At 10:14 PM 07-08-01 -0400, Doug Chamberlain wrote:

> >IB isn't a file-based database.
>
>I respectfully think Helen is wrong here. The Interbase server (if it is
>SuperServer) can, indeed, open the GDB file in exclusive mode. All
>connections from clients will share that one open file access via the
>layered architecture within the server process. The only reason I can
>remember that it doesn't do this is that certain Interbase utilities (gfix,
>gstat, gsec?) also read the GDB file DIRECTLY. If the server had exclusive
>access then these utilities would not be able to read the GDB file at the
>same time.
>
>If the server is Classic rather than SuperServer architecture then each
>process needs to read and write to the GDB file independently (using a lock
>manager to coordinate). Therefore, in this situation what you describe is
>infeasible.
>
>However, I think all recent versions of Interbase for Win32 are SuperServer
>so this is irrelevant. The separate utility program access is not.

I think Doug is pretty close to right about this. I recollect one recent thread of discussion in firebird-devel (or ib-architect possibly) where giving the Windows server exclusive access to the database file was proposed as a fix to the problem for superserver. AFAIK, it didn't resolve to a correction strategy.

I'll leave Sean to update you on this since it looks as if he is undertaking to do something about it for FB 1.

regards
Helen

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