Subject Re: [firebird-support] Re: Firebird Embedded open database file on network share
Author Ann Harrison
On Tue, Jan 20, 2015 at 8:35 AM, ralf.erdmann@... [firebird-support] <firebird-support@yahoogroups.com> wrote:


Never worked with Config-Options so far.
Are all options set in the firebird.conf file?

You really shouldn't access a firebird database on a network share.  I started to write "unless your absolutely sure no one else can access the database simultaneously."  I didn't because if there is a second connection the failure is catastrophic.   

When I started with firebird embedded I found many warnings that it can only handle one connection to a database. If I understood it right this was changed with version 2.5.x

The embedded mode can handle multiple connections but all of the connections must be from the same process.  Within that process, Firebird manages page changes to avoid having one connection overwrite changes made by another.  



Do you mean corruption will occur because firebird embedded can still handle only one connection at a time or is it because of the storage location of the file on a network share?


In a network share with multiple embedded engines accessing the same file, each engine assumes it has full control over the database and happily writes over changes made by other processes.  Thus you get pages that were allocated for data by one process turned into indexes pages in another table by another process.  Eventually something goes catastrophically wrong - typically a transaction inventory page turns into something else - and you lose all access to the data.

Good luck,

Ann