Allows you to alter the database shared memory configuration
    without requiring that the database be open.

1  –  Description

    You can use the RMU Set Shared_Memory command to alter the
    database shared memory configuration without requiring that the
    database be open.

2  –  Format

  (B)0RMU/Set Shared_Memory root-file-spec

  Command Qualifiers              x Defaults
                                  x
  /[No]Log                        x Current DCL verify value
  /[No]Rad_Hint=n                 x None
  /Type={Process|Resident|System} x None

3  –  Parameters

3.1  –  root-file-spec

    Specifies the database root file for which you want to modify the
    shared memory configuration.

4  –  Command Qualifiers

4.1  –  Log

    Log
    Nolog

    Specifies whether the processing of the command is reported to
    SYS$OUTPUT. Specify the Log qualifier to request log output and
    the Nolog qualifier to prevent it. If you specify neither, the
    default is the current setting of the DCL verify switch.

4.2  –  Rad Hint

    Rad_Hint=n
    Norad_Hint

    Indicates a request that memory should be allocated from the
    specified OpenVMS Alpha Resource Affinity Domain (RAD). This
    qualifier specifies a hint to Oracle Rdb and OpenVMS about where
    memory should be physically allocated. It is possible that if
    the requested memory is not available, it will be allocated from
    other RADs in the system. For systems that do not support RADs, a
    Rad_Hint value of zero is valid.

    The Rad_Hint qualifier is only valid when the shared memory type
    is set to Resident. If you set the shared memory type to System
    or Process, you disable any previously defined RAD hint.

    Use the Norad_Hint qualifier to disable the RAD hint.

                                   NOTE

       OpenVMS support for RADs is available only on the
       AlphaServer GS series systems. For more information about
       using RADs, refer to the OpenVMS Alpha Partitioning and
       Galaxy Guide.

4.3  –  Type

    Type=option

    If you use the Type qualifier, you must specify one of the
    following options:

    o  Process

       Specifies traditional shared memory global section, which
       means that the database global section is located in process
       (P0) address space and may be paged from the process working
       set as needed.

    o  Resident

       Specifies that the database global section is memory resident
       in process (P0) address space using OpenVMS Alpha shared page
       tables. This means that the global section is fully resident,
       or pinned, in memory, and uses less physical and virtual
       memory (for process page tables) than a traditional shared
       memory global section.

    o  System

       Specifies that the database global section is located in
       OpenVMS Alpha system space, which means that the section is
       fully resident, or pinned, in memory, does not use process
       (P0) address space, and does not affect the quotas of the
       working set of a process.

5  –  Usage Notes

    o  This command requires exclusive database access (the database
       cannot be open or accessed by other users).

    o  Only one value can be supplied to the Rad_Hint qualifier. The
       indicated RAD must contain memory.

    o  When shared memory is set to System (with Galaxy enabled) or
       to Resident, then the process that opens the database must be
       granted the VMS$MEM_RESIDENT_USER identifier.

    o  For applications that can be partitioned into one or more
       RADs, the Rad_Hint qualifier allows additional control
       over exactly where memory for caches and global sections
       is allocated. This control can permit increased performance
       if all application processes run in the same RAD, and the
       database and row cache global sections also reside in that
       same RAD.

    o  When Resident shared memory is specified, the global demand-
       zero pages are always resident in memory and are not backed
       up by any file on any disk. The pages are not placed into the
       process's working set list when the process maps to the global
       section and the virtual memory is referenced by the process.
       The pages are also not charged against the process's working
       set quota or against any page-file quota.

    o  To save physical memory, Oracle Rdb generally attempts to
       create and use shared page tables when creating large resident
       global sections.

6  –  Examples

    Example 1

    The following example sets the memory type to Resident and
    requests that it be put in RAD 4.

    $ RMU/SET SHARED_MEMORY/TYPE=RESIDENT/RAD_HINT=4

    Example 2

    This example specifies that system space buffers are to be used.

    $ RMU/SET SHARED_MEMORY/TYPE=SYSTEM

    Example 3

    The following example specifies that process address space shared
    memory is to be used.

    $ RMU/SET SHARED_MEMORY/TYPE=PROCESS/LOG