+=item I<$obj>-E<gt>B<flush> (B<timeout> =E<gt> I<$timeout>, B<plugins> =E<gt> [...], B<identifier> =E<gt> [...]);
+
+Flush cached data.
+
+Valid options are:
+
+=over 4
+
+=item B<timeout>
+
+If this option is specified, only data older than I<$timeout> seconds is
+flushed.
+
+=item B<plugins>
+
+If this option is specified, only the selected plugins will be flushed. The
+argument is a reference to an array of strings.
+
+=item B<identifier>
+
+If this option is specified, only the given identifier(s) will be flushed. The
+argument is a reference to an array of identifiers. Identifiers, in this case,
+are hash references and have the members as outlined in L<VALUE IDENTIFIERS>.
+
+=back
+
+=cut
+
+sub flush
+{
+ my $obj = shift;
+ my %args = @_;
+
+ my $fh = $obj->{'sock'} or confess;
+
+ my $status = 0;
+ my $msg = "FLUSH";
+
+ if (defined ($args{'timeout'}))
+ {
+ $msg .= " timeout=" . $args{'timeout'};
+ }
+
+ if ($args{'plugins'})
+ {
+ foreach my $plugin (@{$args{'plugins'}})
+ {
+ $msg .= " plugin=" . $plugin;
+ }
+ }
+
+ if ($args{'identifier'})
+ {
+ for (@{$args{'identifier'}})
+ {
+ my $identifier = $_;
+ my $ident_str;
+
+ if (ref ($identifier) ne 'HASH')
+ {
+ cluck ("The argument of the `identifier' "
+ . "option must be an array reference "
+ . "of hash references.");
+ return;
+ }
+
+ $ident_str = _create_identifier ($identifier);
+ if (!$ident_str)
+ {
+ return;
+ }
+
+ $msg .= ' identifier=' . _escape_argument ($ident_str);
+ }
+ }
+
+ $msg .= "\n";
+
+ send ($fh, $msg, 0) or confess ("send: $!");
+ $msg = undef;
+ recv ($fh, $msg, 1024, 0) or confess ("recv: $!");
+
+ ($status, $msg) = split (' ', $msg, 2);
+ return (1) if ($status == 0);
+
+ $obj->{'error'} = $msg;
+ return;
+}
+