Merge fix-938068-ptc-slave-binlog-formats

bin/pt-table-checksum

@@ -8586,6 +8586,26 @@ sub main {
       );
       PTDEBUG && _d(scalar @$slaves, 'slaves found');
 
+      # https://bugs.launchpad.net/percona-toolkit/+bug/938068
+      if ( $o->get('check-binlog-format') ) {
+         my ($master_binlog) = $master_dbh->selectrow_array(
+            'SELECT @@binlog_format');
+         my $err = '';
+         for my $slave_cxn (@$slaves) {
+            my ($slave_binlog) = $slave_cxn->dbh->selectrow_array(
+               'SELECT @@binlog_format');
+            if ( $master_binlog ne $slave_binlog ) {
+               $err .= $master_cxn->name() . " has binlog_format "
+                  . $master_binlog . " but replica " . $slave_cxn->name()
+                  . " has binlog_format $slave_binlog.  This could cause "
+                  . "pt-table-checksum to break replication.  "
+                  . "If understand the risks, specify "
+                  .  "--no-check-binlog-format to disable this check.\n";
+            }
+         }
+         die $err if $err;
+      }
+
       if ( $master_cxn->is_cluster_node() && !@$slaves ) {
          die $master_cxn->name() . " is a cluster node but no other nodes "
             . "or regular replicas were found.  Use --recursion-method=dsn "
@@ -10506,6 +10526,14 @@ type: time; default: 1; group: Throttle
 
 Sleep time between checks for L<"--max-lag">.
 
+=item --[no]check-binlog-format
+
+default: yes
+
+Check that the C<binlog_format> is the same on all servers.
+
+See "Replicas using row-based replication" under L<"LIMITATIONS">.
+
 =item --[no]check-plan
 
 default: yes
@@ -11322,7 +11350,12 @@ pt-table-checksum requires statement-based replication, and it sets
 C<binlog_format=STATEMENT> on the master, but due to a MySQL limitation
 replicas do not honor this change.  Therefore, checksums will not replicate
 past any replicas using row-based replication that are masters for
-further replicas.  (L<Bug 899415|https://bugs.launchpad.net/percona-toolkit/+bug/899415>)
+further replicas.
+
+The tool automatically checks the C<binlog_format> on all servers.
+See L<"--[no]check-binlog-format"> 
+
+(L<Bug 899415|https://bugs.launchpad.net/percona-toolkit/+bug/899415>)
 
 =item Percona XtraDB Cluster