation be set to
    read-only mode. When you explicitly set the transaction type to
    read-only, snapshots need not be enabled for all storage areas
    in the database, but must be enabled for those storage areas that
    are analyzed. Otherwise, you receive an error and the analyze
    operation fails.

    You might select this option if not all storage areas have
    snapshots enabled and you are analyzing objects that are stored
    only in storage areas with snapshots enabled. In this case, using
    the Transaction_Type=Read_Only qualifier allows you to perform
    the analyze operation and impose minimal locking on other users
    of the database.

    The Transaction_Type=Noread_Only qualifier specifies that
    the transactions used to for the analyze operation be set to
    read/write mode. You might select this option if you want to
    eradicate the growth of snapshot files that occurs during a read-
    only transaction and are willing to incur the cost of increased
    locking that occurs during a read/write transaction.

4  –  Update

    Update
    Noupdate

    Specify the Update qualifier to update the stored cardinality
    values of tables and indexes. You can perform an update only when
    the stored cardinality values differ from the actual cardinality
    values. When updating cardinality values, Oracle Corporation
    recommends that you update the stored cardinality values with
    the actual cardinality values, not with an alternative value
    of your own choosing. Specifying a value other than the actual
    cardinality value can result in poor database performance. The
    default is the Noupdate qualifier.

    Using the Update qualifier allows you to update the stored
    cardinality values of the specified tables and indexes even when
    the RDB$SYSTEM storage area is designated for read-only access.
    If you have set the RDB$SYSTEM storage area to read-only access,
    Oracle RMU sets it to read/write during execution of the RMU
    Analyze Cardinality command with the Update qualifier. Oracle RMU
    resets the area to read-only when the operation completes.

    If you are updating the stored cardinality for a table or index,
    and a system failure occurs before the RDB$SYSTEM storage area is
    changed back to read-only access, use the SQL ALTER DATABASE
    statement to manually change the database back to read-only
    access.

    However, note that if you have set the area to read-only, the
    update operation specified with the Update qualifier commences
    only if the database is off line or the database is quiescent.

    If you specify a table name parameter with an RMU Analyze
    Cardinality command that includes the Update qualifier, the
    associated indexes are not updated; you must specify each table
    and index you want to be updated or accept the default (by not
    specifying any table or index names) and have all items updated.

    Oracle Corporation recommends that you use the Update qualifier
    during offline operations or during a period of low update
    activity. If you update a cardinality while it is changing
    (as a result of current database activity), the end result is
    unpredictable.

    Specify the Noupdate qualifier when you want to display the
    stored and actual cardinality values only for the specified
    tables and indexes.
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