Android Question Will Wait For (SenderFilter) sql_NonQueryComplete Work In a Non-UI Program

[rgarnett1955]

Hi,

I have the following query which I am executing as part of a non-ui service:

private Sub insertRecsToTempBuffer(recList As List, tblTempMetaDataArg As tblTemp_Meta_t, N5Arg As Int)

    Dim n As Int = 1
    Dim listN As Int
    listN = recList.Size

    Dim qryStr     As String

    qryStr = _
    $"INSERT INTO tblAgg2SecTemp(
        julianDateUTC, ...
     ...    JdateTime5MinStr)
    VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?);"$
    
    sqlDbAggTemp.BeginTransaction
    'Set up the arguments - values to be inserted
    For Each row() As String In recList
        Dim ArgArray As List
        ArgArray.Initialize
        ArgArray.Add(row(0))...
        ...
        'If we are at the last records then add in the data time - don't do this for all the query is slow
        If n = listN Then
            'Add the time to the last record
            ArgArray.Add(DateTime.Now)  '13
        Else
            ArgArray.Add(0)                '13
        End If
        
        ArgArray.Add(N5Arg) '14
        ArgArray.Add(DateTime.Date(row(3)) & " " & DateTime.Time(row(3))) '15
        ArgArray.Add(jdt.jdDateTimeToDateTimeStr(row(2))) '16
        
        'Insert transaction
        Try
            sqlDbAggTemp.AddNonQueryToBatch(qryStr, ArgArray)
            n = n + 1
        Catch
            closeAllDataBases
            
            Dim LogMsgStr As String = "Insert records into AggTemp query failed"
            setErrRecAndSave(8, listN, -1, LogMsgStr, LastException, True)
        End Try
    Next

    
    'Execute batch insert query
    Dim SenderFilter As Object = sqlDbAggTemp.ExecNonQueryBatch("sql")
    Wait For (SenderFilter) sql_NonQueryComplete (Success As Boolean)

The problem I have is the code does not appear to "Wait For" the query to be complete before continuing on with the rest of the code.

The main program is:

'Non-UI application (console / server application)
#Region Project Attributes
    #CommandLineArgs:
    #MergeLibraries: True
    #AdditionalJar: sqlite-jdbc-3.32.3.2   
#End Region

'============================================================================================
Sub Process_Globals

    Private ipc As ipcComms
    Private dbf As dbFcn
    Private dProc As dataProcControl
End Sub


'============================================================================================
Sub AppStart (Args() As String)
    jdt.initDateTimeConversions("-", ":")
'    ipc.Initialize
    If dbf.Initialize = False Then
        'Handle error TODO
    End If
    
    If dProc.Initialize(dbf) = False Then
        'Handle error TODO
    End If

    StartMessageLoop
End Sub


'============================================================================================
Sub doAgg As Boolean
    dbf.doAggregate 'This calls the query function '
End Sub

I wish to use the async query to make the program responsive to network requests.

Am I doing something wrong and do I need to create a separate thread for the network interface and use non async queries?

I noticed that the sleep(10000) statement in the simple example program below doesn't provide a ten second delay.

'Non-UI application (console / server application)
#Region Project Attributes
    #CommandLineArgs:
    #MergeLibraries: True
#End Region

Sub Process_Globals
    
End Sub

Sub AppStart (Args() As String)
    Log("Start")
    Log("BeforeWrapper")
    wrapper
    Log("AfterWrapper")
    
    StartMessageLoop
End Sub

Sub wrapper
    Log("Before Sum")
    Sum(10, 20)
    Log("After Sum")
End Sub

Sub Sum(x As Int, y As Int)
    Log(x)
    Sleep(10000)
    Log("Sum = " & (x + y))
End Sub

Best regards
Rob

 

[OliverA]

I noticed that the sleep(10000) statement in the simple example program below doesn't provide a ten second delay.

What gives you that impression? The immediate printing of “AfterWrapper”? That’s a given and works as intended.

 

[rgarnett1955]

What gives you that impression? The immediate printing of “AfterWrapper”? That’s a given and works as intended.

You are correct,

I had a senior's moment.

But my asynch query doesn't seem to work.

I get some data but when I set a break point on the statement immediately after the =>

Wait For (SenderFilter) sql_NonQueryComplete (Success As Boolean)

It never get there but hits break points set later in the calling function.

Works fine if i avoid async queries.

I might cook up a simple example program. The program I'm working on is too complex to post and the source data-base is 23 GB.

Best regards
Rob

 

[Erel]

The answer is: yes. The async methods work exactly the same as in UI apps, you just need to call StartMessageLoop.

Note that you shouldn't create a transaction yourself here. A transaction is created internally.