Re: Migrating to Oracle on Windows

On Mon, 21 May 2007 10:21:40 -0700, hasta_l3 wrote:

> " With one important exception, file views derived from a single file
> mapping object
> are coherent or identical at a specific time. If multiple processes have
> handles of
> the same file mapping object, they see a coherent view of the data when
> they
> map a view of the file." (http://msdn2.microsoft.com/en-us/library/
> aa366537.aspx)

What is a "coherent view"? Does it reflect any changes to the mapped area immediately? My information tells me that it is not the case. The "consistent view" means that all users will see anything written to the file immediately, which is useless.

>
> Recall that mapped files are backed up in virtual memory. You need to
> flush if
> you want to update the underlying file. But people using mapped files
> for shared

Unless you flush, other users will not see your changes. This is not mmap because Windows doesn't support shared memory.

> memory usually dont even have such a file (you can map directly the
> paging file)
>
> This said, I would really *love* to be shown wrong...
>

>> What is needed are standard IPC primitives, not supported by windows.

Standard IPC primitivies. Look into manual pages under IPC: shmat, shmget,shmop,shmctl, semget,semop and all the rest:

   | ATTRIBUTE TYPE | ATTRIBUTE VALUE |

    |_____________________________|_____________________________|
    | Availability                | SUNWipc (32-bit)            |
    |_____________________________|_____________________________|
    |                             | SUNWipcx (64-bit)           |
    |_____________________________|_____________________________|


SEE ALSO
     ipcrm(1),  savecore(1M),  msgget(2),  msgrcv(2),  msgsnd(2),
     semget(2),  semop(2), shmctl(2), shmget(2), shmop(2), attri-
     butes(5), environ( 5)

The manual page is ipcs on Solaris:

$ uname -a
SunOS lpo-oracle-01 5.8 Generic_117350-39 sun4u sparc SUNW,Ultra-80 $

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