I have three calenders that display booked dates for the span of 3 months. When I try to connect to database (sql server), I encountered this error;

Timeout expired.  The timeout period elapsed prior to obtaining a connection from the pool.  This may have occurred because all pooled connections were in use and max pool size was reached.

My code:

    Protected Sub bookSchedule3_DayRender(sender As Object, e As DayRenderEventArgs) Handles bookSchedule3.DayRender
        strSQL = "SELECT bookDate FROM booking"
        Call runQ(strSQL)

        Dim dschkDate As New DataSet
        dschkDate.Clear()
        sqlAdap.Fill(dschkDate, "booking")

        If e.Day.Date.CompareTo(Convert.ToDateTime(dschkDate.Tables(0).Rows(0).Item("bookDate").ToString.Trim)) = 0 Then
            e.Day.IsSelectable = False
            e.Cell.BackColor = System.Drawing.Color.Transparent
            e.Cell.ForeColor = System.Drawing.Color.Transparent
        End If
    End Sub

I tried adding max pool but it didn't fix the error. I hope there is a way to solve this and am willing to learn other ways if necessary.