Subject | RE: [Firebird-Java] Strange initial startup behavior |
---|---|
Author | Helen Borrie |
Post date | 2003-07-16T16:56:10Z |
At 05:31 PM 16/07/2003 +0100, you wrote:
it's the one that opens the database file. The db file gets opened once
and only once.
the longer it takes.
by the server. The DBCache gets "emptied" when the server shuts down and
releases its resources.
it on firebird-support or firebird-devel. You'll HAVE to believe Ann. She
was the midwife at the birth of this DBMS.
connections.
normal server won't shut down unless there are no connections (which will
eventually be the case if a forced shutdown is performed).
explore the possibility that the disk-thrashing at startup has nothing to
do with the server and everything to do with the OS environment.
Helen
>Hi,That's not encouraging.
>
>I've used .fdb extension since I began using XP and I see this behaviour
>with .fdb extension.
>I planned to investigate this at some point - but havent done so yet and soThe first db access is the one that triggers off the SystemRestore because
>also am unaware of
>exactly where it occurs - although it seems to be on first db access
it's the one that opens the database file. The db file gets opened once
and only once.
> and gets longer as the databaseThat because SystemRestore is a filesystem copy. So the bigger the file,
>grows - the hd light stays on continously - and it seems to fo for long
>enough to have loaded all the
>pages in the database.
the longer it takes.
>But this does not happen every time it starts - but I have not seen a:-)
>corelation between this and restarting
>windows but I havent been looking.
>Perhaps I am running a query which ends up needing to visit many pages inDatabase pages aren't "cached by the OS" - they are cached in the DBCache
>the db and these end up getting cached by
>OS
by the server. The DBCache gets "emptied" when the server shuts down and
releases its resources.
>so removing the cost of loading these on susequent start up - I will needYou could save yourself a lot of effort by simply asking Ann Harrison about
>to investigate this to really find out.
it on firebird-support or firebird-devel. You'll HAVE to believe Ann. She
was the midwife at the birth of this DBMS.
> >In normal client/server mode, it's the server that opens the file and getsAnd only one connection. The embedded server doesn't accommodate multiple
> >the exclusive lock, so it will be the first user to log on who experiences
> >the delay.
>
>The database is only accessed by the app and there is only one instance of
>the app.
connections.
>So when the app closes all the connections to the DBthere can only be one.
>(which I guessIt's not the same. The embedded server closes the ONLY connection. The
>should occur on the server because the process owning the socket is closed)
>I guess it should cause the server to close the file - so in that respect it
>should be the same.
normal server won't shut down unless there are no connections (which will
eventually be the case if a forced shutdown is performed).
>But when in client/server mode the server actually has a chance to close theEngage with Ann in a discussion of what the *server* does. And at least
>file - whereas in embedded mode the server process just disappears - which
>is what led to my previous hypothesis.
explore the possibility that the disk-thrashing at startup has nothing to
do with the server and everything to do with the OS environment.
>I cant be 100% sure that it only occurs with embedded server though. BasiclyAnyway, time for me to go to bed.
>I need to investigate this - I had just realised I had similar thing
>happening and that was what I though might be the cause.
Helen