[Samba] How important are oplocks?

Jim Morris jim at morris-world.com
Thu Dec 19 14:24:01 GMT 2002

On Thu, 2002-12-19 at 03:56, Marian Mlcoch, Ing wrote:

> Thanks Jim for best report of oplock as i read.
> Super can be if you can add info or link about list of dangerous database
> engines for oplocks...
> Btw.  Foxpro 2.6 = is ok.
>           Foxpro 7.. = bad.
>           Clipper    =  dangerous...
> exist this list for off oplocks?

Thanks. But unfortunately, its not that simple.I doubt for example that
one version of FoxPro will be good with oplocks, while another is bad. 
The entire problem with oplocks and shared-file databases such as dBASE,
FoxPro, Paradox, Access, etc, is with file caching on the client side
(the OPLCOCK), and that client system not breaking the oplock when
requested.  Even when the breaks do happen properly, the time to write
the file back out to the server may be significant, causing a LOOOOONG
delay on the 2nd client to open the file.

When you see oplock problems, I guess you could say it is more client-OS
and hardware dependant than it is on the software involve. It just so
happens that the type of software that runs into oplock related issues
most often is shared-file database software. Most other applications do
not have 2 or more users opening the same file at the same time on a
routine basis.
| Jim Morris  |  Email: Jim at Morris-World.com
|             |    AIM: JFM2001

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