def gather_sample(self, stat_file):
        # This file format is weird.  Each set of stats is outputted in two
        # lines.  First, a header line that list the field names.  Then a
        # a value line where each value is specified in the appropriate column.
        # You have to match the column name from the header line to determine
        # what that column's value is.  Also, each pair of lines is prefixed
        # with the same name to make it clear they are tied together.
        all_lines = stat_file.readlines()
        # We will create an array of all of the column names in field_names
        # and all of the corresponding values in field_values.
        field_names = []
        field_values = []

        # To simplify the stats, we add together the two forms of retransmit
        # I could find in the netstats.  Those to fast retransmit Reno and those
        # to selective Ack.
        retransmits = 0
        found_retransmit_metric = False

        # Read over lines, looking at adjacent lines.  If their row names match,
        # then append their column names and values to field_names
        # and field_values.  This will break if the two rows are not adjacent
        # but I do not think that happens in practice.  If it does, we just
        # won't report the stats.
        for i in range(0, len(all_lines) - 1):
            names_split = all_lines[i].split()
            values_split = all_lines[i+1].split()
            # Check the row names are the same.
            if names_split[0] == values_split[0] and len(names_split) == len(values_split):
                field_names.extend(names_split)
                field_values.extend(values_split)

        # Now go back and look for the actual stats we care about.
        for i in range(0, len(field_names)):
            if field_names[i] == "InOctets":
                self.print_sample("app.net.bytes", field_values[i], "in")
            elif field_names[i] == "OutOctets":
                self.print_sample("app.net.bytes", field_values[i], "out")
            elif field_names[i] == "TCPRenoRecovery":
                retransmits += int(field_values[i])
                found_retransmit_metric = True
            elif field_names[i] == "TCPSackRecovery":
                retransmits += int(field_values[i])
                found_retransmit_metric = True

        # If we found both forms of retransmit, add them up.
        if found_retransmit_metric:
            self.print_sample("app.net.tcp_retransmits", retransmits)
Returns the list of columns to use in the select statement, as well as
dataset/ETHPy150Open scalyr/scalyr-agent-2/scalyr_agent/builtin_monitors/linux_process_metrics.py/NetStatReader.gather_sample--crossover with--dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/Django-1.6.10/django/db/models/sql/compiler.py/SQLCompiler.get_columns