RC6: Memory-Cn visibility problem

Hello!

I would like to ask if it matters if the cConnection is created in the main process or if I can have a function in an activex dll that looks like this:

Code:

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Public Function NewMemDB(ByVal uName As String, ByVal uEncKey As String, uOutConnection As cConnection, uError As String) As Boolean

   
Dim iLine&
iLine = 1
go_start:
On Error GoTo ErrHandler


    Dim sb As IStringBuilder
    Set sb = NewStringBuilder

   
    sb.Append "file:" & uName      ' ->  file:drivescanner
    sb.Append "?"                  '? is query-indicator 
    sb.Append "mode=memory"        '  ->  file:drivescanner?mode=memory
    sb.Append "&"                  '& ist parameter-trenner ->  file:drivescanner?mode=memory&
    sb.Append "cache=shared"      '  ->  file:drivescanner?mode=memory&cache=shared

    Dim s$
    s = sb.ToString

    Set uOutConnection = New_c.Connection(s, DBCreateInMemory)
   
    uOutConnection.CreateNewDB s, uEncKey

    uOutConnection.ExecCmd "PRAGMA read_uncommitted=1"  'allow the Client, to "see" even the uncommitted inserts, the thread will perform
    uOutConnection.Execute "PRAGMA journal_mode=off"  'these settings will increase the Insert-Performance a bit
    uOutConnection.Synchronous = False

    NewMemDB = True
   
Exit Function
ErrHandler:
uError = "Error " & Err.Number & " (" & Err.Description & ") in procedure " & Quote("NewMemDB") & " of " & Quote("modobjects.bas") & ", Line: " & iLine
On Error GoTo -1
Debug.Assert False
End Function

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The reason why I am asking if that I create a cconnection exactely the same from the main thread and from a threaded dll, and the cconnection is created using yet another an activex dll, and for some reason, there kind of a "timing problem": When I press Pause in the IDE at some point of time, the main thread can suddenly "see" the cconnection and the records that the threaded lib inserted.
But I have not found out the problem behind it.

This weird "trip" over an additional activex dll is part of my self-disciplining to resolve circular dependencies.

ps: I should perhaps also mention that I use 2 memory-cns at the same time using different names. I am not sure if that is part of the problem.
ps2: Since I remove the 2 other memory cns, it seems to work fine.
ps3: Nope, that was not the problem..

I am currently suspecting that this function in my activex dll is not well placed there:

Code:

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Public Function CreateTH(byval uTaskname as string) as cthreadhandler
  set CreateTh=SomeLogicToEstablishIDAndPathForTheDll(uTaskname)
End Function

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Thank you.

Quote:

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Originally Posted by tmighty2

The reason why I am asking if that I create a cconnection exactely the same from the main thread and from a threaded dll, and the cconnection is created using yet another an activex dll, and for some reason, there kind of a "timing problem": When I press Pause in the IDE at some point of time, the main thread can suddenly "see" the cconnection and the records that the threaded lib inserted.
But I have not found out the problem behind it.

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With such a shared MemDB, you can instantiate a separate cConnection in the main, as well as in each (STA)-thread.
All these separate Connection-Objects then share the same MemDB-allocation - and can "read/write" into it -
(as long as the same virtual file-name is used: as e.g. file:drivescanner?mode=memory&cache=shared)

Your above "problem" (the main-thread can read data, which other AX-Dll-Threads have written into the MemDB,
is exactly "what one tries to achieve" with such a setup... (data-sharing in a mem-area, conveniently accessible from each thread).

Please describe in more detail, what you're trying to accomplish...

Olaf