Fix for 1176010: pt-query-digest should know how to group quoted and unquoted database names

bin/pt-query-digest

@@ -12940,13 +12940,16 @@ sub main {
 
             return [ grep { $_->[0] != $cxn } @{ $sth->fetchall_arrayref(); } ];
          };
-
+         
          $pipeline->add(
             name    => ref $pl,
             process => sub {
                my ( $args ) = @_;
                my $event = $pl->parse_event(code => $code);
-               $args->{event} = $event if $event;
+               if ( $event ) {
+                  sanitize_event($event);
+                  $args->{event} = $event;
+               }
                return $args;
             },
          );
@@ -13006,6 +13009,7 @@ sub main {
                         stats       => $args->{stats},
                      );
                      if ( $event ) {
+                        sanitize_event($event);
                         $args->{event} = $event;
                         return $args;
                      }
@@ -14229,6 +14233,17 @@ sub save_resume_offset {
    return;
 }
 
+# Quoted and unquoted values should be treated the same
+# See https://bugs.launchpad.net/percona-toolkit/+bug/1176010
+sub sanitize_event {
+   my ($event) = @_;
+   foreach my $value ( values %$event ) {
+      if ( $value && $value =~ /\A`(.+)`\z/sm ) {
+         $value = $1
+      }
+   }
+}
+
 sub _d {
    my ($package, undef, $line) = caller 0;
    @_ = map { (my $temp = $_) =~ s/\n/\n# /g; $temp; }

t/lib/samples/slowlogs/slow057.txt

@@ -0,0 +1,23 @@
+# User@Host: meow[meow] @  [1.2.3.8]
+# Thread_id: 5  Schema: db
+# Query_time: 0.000002  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+# No InnoDB statistics available for this query
+# administrator command: Quit;
+# User@Host: meow[meow] @  [1.2.3.8]
+# Thread_id: 6  Schema: db2 
+# Query_time: 0.000899  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+# No InnoDB statistics available for this query
+use db;
+SET NAMES utf8;
+# User@Host: meow[meow] @  [1.2.3.8]
+# Thread_id: 7  Schema: db
+# Query_time: 0.018799  Lock_time: 0.009453  Rows_sent: 0  Rows_examined: 0
+# No InnoDB statistics available for this query
+use `db`;
+# administrator command: Quit;
+# User@Host: meow[meow] @  [1.2.3.8]
+# Thread_id: 9  Schema: db2 
+# Query_time: 0.000899  Lock_time: 0.000000  Rows_sent: 0  Rows_examined: 0
+# No InnoDB statistics available for this query
+use db;
+SET NAMES utf8;

t/pt-query-digest/samples/slow057.txt

@@ -0,0 +1,52 @@
+
+# Query 1: 0 QPS, 0x concurrency, ID 0xAA353644DE4C4CB4 at byte 434 ______
+# This item is included in the report because it matches --limit.
+# Scores: V/M = 0.02
+# Attribute    pct   total     min     max     avg     95%  stddev  median
+# ============ === ======= ======= ======= ======= ======= ======= =======
+# Count         50       2
+# Exec time     91    19ms     2us    19ms     9ms    19ms    13ms     9ms
+# Lock time    100     9ms       0     9ms     5ms     9ms     7ms     5ms
+# Rows sent      0       0       0       0       0       0       0       0
+# Rows examine   0       0       0       0       0       0       0       0
+# Query size    65      54      27      27      27      27       0      27
+# String:
+# Databases    db
+# Hosts
+# Users        meow
+# Query_time distribution
+#   1us  ################################################################
+#  10us
+# 100us
+#   1ms
+#  10ms  ################################################################
+# 100ms
+#    1s
+#  10s+
+administrator command: Quit\G
+
+# Query 2: 0 QPS, 0x concurrency, ID 0xCC47B42511EA22DD at byte 662 ______
+# This item is included in the report because it matches --limit.
+# Scores: V/M = 0.00
+# Attribute    pct   total     min     max     avg     95%  stddev  median
+# ============ === ======= ======= ======= ======= ======= ======= =======
+# Count         50       2
+# Exec time      8     2ms   899us   899us   899us   899us       0   899us
+# Lock time      0       0       0       0       0       0       0       0
+# Rows sent      0       0       0       0       0       0       0       0
+# Rows examine   0       0       0       0       0       0       0       0
+# Query size    34      28      14      14      14      14       0      14
+# String:
+# Databases    db
+# Hosts
+# Users        meow
+# Query_time distribution
+#   1us
+#  10us
+# 100us  ################################################################
+#   1ms
+#  10ms
+# 100ms
+#    1s
+#  10s+
+SET NAMES utf8\G

t/pt-query-digest/slowlog_analyses.t

@@ -393,6 +393,18 @@ ok(
    'Analysis for slow056 (no query bug 1082599)'
 );
 
+# #############################################################################
+# Bug 1176010: pt-query-digest should know how to group quoted and unquoted database names
+# https://bugs.launchpad.net/percona-toolkit/+bug/1176010
+#############################################################################
+ok(
+   no_diff(
+      sub { pt_query_digest::main(@args, $sample.'slow057.txt') },
+      "t/pt-query-digest/samples/slow057.txt",
+   ),
+   'Analysis for slow057 (no grouping bug 1176010)'
+);
+
 # #############################################################################
 # Done.
 # #############################################################################