PT-1852 Added --no-check-foreing-keys to pt-osc

bin/pt-online-schema-change

@@ -9102,6 +9102,15 @@ sub main {
                $child_table->{name},
                $child_table->{row_est} || '?';
          }
+         
+         # TODO: Fix self referencing foreign keys handling.
+         # See: https://jira.percona.com/browse/PT-1802
+         #      https://jira.percona.com/browse/PT-1853
+         if (has_self_ref_fks($orig_tbl->{db}, $orig_tbl->{tbl}, $child_tables) and $o->get('check-foreign-keys')) {
+             print "The table has self referencing foreign keys and that might lead to errors.\n";
+             print "Use --no-check-foreign-keys to disable this check.\n";
+             return 1
+         }
 
          if ( $alter_fk_method ) {
             # Let the user know how we're going to update the child table
@@ -10396,6 +10405,20 @@ sub check_alter {
    return;
 }
 
+sub has_self_ref_fks { 
+    my ($orig_db, $orig_table, $child_tables) = @_;
+
+    my $db_tbl = sprintf("`%s`.`%s`", $orig_db, $orig_table);
+
+    foreach my $child_table ( @$child_tables ) {
+        if ($db_tbl eq $child_table->{name}) {
+             return 1;
+         }
+    };
+
+    return undef;
+}
+
 # This function tries to detect if the --alter param is adding unique indexes.
 # It returns an array of arrays, having a list of fields for each unique index
 # found. 
@@ -12168,6 +12191,15 @@ L<"--print"> and verify that the triggers are correct.
 
 =back
 
+=item --[no]check-foreign-keys
+
+default: yes
+
+Check for self referencing foreing keys. Currently self referencing FKs are
+not fully supported so to prevent errors, this program wont't run if the table
+has self referen foreign keys. Use this parameter to disable self referencing
+FK checks.
+
 =item --check-interval
 
 type: time; default: 1

t/pt-online-schema-change/pt-1853.t

@@ -0,0 +1,80 @@
+#!/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 threads;
+use threads::shared;
+use Thread::Semaphore;
+
+use English qw(-no_match_vars);
+use Test::More;
+
+use Data::Dumper;
+use PerconaTest;
+use Sandbox;
+use SqlModes;
+use File::Temp qw/ tempdir /;
+
+require "$trunk/bin/pt-online-schema-change";
+
+plan tests => 3;
+
+my $dp = new DSNParser(opts=>$dsn_opts);
+my $sb = new Sandbox(basedir => '/tmp', DSNParser => $dp);
+my $master_dbh = $sb->get_dbh_for("master");
+my $master_dsn = $sb->dsn_for("master");
+
+# The sandbox servers run with lock_wait_timeout=3 and it's not dynamic
+# so we need to specify --set-vars innodb_lock_wait_timeout=3 else the
+# tool will die.
+my @args = (qw(--set-vars innodb_lock_wait_timeout=3));
+my $output;
+my $exit_status;
+
+$sb->load_file('master', "t/pt-online-schema-change/samples/pt-1853.sql");
+
+($output, $exit_status) = full_output(
+    sub { pt_online_schema_change::main(@args, "$master_dsn,D=test,t=jointit",
+            '--execute', 
+            '--alter', "engine=innodb",
+            '--alter-foreign-keys-method', 'rebuild_constraints'
+        ),
+    },
+    stderr => 1,
+);
+
+isnt(
+    $exit_status,
+    0,
+    "PT-1853, there are self referencing FKs -> exit status != 0",
+);
+
+($output, $exit_status) = full_output(
+    sub { pt_online_schema_change::main(@args, "$master_dsn,D=test,t=jointit",
+            '--execute', 
+            '--alter', "engine=innodb",
+            '--alter-foreign-keys-method', 'rebuild_constraints',
+            '--no-check-foreign-keys'
+        ),
+    },
+    stderr => 1,
+);
+
+isnt(
+    $exit_status,
+    0,
+    "PT-1853, there are self referencing FKs but --no-check-foreign-keys was specifid -> exit status = 0",
+);
+
+# #############################################################################
+# Done.
+# #############################################################################
+$sb->wipe_clean($master_dbh);
+ok($sb->ok(), "Sandbox servers") or BAIL_OUT(__FILE__ . " broke the sandbox");
+done_testing;

t/pt-online-schema-change/samples/pt-1853.sql

@@ -0,0 +1,19 @@
+DROP DATABASE IF EXISTS test;
+CREATE DATABASE test;
+
+USE test;
+
+CREATE TABLE t1 (
+id int,
+f1 int
+);
+
+CREATE TABLE `joinit` (
+`i` int(11) NOT NULL AUTO_INCREMENT,
+`s` varchar(64) DEFAULT NULL,
+`t` time NOT NULL,
+`g` int(11) NOT NULL,
+`j` int(11) NOT NULL DEFAULT 1,
+PRIMARY KEY (`i`))
+ENGINE=InnoDB;
+ALTER TABLE joinit ADD FOREIGN KEY i_fk (j) REFERENCES joinit (i) ON UPDATE cascade ON DELETE restrict;