Memory leaks?

[T Clancey]

Hi, I have an app which connects to an Access database on a server, there
are around 10 clients. It's a fairly heavy data intensive app, but most of
the traffic is look up data.

While the system appears to run completely error free around every 6 weeks
the server stops serving the network share where the database resides. When
a client tried to connect you get an error message something like Not enough
resources or disk failure. Resetting the server cleares the problem. More
worrying is a large database corruption that happened just a couple of days
ago.

As far as I can tell my code is correct and I'm not leaving anything open or
connected that shouldn't be. Is there any way to trace or track what
connections and/or resources are being used by each Client? Or if my code
is generating any memory leaks?

Cheers,
Tull.

[teslar91]

Check to see if your Access db is being opened repeatedly and never
closed, or if a large number of file locks are accumulating on it. For
a Windows server, you can check here:

Control Panel/Administrative Tools/Computer Management/Shared
Folders/Open Files

[Steve Long]

This can be a problem with Access Databases and can even cause corruption
(IMO, base on anecdotal experience). I would back this database up daily so
that you don't loose too much data, in case corruption does occur.
Additionally, I would compact this database often if you are doing any kind
of data manipulation at all. You can do this programmatically via the JRO
library.

Dim src As String

Dim dest As String

Dim tmpDB As String

Dim je As JRO.JetEngine = New JetEngineClass

tmpDB = CLog.GetAppPath() & "\tmp.mdb"

src = con.ConnectionString ' ADODB connection that has already been
opened

dest = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & tmpDB & ";Jet
OLEDB:Engine Type=5"

If con.State <ADODB.ObjectStateEnum.adStateClosed Then

con.Close()

End If

je.CompactDatabase(src, dest)

Kill(m_sDBName) ' m_sDBName is the name of the database and it's location

File.Move(tmpDB, m_sDBName)

con.Open()

je = Nothing

Hope you were looking for something like this. Otherwise, sorry I posted
nonsense for you.

Steve

"T Clancey" <tu**@idcodeware.co.ukwrote in message
news:Ko********************@bt.com...

Hi, I have an app which connects to an Access database on a server, there
are around 10 clients. It's a fairly heavy data intensive app, but most
of the traffic is look up data.

While the system appears to run completely error free around every 6 weeks
the server stops serving the network share where the database resides.
When a client tried to connect you get an error message something like Not
enough resources or disk failure. Resetting the server cleares the
problem. More worrying is a large database corruption that happened just
a couple of days ago.

As far as I can tell my code is correct and I'm not leaving anything open
or connected that shouldn't be. Is there any way to trace or track what
connections and/or resources are being used by each Client? Or if my code
is generating any memory leaks?

Cheers,
Tull.

[Scott M.]

I think you've got a lot of unneccessary code here. All you need is this:

dim dbPath As String = (path to database here)
dim conString As String = "Provider=Microsoft.JET.OLEDB.4.0;Data Source=" &
dbPath

dim con As New OleDB.OleDBConnection(conString)

Try
con.Open

...your database code here...

Catch ex As OleDbException
...handle database exceptions here...
Catch ex As Exception
...handle CLR exceptions here
Finally
con.close
con.dispose
End Try

Notes:

In ADO.NET, you can call the .Close() method of any object that has one
without worrying about whether it is actually open or not. If it is open,
it will close it. If it is already closed, no action is taken & no
exception is thrown.

You should always open your connection inside of a Try...Catch and you
should always close it and dispose of it in the Try...Catch's Finally so it
will always get closed and disposed, even if there are exceptions thrown
along the way.
"Steve Long" <St**********@NoSpam.comwrote in message
news:O4**************@TK2MSFTNGP03.phx.gbl...

This can be a problem with Access Databases and can even cause corruption
(IMO, base on anecdotal experience). I would back this database up daily
so that you don't loose too much data, in case corruption does occur.
Additionally, I would compact this database often if you are doing any
kind of data manipulation at all. You can do this programmatically via the
JRO library.

Dim src As String

Dim dest As String

Dim tmpDB As String

Dim je As JRO.JetEngine = New JetEngineClass

tmpDB = CLog.GetAppPath() & "\tmp.mdb"

src = con.ConnectionString ' ADODB connection that has already been
opened

dest = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & tmpDB & ";Jet
OLEDB:Engine Type=5"

If con.State <ADODB.ObjectStateEnum.adStateClosed Then

con.Close()

End If

je.CompactDatabase(src, dest)

Kill(m_sDBName) ' m_sDBName is the name of the database and it's
location

File.Move(tmpDB, m_sDBName)

con.Open()

je = Nothing

Hope you were looking for something like this. Otherwise, sorry I posted
nonsense for you.

Steve

"T Clancey" <tu**@idcodeware.co.ukwrote in message
news:Ko********************@bt.com...

>Hi, I have an app which connects to an Access database on a server, there
are around 10 clients. It's a fairly heavy data intensive app, but most
of the traffic is look up data.

While the system appears to run completely error free around every 6
weeks the server stops serving the network share where the database
resides. When a client tried to connect you get an error message
something like Not enough resources or disk failure. Resetting the
server cleares the problem. More worrying is a large database corruption
that happened just a couple of days ago.

As far as I can tell my code is correct and I'm not leaving anything open
or connected that shouldn't be. Is there any way to trace or track what
connections and/or resources are being used by each Client? Or if my
code is generating any memory leaks?

Cheers,
Tull.

[Steve Long]

Hmmm, didn't know that. Thanks Scott. I guess I was just a little scardy
cat... :)

S

"Scott M." <s-***@nospam.nospamwrote in message
news:%2****************@TK2MSFTNGP04.phx.gbl...

>I think you've got a lot of unneccessary code here. All you need is this:

dim dbPath As String = (path to database here)
dim conString As String = "Provider=Microsoft.JET.OLEDB.4.0;Data Source="
& dbPath

dim con As New OleDB.OleDBConnection(conString)

Try
con.Open

...your database code here...

Catch ex As OleDbException
...handle database exceptions here...
Catch ex As Exception
...handle CLR exceptions here
Finally
con.close
con.dispose
End Try

Notes:

In ADO.NET, you can call the .Close() method of any object that has one
without worrying about whether it is actually open or not. If it is open,
it will close it. If it is already closed, no action is taken & no
exception is thrown.

You should always open your connection inside of a Try...Catch and you
should always close it and dispose of it in the Try...Catch's Finally so
it will always get closed and disposed, even if there are exceptions
thrown along the way.
"Steve Long" <St**********@NoSpam.comwrote in message
news:O4**************@TK2MSFTNGP03.phx.gbl...

>This can be a problem with Access Databases and can even cause corruption
(IMO, base on anecdotal experience). I would back this database up daily
so that you don't loose too much data, in case corruption does occur.
Additionally, I would compact this database often if you are doing any
kind of data manipulation at all. You can do this programmatically via
the JRO library.

Dim src As String

Dim dest As String

Dim tmpDB As String

Dim je As JRO.JetEngine = New JetEngineClass

tmpDB = CLog.GetAppPath() & "\tmp.mdb"

src = con.ConnectionString ' ADODB connection that has already
been opened

dest = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & tmpDB & ";Jet
OLEDB:Engine Type=5"

If con.State <ADODB.ObjectStateEnum.adStateClosed Then

con.Close()

End If

je.CompactDatabase(src, dest)

Kill(m_sDBName) ' m_sDBName is the name of the database and it's
location

File.Move(tmpDB, m_sDBName)

con.Open()

je = Nothing

Hope you were looking for something like this. Otherwise, sorry I posted
nonsense for you.

Steve

"T Clancey" <tu**@idcodeware.co.ukwrote in message
news:Ko********************@bt.com...

>>Hi, I have an app which connects to an Access database on a server,
there are around 10 clients. It's a fairly heavy data intensive app,
but most of the traffic is look up data.

While the system appears to run completely error free around every 6
weeks the server stops serving the network share where the database
resides. When a client tried to connect you get an error message
something like Not enough resources or disk failure. Resetting the
server cleares the problem. More worrying is a large database
corruption that happened just a couple of days ago.

As far as I can tell my code is correct and I'm not leaving anything
open or connected that shouldn't be. Is there any way to trace or track
what connections and/or resources are being used by each Client? Or if
my code is generating any memory leaks?

Cheers,
Tull.