Question

I’m facing timeout issues when performing multiple SELECTs after moving database to a different server, in a relic (VB6 application) I’ve been tasked to patch up. Things worked flawlessly in the old environemnt, the new one contains carbon copies of the old tables.

NOTE! The new database was built from scratch (that is, DBA ran many CREATE TABLE + INSERT scripts to create carbon copies of tables then fill them with the old data).

This is the error source:

// "conn" is being initialized outside the function
Public Function PerformOperation(ByRef conn as ADODB.Connection, query as string) as Boolean
  Dim rs as ADODB.Recordset
  //This below is the timeout source
  rs.Open conn, query, adOpenStatic, adLockReadOnly

  If Not (rs.EOF or rs.BOF) Then
    rs.MoveFirst
    //assign data to many variables
  End If

ExitPoint:
  If Not (rs Is Nothing) Then
    If (rs.State = adStateOpen) Then rs.Close
    Set rs = Nothing
  End If   

  Exit Function

Error:
  MsgBox "Blah blah"
  Resume ExitPoint
  Resume 0

End Function

Function is called like this

conn = New ADODB.Connection
conn.ConnectionString = "..."
conn.Open

For i = 1 To RowCount //reading data from a grid component (data is correct!)
  //very long select here... kept short
  query = "SELECT something FROM somewhere WHERE <manyFields> = <manyValues>" 
  If PerformOperation(conn, query) = True Then
    //UPDATE another table based on the SELECT data
    // NOTE: this occurs on a DIFFERENT, INDEPENDENT ADODB.Connection object
  End If
Next i

The first time PerformOperation is called it goes through fine, second time through it times out no matter how long i set the CommandTimeout. It also works OK if the cycle “cycles” a single time.

Big problem here is, all I have to try things out is the production environment so I’ll need to be extra careful. I also don’t have a very deep DBA knowledge at hand… Just a very very old piece of software which will eventually be ported to .NET but needs to be dealt with in the meantime…

How can I check and/or fix this issue ? This has to work for any length of the For cycle

Many thanks for any suggestion (as always, if i missed any essential detail point it out and i’ll provide it if i can).

EDIT #1
I’ve expanded the first and secondo code blocks to provide deeper details about what’s going on. Comments changed in order to try and fix highlighting (single quotes mess up coloring).

EDIT #2
Enabling Multiple Active Result Sets (MARS) in the connection string didn’t help either.

Answer 1

Issue was solved editing this line:

If PerformOperation(conn, query) = True Then

like this

If PerformOperation(connOther, query) = True Then

Basically, method call has been moved to its own connection, declared exactly like the other one. Now it works, though I don’t really know why: this is the result of some wild editing in an attempt to patch things up.