Merge lp:~percona-toolkit-dev/percona-toolkit/fix-1050737-1075638-ptc-division-by-zero-nibble_time into lp:percona-toolkit/2.1

[Brian Fraser]

[Daniel Nichter (daniel-nichter)]

review: Approve

=== modified file 'bin/pt-table-checksum'
--- bin/pt-table-checksum	2012-11-13 15:22:01 +0000
+++ bin/pt-table-checksum	2012-11-16 01:11:24 +0000
@@ -9391,14 +9391,15 @@
             # Update the rate of rows per second for the entire server.
             # This is used for the initial chunk size of the next table.
             $total_rows += $cnt;
-            $total_time += $tbl->{nibble_time};
-            $total_rate  = int($total_rows / $total_time);
+            $total_time += ($tbl->{nibble_time} || 0);
+            $total_rate  = $total_time ? int($total_rows / $total_time) : 0;
             PTDEBUG && _d('Total avg rate:', $total_rate);
 
             # Adjust chunk size.  This affects the next chunk.
             if ( $o->get('chunk-time') ) {
-               $tbl->{chunk_size}
-                  = $tbl->{rate}->update($cnt, $tbl->{nibble_time});
+               $tbl->{chunk_size} = $tbl->{nibble_time}
+                                  ? $tbl->{rate}->update($cnt, $tbl->{nibble_time})
+                                  : $o->get('chunk-time');
 
                if ( $tbl->{chunk_size} < 1 ) {
                   # This shouldn't happen.  WeightedAvgRate::update() may return
@@ -9414,7 +9415,7 @@
                         . "or increase --chunk-time.  The last chunk, number "
                         . "$chunk of table $tbl->{db}.$tbl->{tbl}, "
                         . "selected $cnt rows and took "
-                        . sprintf('%.3f', $tbl->{nibble_time})
+                        . sprintf('%.3f', $tbl->{nibble_time} || 0)
                         . " seconds to execute.\n");
                   }
                }

=== modified file 't/pt-table-checksum/bugs.t'
--- t/pt-table-checksum/bugs.t	2012-11-08 20:38:04 +0000
+++ t/pt-table-checksum/bugs.t	2012-11-16 01:11:24 +0000
@@ -193,6 +193,40 @@
 );
 
 # #############################################################################
+# Illegal division by zero at pt-table-checksum line 7950
+# https://bugs.launchpad.net/percona-toolkit/+bug/1075638
+# and the ptc part of
+# divison by zero errors on default Gentoo mysql
+# https://bugs.launchpad.net/percona-toolkit/+bug/1050737
+# #############################################################################
+
+{
+   no warnings qw(redefine once);
+   my $orig = \&Time::HiRes::time;
+   my $time = Time::HiRes::time();
+   local *pt_table_checksum::time = local *Time::HiRes::time = sub { $time };
+
+   ($output) = output(
+      sub { pt_table_checksum::main(@args,
+               qw(--replicate=pt.checksums -t test.t --chunk-size 10))
+      },
+      stderr => 1
+   );
+
+   unlike(
+      $output,
+      qr/Illegal division by zero/,
+      "Bugs 1075638 and 1050737: No division by zero error when nibble_time is zero"
+   );
+
+   is(
+      PerconaTest::count_checksum_results($output, 'diffs'),
+      3,
+      "Bug 1075638 and 1050737: ...And we get the correct number of diffs"
+   );
+}
+
+# #############################################################################
 # pt-table-checksum doesn't warn if binlog_format=row or mixed on slaves
 # https://bugs.launchpad.net/percona-toolkit/+bug/938068
 # #############################################################################