Fix bug 1217013: exact dupe unique keys not detected.

lib/DuplicateKeyFinder.pm

@@ -143,8 +143,6 @@ sub get_duplicate_keys {
    push @dupes,
       $self->remove_prefix_duplicates(\@fulltext_keys, \@fulltext_keys, %args, exact_duplicates => 1);
 
-   # TODO: other structs
-
    # Remove clustered duplicates.
    my $clustered_key = $args{clustered_key} ? $keys{$args{clustered_key}}
                      : undef;
@@ -314,7 +312,7 @@ sub remove_prefix_duplicates {
          if (    substr($left_cols,  0, $right_len_cols)
               eq substr($right_cols, 0, $right_len_cols) ) {
 
-            # FULLTEXT keys, for example, are only duplicates if they
+            # UNIQUE and FULLTEXT indexes are only duplicates if they
             # are exact duplicates.
             if ( $args{exact_duplicates} && ($right_len_cols<$left_len_cols) ) {
                PTDEBUG && _d($right_name, 'not exact duplicate of', $left_name);
@@ -333,10 +331,10 @@ sub remove_prefix_duplicates {
 
             PTDEBUG && _d('Remove', $right_name);
             my $reason;
-            if ( $right_keys->[$right_index]->{unconstrained} ) {
+            if ( my $type = $right_keys->[$right_index]->{unconstrained} ) {
                $reason .= "Uniqueness of $right_name ignored because "
                   . $right_keys->[$right_index]->{constraining_key}->{name}
-                  . " is a stronger constraint\n"; 
+                  . " is a $type constraint\n"; 
             }
             my $exact_dupe = $right_len_cols < $left_len_cols ? 0 : 1;
             $reason .= $right_name
@@ -454,14 +452,23 @@ sub unconstrain_keys {
       next unless $unique_key; # primary key may be undefined
       my $cols = $unique_key->{cols};
       if ( @$cols == 1 ) {
-         PTDEBUG && _d($unique_key->{name},'defines unique column:',$cols->[0]);
-         # Save only the first unique key for the unique col. If there
-         # are others, then they are exact duplicates and will be removed
-         # later when unique keys are compared to unique keys.
          if ( !exists $unique_cols{$cols->[0]} ) {
+            PTDEBUG && _d($unique_key->{name}, 'defines unique column:',
+               $cols->[0]);
             $unique_cols{$cols->[0]}  = $unique_key;
             $unique_key->{unique_col} = 1;
          }
+         else {
+            # https://bugs.launchpad.net/percona-toolkit/+bug/1217013
+            # If two unique indexes are not exact, then they must be enforcing
+            # different uniqueness constraints.  Else they're exact dupes
+            # so one can be treated as a non-unique and removed later
+            # when comparing unique to non-unique.
+            PTDEBUG && _d($unique_key->{name},
+               'redundantly constrains unique column:', $cols->[0]);
+            $unique_key->{exact_dupe} = 1;
+            $unique_key->{constraining_key} = $unique_cols{$cols->[0]};
+         }
       }
       else {
          local $LIST_SEPARATOR = '-';
@@ -496,18 +503,25 @@ sub unconstrain_keys {
       }
    }
 
-   # And finally, unconstrain the redudantly unique sets found above by
+   # And finally, unconstrain the redundantly unique sets found above by
    # removing them from the list of unique keys and adding them to the
    # list of normal keys.
    for my $i ( 0..(scalar @$unique_keys-1) ) {
       if ( exists $unconstrain{$unique_keys->[$i]->{name}} ) {
-         PTDEBUG && _d('Unconstraining', $unique_keys->[$i]->{name});
+         PTDEBUG && _d('Unconstraining weak', $unique_keys->[$i]->{name});
-         $unique_keys->[$i]->{unconstrained} = 1;
+         $unique_keys->[$i]->{unconstrained} = 'stronger';
          $unique_keys->[$i]->{constraining_key}
             = $unconstrain{$unique_keys->[$i]->{name}};
          push @unconstrained_keys, $unique_keys->[$i];
          delete $unique_keys->[$i];
       }
+      elsif ( $unique_keys->[$i]->{exact_dupe} ) {
+         # https://bugs.launchpad.net/percona-toolkit/+bug/1217013
+         PTDEBUG && _d('Unconstraining dupe', $unique_keys->[$i]->{name});
+         $unique_keys->[$i]->{unconstrained} = 'duplicate';
+         push @unconstrained_keys, $unique_keys->[$i];
+         delete $unique_keys->[$i];
+      }
    }
 
    PTDEBUG && _d('No more keys');

t/lib/DuplicateKeyFinder.t

@@ -757,7 +757,7 @@ is_deeply(
        duplicate_of_cols => [ 'row_id' ],
        duplicate_of_ddl  => 'PRIMARY KEY (`row_id`),',
        key               => 'row_id',
-       reason            => 'row_id is a duplicate of PRIMARY',
+       reason            => "Uniqueness of row_id ignored because PRIMARY is a duplicate constraint\nrow_id is a duplicate of PRIMARY",
      },
      {
        cols              => [ 'player_id' ],
@@ -803,6 +803,35 @@ is_deeply(
 #   "Prefix bug 1214114"
 #) or diag(Dumper($dupes));
 
+# #############################################################################
+# https://bugs.launchpad.net/percona-toolkit/+bug/1217013
+ #############################################################################
+$ddl   = load_file('t/lib/samples/dupekeys/simple_dupe_bug_1217013.sql');
+$dupes = [];
+($keys, $ck) = $tp->get_keys($ddl, $opt);
+$dk->get_duplicate_keys(
+   $keys,
+   clustered_key => $ck,
+   clustered     => 1,
+   callback      => $callback,
+   tbl_info      => { engine => 'InnoDB', ddl => $ddl },
+);
+
+is_deeply(
+   $dupes,
+   [{
+      cols              => ['domain'],
+      ddl               => 'UNIQUE KEY `domain` (`domain`),',
+      dupe_type         => 'exact',
+      duplicate_of      => 'unique_key_domain',
+      duplicate_of_cols => ['domain'],
+      duplicate_of_ddl  => 'UNIQUE KEY `unique_key_domain` (`domain`)',
+      key               => 'domain',
+      reason            => "Uniqueness of domain ignored because unique_key_domain is a duplicate constraint\ndomain is a duplicate of unique_key_domain",
+   }],
+   "Exact dupe uniques (bug 1217013)"
+) or diag(Dumper($dupes));
+
 # #############################################################################
 # Done.
 # #############################################################################

t/lib/samples/dupekeys/simple_dupe_bug_1217013.sql

@@ -0,0 +1,7 @@
+CREATE TABLE `domains` (
+  `id` bigint(20) NOT NULL,
+  `domain` varchar(175) COLLATE utf8_bin NOT NULL,
+  PRIMARY KEY (`id`),
+  UNIQUE KEY `domain` (`domain`),
+  UNIQUE KEY `unique_key_domain` (`domain`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin