Merge pull request #988 from percona/PT-2052_Tools_should_default_to_unbuffered_stdout_stderr

Pt 2052 tools should default to unbuffered stdout stderr

bin/pt-align

@@ -528,6 +528,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -1266,6 +1270,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 =over
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --help
 
 Show help and exit.

bin/pt-archiver

@@ -1257,6 +1257,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -7769,6 +7773,13 @@ The danger is that a crash might cause lost data.
 The performance increase I have seen from using L<"--buffer"> is around 5 to 15
 percent.  Your mileage may vary.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --bulk-delete
 
 Delete each chunk with a single statement (implies L<"--commit-each">).

bin/pt-config-diff

@@ -1255,6 +1255,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -5738,6 +5742,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-deadlock-logger

@@ -605,6 +605,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -5336,6 +5340,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-diskstats

@@ -601,6 +601,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -5474,6 +5478,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 =over
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --columns-regex
 
 type: string; default: .

bin/pt-duplicate-key-checker

@@ -1660,6 +1660,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -5451,6 +5455,13 @@ as a FULLTEXT index is not really a duplicate, for example.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-fifo-split

@@ -529,6 +529,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -1567,6 +1571,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 =over
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --config
 
 type: Array

bin/pt-find

@@ -1048,6 +1048,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -4562,6 +4566,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --case-insensitive
 
 Specifies that all regular expression searches are case-insensitive.

bin/pt-fingerprint

@@ -530,6 +530,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -2137,6 +2141,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 =over
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --config
 
 type: Array

bin/pt-fk-error-logger

@@ -600,6 +600,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -4459,6 +4463,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-heartbeat

@@ -1558,6 +1558,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -7102,6 +7106,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-index-usage

@@ -1214,6 +1214,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -7200,6 +7204,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-kill

@@ -610,6 +610,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -8005,6 +8009,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-online-schema-change

@@ -667,6 +667,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -12923,6 +12927,13 @@ This is useful when you change large tables with keys that include a binary
 data type or that have non-standard character sets.
 See L<"--history"> and L<"--resume">.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --channel
 
 type: string

bin/pt-query-digest

@@ -1882,6 +1882,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -15699,6 +15703,13 @@ values for attributes.  If the attribute's value is bigger than this, the
 last-seen value for that class of query is used instead.
 Disabled by default.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-replica-find

@@ -538,6 +538,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -4404,6 +4408,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-replica-restart

@@ -760,6 +760,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -5910,6 +5914,13 @@ pt-replica-restart will not let you stop the replica manually if you want to!
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-show-grants

@@ -531,6 +531,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -2402,6 +2406,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-slave-delay

@@ -604,6 +604,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }

bin/pt-table-checksum

@@ -2364,6 +2364,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -13306,6 +13310,13 @@ group: Connection
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --channel
 
 type: string

bin/pt-table-sync

@@ -618,6 +618,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -12492,6 +12496,13 @@ For most non-trivial data sizes, you want to leave this option enabled.
 
 This option is disabled when L<"--bidirectional"> is used.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --channel
 
 type: string

bin/pt-table-usage

@@ -1650,6 +1650,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -8259,6 +8263,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-upgrade

@@ -1879,6 +1879,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -11091,6 +11095,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-variable-advisor

@@ -607,6 +607,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -6100,6 +6104,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

bin/pt-visual-explain

@@ -1217,6 +1217,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }
@@ -3946,6 +3950,13 @@ L<"SYNOPSIS"> and usage information for details.
 
 Prompt for a password when connecting to MySQL.
 
+=item --[no]buffer-stdout
+
+default: yes
+
+Enables STDOUT buffering. Disable this option if you want to see live progress
+when using output post-processing tools such as C<tee> or C<kubectl logs>.
+
 =item --charset
 
 short form: -A; type: string

lib/OptionParser.pm

@@ -668,6 +668,10 @@ sub get_opts {
       }
    }
 
+   if ( exists $self->{opts}->{'buffer-stdout'} && $self->{opts}->{'buffer-stdout'}->{got} ) {
+      STDOUT->autoflush(1 - $self->{opts}->{'buffer-stdout'}->{value});
+   }
+
    if ( @ARGV && $self->{strict} ) {
       $self->save_error("Unrecognized command-line options @ARGV");
    }

t/pt-table-checksum/pt-2052.t

@@ -0,0 +1,112 @@
+#!/usr/bin/env perl
+
+BEGIN {
+   die "The PERCONA_TOOLKIT_BRANCH environment variable is not set.\n"
+      unless $ENV{PERCONA_TOOLKIT_BRANCH} && -d $ENV{PERCONA_TOOLKIT_BRANCH};
+   unshift @INC, "$ENV{PERCONA_TOOLKIT_BRANCH}/lib";
+};
+
+use strict;
+use warnings FATAL => 'all';
+use English qw(-no_match_vars);
+use Test::More;
+use Time::Local;
+
+use PerconaTest;
+use Sandbox;
+require "$trunk/bin/pt-table-checksum";
+
+my $dp  = new DSNParser(opts=>$dsn_opts);
+my $sb  = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $dbh = $sb->get_dbh_for('source');
+
+my $output = `$trunk/bin/pt-table-checksum h=127.1,P=12345,u=msandbox,p=msandbox --set-vars innodb_lock_wait_timeout=3 --chunk-size=50 -d sakila --buffer-stdout 2>&1 | tee | ts '%m-%dT%H:%M:%S'`;
+
+my @lines = split(/\n/, $output);
+my @times = ( $lines[3] =~ m/\d\d-\d\dT\d\d:\d\d:\d\d/g );
+
+is(
+   scalar(@times),
+   2,
+   "Expected number of timestamp values"
+) or diag($output);
+
+my ($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[0]);
+my $time_ts = timelocal($sec, $min, $hour, $day, $month);
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[1]);
+my $time_tool = timelocal($sec, $min, $hour, $day, $month);
+
+cmp_ok(
+   $time_ts - $time_tool, 'gt', 1,
+   "Print delay is expected for the buffered output"
+) or diag($output); 
+
+$output = `$trunk/bin/pt-table-checksum h=127.1,P=12345,u=msandbox,p=msandbox --set-vars innodb_lock_wait_timeout=3 --chunk-size=50 -d sakila 2>&1 | tee | ts '%m-%dT%H:%M:%S'`;
+
+@lines = split(/\n/, $output);
+@times = ( $lines[3] =~ m/\d\d-\d\dT\d\d:\d\d:\d\d/g );
+
+is(
+   scalar(@times),
+   2,
+   "Expected number of timestamp values"
+) or diag($output);
+
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[0]);
+$time_ts = timelocal($sec, $min, $hour, $day, $month);
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[1]);
+$time_tool = timelocal($sec, $min, $hour, $day, $month);
+
+cmp_ok(
+   $time_ts - $time_tool, 'gt', 1,
+   "STDOUT is buffered by default"
+) or diag($output); 
+
+$output = `$trunk/bin/pt-table-checksum h=127.1,P=12345,u=msandbox,p=msandbox --set-vars innodb_lock_wait_timeout=3 --chunk-size=50 -d sakila --no-buffer-stdout 2>&1 | tee | ts '%m-%dT%H:%M:%S'`;
+
+@lines = split(/\n/, $output);
+@times = ( $lines[3] =~ m/\d\d-\d\dT\d\d:\d\d:\d\d/g );
+
+is(
+   scalar(@times),
+   2,
+   "Expected number of timestamp values"
+) or diag($output);
+
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[0]);
+$time_ts = timelocal($sec, $min, $hour, $day, $month);
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[1]);
+$time_tool = timelocal($sec, $min, $hour, $day, $month);
+
+cmp_ok(
+   $time_ts - $time_tool, 'le', 1,
+   "Print delay is not expected when buffering is disabled"
+) or diag($output); 
+
+$output = `$trunk/bin/pt-table-checksum h=127.1,P=12345,u=msandbox,p=msandbox --set-vars innodb_lock_wait_timeout=3 --chunk-size=50 -d sakila --nobuffer-stdout 2>&1 | tee | ts '%m-%dT%H:%M:%S'`;
+
+@lines = split(/\n/, $output);
+@times = ( $lines[3] =~ m/\d\d-\d\dT\d\d:\d\d:\d\d/g );
+
+is(
+   scalar(@times),
+   2,
+   "Expected number of timestamp values"
+) or diag($output);
+
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[0]);
+$time_ts = timelocal($sec, $min, $hour, $day, $month);
+($month, $day, $hour, $min, $sec) = split(/[T:-]+/, $times[1]);
+$time_tool = timelocal($sec, $min, $hour, $day, $month);
+
+cmp_ok(
+   $time_ts - $time_tool, 'le', 1,
+   "Test 2: Print delay is not expected when buffering is disabled"
+) or diag($output); 
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;