Transactions in vb.net locks table and SELECT gets timeout - sql

Question

I have the following problem:
Inside one sqltransaction in vb.net I INSERT data into several tables.
it is something like this:
...
sqltransaction = connection.begintransaction
INSERT into table1
...
for i=1 to x
...
INSERT into table2
...
SELECT FROM table3
...
INSERT into table3
...
next i
sqltransaction.commit
...
Private Sub salveazaCerereaDeOferta()
If checkCompletion() = 1 Then
Dim conn As New SqlConnection(My.Settings.GestiuneService2012_beSQLConnectionString)
conn.Open()
Dim sqlTrans As SqlTransaction = conn.BeginTransaction()
Try
Dim cmdInsertCerereOferta As SqlCommand = conn.CreateCommand
cmdInsertCerereOferta.Transaction = sqlTrans
cmdInsertCerereOferta.CommandText = "INSERT INTO ListaCereriOferte (IDFurnizor,NrCerereOferta,DataCerereOferta,IDModTransCerereOferta,ObservatiiCerereOferta)" + _
" VALUES (#IDFurnizor,#NrCerereOferta,#DataCerereOferta,#IDModTransCerereOferta,#ObservatiiCerereOferta);" + _
" SELECT SCOPE_IDENTITY();"
cmdInsertCerereOferta.Parameters.Add("#IDFurnizor", SqlDbType.Int).Value = CInt(Me.t_IDFurnizor.Text)
cmdInsertCerereOferta.Parameters.Add("#NrCerereOferta", SqlDbType.Int).Value = CInt(Me.t_NumarCerereOferta.Text)
cmdInsertCerereOferta.Parameters.Add("#DataCerereOferta", SqlDbType.Date).Value = CDate(Me.t_DataCerereOferta.Text)
cmdInsertCerereOferta.Parameters.Add("#IDModTransCerereOferta", SqlDbType.Int).Value = 1
cmdInsertCerereOferta.Parameters.Add("#ObservatiiCerereOferta", SqlDbType.NVarChar).Value = Me.t_ObservatiiCerereOferta.Text
Dim IDCerereOferta As Integer = cmdInsertCerereOferta.ExecuteScalar
Dim ListaPieseCerereOferta = Me.CerereOfertaDataSet.ListaPieseCerereOferta.AsEnumerable
Dim ListaNecesarePePiesa = Me.CerereOfertaDataSet.NecesarePeOferta.AsEnumerable
Dim PieseOferta = From q In ListaPieseCerereOferta _
Select q
Dim cantTotalaPiese = Aggregate q In ListaPieseCerereOferta _
Into Sum(q.Cantitate)
Dim salvat As Integer = 0
Dim curIDPiesaDeSchimb As Integer
For Each piesa In PieseOferta
curIDPiesaDeSchimb = piesa.IDPiesaDeSchimb
Dim NecesarePePiesa = From p In ListaNecesarePePiesa _
Select p _
Order By p.IDNecesar Descending
Dim curIDNecesar As Integer
For Each necesar In NecesarePePiesa
curIDNecesar = necesar.IDNecesar
Dim cmdInsertPiesaCerereOferta As SqlCommand = conn.CreateCommand
cmdInsertPiesaCerereOferta.Transaction = sqlTrans
cmdInsertPiesaCerereOferta.CommandText = "INSERT INTO CereriOferte (IDCerereOferta,IDPiesaDeSchimb,Cantitate,UM,Observatii)" + _
" VALUES (#IDCerereOferta,#IDPiesaDeSchimb,#Cantitate,#UM,#Observatii);" + _
" SELECT SCOPE_IDENTITY();"
cmdInsertPiesaCerereOferta.Parameters.Add("#IDCerereOferta", SqlDbType.Int)
cmdInsertPiesaCerereOferta.Parameters.Add("#IDPiesaDeSchimb", SqlDbType.Int)
cmdInsertPiesaCerereOferta.Parameters.Add("#Cantitate", SqlDbType.Float)
cmdInsertPiesaCerereOferta.Parameters.Add("#UM", SqlDbType.NVarChar)
cmdInsertPiesaCerereOferta.Parameters.Add("#Observatii", SqlDbType.NVarChar)
Dim cmdInsertNecesarCerereOferta As SqlCommand = conn.CreateCommand
cmdInsertNecesarCerereOferta.Transaction = sqlTrans
cmdInsertNecesarCerereOferta.CommandText = "INSERT INTO NecesareCereriOferte (IDPiesaNecesar,IDPiesaCerereOferta)" + _
" VALUES (#IDPiesaNecesar,#IDPiesaCerereOferta)"
cmdInsertNecesarCerereOferta.Parameters.Add("#IDPiesaNecesar", SqlDbType.Int)
cmdInsertNecesarCerereOferta.Parameters.Add("#IDPiesaCerereOferta", SqlDbType.Int)
Select Case curIDNecesar
Case 0
cmdInsertPiesaCerereOferta.Parameters("#IDCerereOferta").Value = IDCerereOferta
cmdInsertPiesaCerereOferta.Parameters("#IDPiesaDeSchimb").Value = curIDPiesaDeSchimb
cmdInsertPiesaCerereOferta.Parameters("#Cantitate").Value = 1
cmdInsertPiesaCerereOferta.Parameters("#UM").Value = piesa.UM
cmdInsertPiesaCerereOferta.Parameters("#Observatii").Value = ""
For i = 1 To necesar.Cantitate
cmdInsertPiesaCerereOferta.ExecuteNonQuery()
salvat += 1
Me.tsspb_SalvareCerereOferta.Value = CInt(100 * salvat / cantTotalaPiese)
Next
Case Is > 0
Me.PieseNecesarePeOfertaTableAdapter.Fill(Me.CerereOfertaDataSet.PieseNecesarePeOferta, curIDNecesar, curIDPiesaDeSchimb, CInt(necesar.Cantitate))
Dim ListaPieseNecesarePeOferta = Me.CerereOfertaDataSet.PieseNecesarePeOferta.AsEnumerable
Dim PieseNecesareOferta = From q In ListaPieseNecesarePeOferta _
Select q
For i = 1 To necesar.Cantitate
cmdInsertPiesaCerereOferta.Parameters("#IDCerereOferta").Value = IDCerereOferta
cmdInsertPiesaCerereOferta.Parameters("#IDPiesaDeSchimb").Value = curIDPiesaDeSchimb
cmdInsertPiesaCerereOferta.Parameters("#Cantitate").Value = 1
cmdInsertPiesaCerereOferta.Parameters("#UM").Value = piesa.UM
cmdInsertPiesaCerereOferta.Parameters("#Observatii").Value = ""
Dim insertedIDPiesaCerereOferta As Integer = cmdInsertPiesaCerereOferta.ExecuteScalar
cmdInsertNecesarCerereOferta.Parameters("#IDPiesaNecesar").Value = PieseNecesareOferta(i - 1).IDPiesaNecesar
cmdInsertNecesarCerereOferta.Parameters("#IDPiesaCerereOferta").Value = insertedIDPiesaCerereOferta
cmdInsertNecesarCerereOferta.ExecuteNonQuery()
salvat += 1
Me.tsspb_SalvareCerereOferta.Value = CInt(100 * salvat / cantTotalaPiese)
Next
End Select
Next
Next
sqlTrans.Commit()
MsgBox("Cererea de oferta a fost salvata.")
Catch ex As Exception
Try
sqlTrans.Rollback()
MsgBox("A aparut o eroare." + vbNewLine + ex.ToString + vbNewLine + "RollBack success. Cererea nu a fost salvata.")
Catch ex2 As SqlException
If Not sqlTrans.Connection Is Nothing Then
MsgBox("An exception of type " & ex2.GetType().ToString() & _
" was encountered while attempting to roll back the transaction.")
End If
End Try
Finally
If conn.State = ConnectionState.Open Then conn.Close()
End Try
Else
MsgBox("Nu ai completat integral cererea de oferta!")
End If
End Sub
query that locks:
SELECT TOP (100) PERCENT dbo.qry_NecesareNerezolvate.IDPiesaNecesar, COUNT(dbo.NecesareCereriOferte.IDPiesaCerereOferta) AS CereriOferte,
dbo.qry_NecesareNerezolvate.IDNecesar, dbo.qry_NecesareNerezolvate.IDPiesaDeSchimb, dbo.qry_NecesareNerezolvate.Cantitate
FROM dbo.qry_NecesareNerezolvate LEFT OUTER JOIN
dbo.NecesareCereriOferte ON dbo.qry_NecesareNerezolvate.IDPiesaNecesar = dbo.NecesareCereriOferte.IDPiesaNecesar
GROUP BY dbo.qry_NecesareNerezolvate.IDPiesaNecesar, dbo.qry_NecesareNerezolvate.IDNecesar, dbo.qry_NecesareNerezolvate.IDPiesaDeSchimb,
dbo.qry_NecesareNerezolvate.Cantitate
qry_NecesareNerezolvate:
SELECT TOP (100) PERCENT dbo.Necesare.IDPiesaNecesar, dbo.Necesare.IDNecesar, dbo.Necesare.IDPiesaDeSchimb, dbo.Necesare.Cantitate, dbo.Necesare.UM,
dbo.Necesare.Observatii
FROM dbo.Necesare LEFT OUTER JOIN
dbo.qry_NecesareComandateRezolvate ON dbo.Necesare.IDPiesaNecesar = dbo.qry_NecesareComandateRezolvate.IDPiesaNecesar
WHERE (dbo.qry_NecesareComandateRezolvate.IDPiesaNecesar IS NULL)
qry_NecesareComandateRezolvate:
SELECT dbo.Necesare.IDPiesaNecesar, dbo.NecesareComenzi.IDPiesaComanda, dbo.NecesareRezolvate.IDBonTransfer
FROM dbo.Necesare LEFT OUTER JOIN
dbo.NecesareComenzi ON dbo.Necesare.IDPiesaNecesar = dbo.NecesareComenzi.IDPiesaNecesar LEFT OUTER JOIN
dbo.NecesareRezolvate ON dbo.Necesare.IDPiesaNecesar = dbo.NecesareRezolvate.IDPiesaNecesar
WHERE (dbo.NecesareComenzi.IDPiesaComanda IS NOT NULL) OR
(dbo.NecesareRezolvate.IDBonTransfer IS NOT NULL)
for i=1: insert, select then insert is working
then i=2 and: INSERT into table2... is working but SELECT FROM table1 and table3... gets timeout...
I don't understand why!
PS: If I break the code before second run of SELECT FROM table3 then go to SSMS and run the select query it gets timeout too...

Answer 1

In your code sample below, you have the transaction open till the end of the For Loop.
It seems to me that when i =1 , the transaction gets opened and a insertion is made. Now when i=2 , the to be inserted row when i=1 is in uncomitted state and if your select is joining to the table1 the lock level would have escalated to table level and locked everything down. Move the commit to inside the for loop and check how it goes.
for i=1 to x
...
INSERT into table2
...
SELECT FROM table3
...
INSERT into table3
...
next i
sqltransaction.commit