Merge branch '5.5' into 10.1

20 files changed, 372 insertions, 121 deletions

diff --git a/client/mysqldump.c b/client/mysqldump.c
index 624096189b7..5edb0793642 100644
--- a/client/mysqldump.c
+++ b/client/mysqldump.c
@@ -32,7 +32,7 @@
 ** master/autocommit code by Brian Aker <brian@tangent.org>
 ** SSL by
 ** Andrei Errapart <andreie@no.spam.ee>
-** Tõnu Samuel  <tonu@please.do.not.remove.this.spam.ee>
+** Tõnu Samuel  <tonu@please.do.not.remove.this.spam.ee>
 ** XML by Gary Huntress <ghuntress@mediaone.net> 10/10/01, cleaned up
 ** and adapted to mysqldump 05/11/01 by Jani Tolonen
 ** Added --single-transaction option 06/06/2002 by Peter Zaitsev
diff --git a/include/queues.h b/include/queues.h
index f341bbb8148..99e640413e3 100644
--- a/include/queues.h
+++ b/include/queues.h
@@ -55,7 +55,7 @@ typedef struct st_queue {
 #define queue_top(queue) ((queue)->root[1])
 #define queue_element(queue,index) ((queue)->root[index])
 #define queue_end(queue) ((queue)->root[(queue)->elements])
-#define queue_replace_top(queue) _downheap(queue, 1, (queue)->root[1])
+#define queue_replace_top(queue) _downheap(queue, 1)
 #define queue_set_cmp_arg(queue, set_arg) (queue)->first_cmp_arg= set_arg
 #define queue_set_max_at_top(queue, set_arg) \
   (queue)->max_at_top= set_arg ? -1 : 1
@@ -63,23 +63,23 @@ typedef struct st_queue {
 typedef int (*queue_compare)(void *,uchar *, uchar *);
 
 int init_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
-	       pbool max_at_top, queue_compare compare,
+	       my_bool max_at_top, queue_compare compare,
 	       void *first_cmp_arg, uint offset_to_queue_pos,
                uint auto_extent);
 int reinit_queue(QUEUE *queue,uint max_elements,uint offset_to_key,
-                 pbool max_at_top, queue_compare compare,
+                 my_bool max_at_top, queue_compare compare,
                  void *first_cmp_arg, uint offset_to_queue_pos,
                  uint auto_extent);
 int resize_queue(QUEUE *queue, uint max_elements);
 void delete_queue(QUEUE *queue);
-void queue_insert(QUEUE *queue,uchar *element);
+void queue_insert(QUEUE *queue, uchar *element);
 int queue_insert_safe(QUEUE *queue, uchar *element);
 uchar *queue_remove(QUEUE *queue,uint idx);
 void queue_replace(QUEUE *queue,uint idx);
 
 #define queue_remove_all(queue) { (queue)->elements= 0; }
 #define queue_is_full(queue) (queue->elements == queue->max_elements)
-void _downheap(QUEUE *queue, uint idx, uchar *element);
+void _downheap(QUEUE *queue, uint idx);
 void queue_fix(QUEUE *queue);
 #define is_queue_inited(queue) ((queue)->root != 0)
 
diff --git a/mysql-test/lib/My/SafeProcess/safe_process_win.cc b/mysql-test/lib/My/SafeProcess/safe_process_win.cc
index 7d81bf1a1b4..4dd4e24f30d 100644
--- a/mysql-test/lib/My/SafeProcess/safe_process_win.cc
+++ b/mysql-test/lib/My/SafeProcess/safe_process_win.cc
@@ -206,7 +206,7 @@ int main(int argc, const char** argv )
     } else {
       if (strcmp(arg, "--verbose") == 0)
         verbose++;
-      else if (strncmp(arg, "--parent-pid", 10) == 0)
+      else if (strncmp(arg, "--parent-pid", 12) == 0)
       {
             /* Override parent_pid with a value provided by user */
         const char* start;
diff --git a/mysql-test/mysql-test-run.pl b/mysql-test/mysql-test-run.pl
index 920d66987e3..43e35bdab6d 100755
--- a/mysql-test/mysql-test-run.pl
+++ b/mysql-test/mysql-test-run.pl
@@ -281,7 +281,7 @@ my $current_config_name; # The currently running config file template
 our @opt_experimentals;
 our $experimental_test_cases= [];
 
-my $baseport;
+our $baseport;
 # $opt_build_thread may later be set from $opt_port_base
 my $opt_build_thread= $ENV{'MTR_BUILD_THREAD'} || "auto";
 my $opt_port_base= $ENV{'MTR_PORT_BASE'} || "auto";
diff --git a/mysql-test/suite.pm b/mysql-test/suite.pm
index f90679e6f1f..3db419bae84 100644
--- a/mysql-test/suite.pm
+++ b/mysql-test/suite.pm
@@ -62,9 +62,10 @@ sub skip_combinations {
   sub ipv6_ok() {
     use Socket;
     return 0 unless socket my $sock, PF_INET6, SOCK_STREAM, getprotobyname('tcp');
+    $!="";
     # eval{}, if there's no Socket::sockaddr_in6 at all, old Perl installation
-    eval { connect $sock, sockaddr_in6(7, Socket::IN6ADDR_LOOPBACK) };
-    return $@ eq "";
+    eval { bind $sock, sockaddr_in6($::baseport, Socket::IN6ADDR_LOOPBACK) };
+    return $@ eq "" && $! eq ""
   }
   $skip{'include/check_ipv6.inc'} = 'No IPv6' unless ipv6_ok();
 
diff --git a/mysql-test/suite/rpl/r/rpl_conditional_comments.result b/mysql-test/suite/rpl/r/rpl_conditional_comments.result
index 5668322d4aa..f8ceed3fa36 100644
--- a/mysql-test/suite/rpl/r/rpl_conditional_comments.result
+++ b/mysql-test/suite/rpl/r/rpl_conditional_comments.result
@@ -65,5 +65,20 @@ include/diff_tables.inc [master:t1,slave:t1]
 # comments
 SELECT c1 FROM /*!999999 t1 WHEREN;
 ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '/*!999999 t1 WHEREN' at line 1
+insert t1 values (/*!50505 1 /* foo */ */ + 2);
+insert t1 values (/*!999999 10 /* foo */ */ + 20);
+include/show_binlog_events.inc
+Log_name	Pos	Event_type	Server_id	End_log_pos	Info
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; insert t1 values (/*!50505 1 /* foo */ */ + 2)
+master-bin.000001	#	Query	#	#	COMMIT
+master-bin.000001	#	Gtid	#	#	BEGIN GTID #-#-#
+master-bin.000001	#	Query	#	#	use `test`; insert t1 values (/* 999999 10 (* foo *) */ + 20)
+master-bin.000001	#	Query	#	#	COMMIT
+select * from t1;
+c1
+62
+3
+20
 DROP TABLE t1;
 include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/r/rpl_fail_register.result b/mysql-test/suite/rpl/r/rpl_fail_register.result
new file mode 100644
index 00000000000..4e433636ad9
--- /dev/null
+++ b/mysql-test/suite/rpl/r/rpl_fail_register.result
@@ -0,0 +1,16 @@
+include/master-slave.inc
+[connection master]
+set @old_dbug=@@global.debug_dbug;
+set global debug_dbug='d,fail_com_register_slave';
+stop slave;
+reset slave;
+include/wait_for_slave_to_stop.inc
+start slave;
+stop slave;
+include/wait_for_slave_to_stop.inc
+set global debug_dbug=@old_dbug;
+kill DUMP_THREAD;
+show slave hosts;
+Server_id	Host	Port	Master_id
+start slave;
+include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_conditional_comments.test b/mysql-test/suite/rpl/t/rpl_conditional_comments.test
index bcc964a92c7..6e4ec8745f4 100644
--- a/mysql-test/suite/rpl/t/rpl_conditional_comments.test
+++ b/mysql-test/suite/rpl/t/rpl_conditional_comments.test
@@ -68,7 +68,17 @@ sync_slave_with_master;
 --echo # comments
 --connection master
 --error 1064
-SELECT c1 FROM /*!999999 t1 WHEREN;
+SELECT c1 FROM /*!999999 t1 WHEREN; #*/
+
+#
+# Bug#28388217 - SERVER CAN FAIL WHILE REPLICATING CONDITIONAL COMMENTS
+#
+insert t1 values (/*!50505 1 /* foo */ */ + 2);
+insert t1 values (/*!999999 10 /* foo */ */ + 20);
+source include/show_binlog_events.inc;
+sync_slave_with_master;
+select * from t1;
+connection master;
 
 DROP TABLE t1;
 --source include/rpl_end.inc
diff --git a/mysql-test/suite/rpl/t/rpl_fail_register.test b/mysql-test/suite/rpl/t/rpl_fail_register.test
new file mode 100644
index 00000000000..bfecc9d7f14
--- /dev/null
+++ b/mysql-test/suite/rpl/t/rpl_fail_register.test
@@ -0,0 +1,33 @@
+source include/have_debug.inc;
+source include/have_binlog_format_mixed.inc;
+source include/master-slave.inc;
+
+connection slave;
+
+set @old_dbug=@@global.debug_dbug;
+set global debug_dbug='d,fail_com_register_slave';
+
+stop slave;
+reset slave;
+source include/wait_for_slave_to_stop.inc;
+start slave;
+stop slave;
+source include/wait_for_slave_to_stop.inc;
+set global debug_dbug=@old_dbug;
+
+connection master;
+
+### why is that needed?
+let $id=`SELECT id from information_schema.processlist where command='Binlog Dump'`;
+if ($id) {
+  replace_result $id DUMP_THREAD;
+  eval kill $id;
+  let $wait_condition= SELECT count(*)=0 from information_schema.processlist where command='Binlog Dump';
+  source include/wait_condition.inc;
+}
+
+show slave hosts;
+
+connection slave;
+start slave;
+source include/rpl_end.inc;
diff --git a/mysys/queues.c b/mysys/queues.c
index 5d09ce2063f..7a0ef2017c2 100644
--- a/mysys/queues.c
+++ b/mysys/queues.c
@@ -70,10 +70,9 @@
 */
 
 int init_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
-	       pbool max_at_top, int (*compare) (void *, uchar *, uchar *),
+	       my_bool max_at_top, int (*compare) (void *, uchar *, uchar *),
 	       void *first_cmp_arg, uint offset_to_queue_pos,
                uint auto_extent)
-               
 {
   DBUG_ENTER("init_queue");
   if ((queue->root= (uchar **) my_malloc((max_elements + 1) * sizeof(void*),
@@ -109,7 +108,7 @@ int init_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
 */
 
 int reinit_queue(QUEUE *queue, uint max_elements, uint offset_to_key,
-		 pbool max_at_top, int (*compare) (void *, uchar *, uchar *),
+		 my_bool max_at_top, int (*compare) (void *, uchar *, uchar *),
 		 void *first_cmp_arg, uint offset_to_queue_pos,
                  uint auto_extent)
 {
@@ -182,6 +181,28 @@ void delete_queue(QUEUE *queue)
 }
 
 
+static void insert_at(QUEUE *queue, uchar *element, uint idx)
+{
+  uint next_index, offset_to_key= queue->offset_to_key;
+  uint offset_to_queue_pos= queue->offset_to_queue_pos;
+  /* max_at_top swaps the comparison if we want to order by desc */
+  while ((next_index= idx >> 1) > 0 &&
+          queue->compare(queue->first_cmp_arg,
+                         element + offset_to_key,
+                         queue->root[next_index] + offset_to_key) *
+          queue->max_at_top < 0)
+  {
+    queue->root[idx]= queue->root[next_index];
+    if (offset_to_queue_pos)
+      (*(uint*) (queue->root[idx] + offset_to_queue_pos-1))= idx;
+    idx= next_index;
+  }
+  queue->root[idx]= element;
+  if (offset_to_queue_pos)
+    (*(uint*) (element + offset_to_queue_pos-1))= idx;
+}
+
+
 /*
   Insert element in queue
 
@@ -191,28 +212,10 @@ void delete_queue(QUEUE *queue)
     element		Element to insert
 */
 
-void queue_insert(register QUEUE *queue, uchar *element)
+void queue_insert(QUEUE *queue, uchar *element)
 {
-  reg2 uint idx, next;
-  uint offset_to_queue_pos= queue->offset_to_queue_pos;
   DBUG_ASSERT(queue->elements < queue->max_elements);
-
-  idx= ++queue->elements;
-  /* max_at_top swaps the comparison if we want to order by desc */
-  while (idx > 1 &&
-         (queue->compare(queue->first_cmp_arg,
-                         element + queue->offset_to_key,
-                         queue->root[(next= idx >> 1)] +
-                         queue->offset_to_key) * queue->max_at_top) < 0)
-  {
-    queue->root[idx]= queue->root[next];
-    if (offset_to_queue_pos)
-      (*(uint*) (queue->root[idx] + offset_to_queue_pos-1))= idx;
-    idx= next;
-  }
-  queue->root[idx]= element;
-  if (offset_to_queue_pos)
-    (*(uint*) (element+ offset_to_queue_pos-1))= idx;
+  insert_at(queue, element, ++queue->elements);
 }
 
 
@@ -230,7 +233,7 @@ void queue_insert(register QUEUE *queue, uchar *element)
     2   auto_extend is 0; No insertion done
 */
 
-int queue_insert_safe(register QUEUE *queue, uchar *element)
+int queue_insert_safe(QUEUE *queue, uchar *element)
 {
 
   if (queue->elements == queue->max_elements)
@@ -240,7 +243,7 @@ int queue_insert_safe(register QUEUE *queue, uchar *element)
     if (resize_queue(queue, queue->max_elements + queue->auto_extent))
       return 1;
   }
-  
+
   queue_insert(queue, element);
   return 0;
 }
@@ -259,81 +262,55 @@ int queue_insert_safe(register QUEUE *queue, uchar *element)
    pointer to removed element
 */
 
-uchar *queue_remove(register QUEUE *queue, uint idx)
+uchar *queue_remove(QUEUE *queue, uint idx)
 {
   uchar *element;
-  DBUG_ASSERT(idx >= 1 && idx <= queue->elements);
+  DBUG_ASSERT(idx >= 1);
+  DBUG_ASSERT(idx <= queue->elements);
   element= queue->root[idx];
-  _downheap(queue, idx, queue->root[queue->elements--]);
+  queue->root[idx]= queue->root[queue->elements--];
+  queue_replace(queue, idx);
   return element;
 }
 
 
 /*
-  Add element to fixed position and update heap
+  Restores the heap property from idx down the heap
 
   SYNOPSIS
     _downheap()
     queue	Queue to use
     idx         Index of element to change
-    element     Element to store at 'idx'
-
-  NOTE
-    This only works if element is >= all elements <= start_idx
 */
 
-void _downheap(register QUEUE *queue, uint start_idx, uchar *element)
+void _downheap(QUEUE *queue, uint idx)
 {
-  uint elements,half_queue,offset_to_key, next_index, offset_to_queue_pos;
-  register uint idx= start_idx;
-  my_bool first= TRUE;
-
-  offset_to_key=queue->offset_to_key;
-  offset_to_queue_pos= queue->offset_to_queue_pos;
-  half_queue= (elements= queue->elements) >> 1;
+  uchar *element= queue->root[idx];
+  uint   next_index,
+         elements= queue->elements,
+         half_queue= elements >> 1,
+         offset_to_key= queue->offset_to_key,
+         offset_to_queue_pos= queue->offset_to_queue_pos;
 
   while (idx <= half_queue)
   {
-    next_index=idx+idx;
+    next_index= idx+idx;
     if (next_index < elements &&
-	(queue->compare(queue->first_cmp_arg,
-			queue->root[next_index]+offset_to_key,
-			queue->root[next_index+1]+offset_to_key) *
-	 queue->max_at_top) > 0)
+        (queue->compare(queue->first_cmp_arg,
+                        queue->root[next_index]+offset_to_key,
+                        queue->root[next_index+1]+offset_to_key) *
+         queue->max_at_top) > 0)
       next_index++;
-    if (first && 
-        (((queue->compare(queue->first_cmp_arg,
-                          queue->root[next_index]+offset_to_key,
-                          element+offset_to_key) * queue->max_at_top) >= 0)))
-    {
-      queue->root[idx]= element;
-      if (offset_to_queue_pos)
-        (*(uint*) (element + offset_to_queue_pos-1))= idx;
-      return;
-    }
-    first= FALSE;
-    queue->root[idx]= queue->root[next_index];
-    if (offset_to_queue_pos)
-      (*(uint*) (queue->root[idx] + offset_to_queue_pos-1))= idx;
-    idx=next_index;
-  }
-
-  /*
-    Insert the element into the right position. This is the same code
-    as we have in queue_insert()
-  */
-  while ((next_index= (idx >> 1)) > start_idx &&
-         queue->compare(queue->first_cmp_arg,
-                        element+offset_to_key,
-                        queue->root[next_index]+offset_to_key)*
-         queue->max_at_top < 0)
-  {
+    if ((queue->compare(queue->first_cmp_arg,
+                        queue->root[next_index]+offset_to_key,
+                        element+offset_to_key) * queue->max_at_top) >= 0)
+      break;
     queue->root[idx]= queue->root[next_index];
     if (offset_to_queue_pos)
       (*(uint*) (queue->root[idx] + offset_to_queue_pos-1))= idx;
     idx= next_index;
   }
-  queue->root[idx]= element;
+  queue->root[idx]=element;
   if (offset_to_queue_pos)
     (*(uint*) (element + offset_to_queue_pos-1))= idx;
 }
@@ -351,7 +328,7 @@ void queue_fix(QUEUE *queue)
 {
   uint i;
   for (i= queue->elements >> 1; i > 0; i--)
-    _downheap(queue, i, queue_element(queue, i));
+    _downheap(queue, i);
 }
 
 
@@ -362,13 +339,47 @@ void queue_fix(QUEUE *queue)
     queue_replace()
     queue	Queue to use
     idx         Index of element to change
-    element     Element to store at 'idx'
+
+  NOTE
+    optimized for the case when the new position is close to the end of the
+    heap (typical for queue_remove() replacements).
 */
 
 void queue_replace(QUEUE *queue, uint idx)
 {
   uchar *element= queue->root[idx];
-  DBUG_ASSERT(idx >= 1 && idx <= queue->elements);
-  queue_remove(queue, idx);
-  queue_insert(queue, element);
+  uint next_index,
+       elements= queue->elements,
+       half_queue= elements>>1,
+       offset_to_key= queue->offset_to_key,
+       offset_to_queue_pos= queue->offset_to_queue_pos;
+  my_bool first= TRUE;
+
+  while (idx <= half_queue)
+  {
+    next_index= idx + idx;
+    if (next_index < elements &&
+	queue->compare(queue->first_cmp_arg,
+			queue->root[next_index]+offset_to_key,
+			queue->root[next_index+1]+offset_to_key) *
+	 queue->max_at_top > 0)
+      next_index++;
+    if (first &&
+        queue->compare(queue->first_cmp_arg,
+                        queue->root[next_index]+offset_to_key,
+                        element+offset_to_key) * queue->max_at_top >= 0)
+    {
+      queue->root[idx]= element;
+      if (offset_to_queue_pos)
+        (*(uint*) (element + offset_to_queue_pos-1))= idx;
+      break;
+    }
+    first= FALSE;
+    queue->root[idx]= queue->root[next_index];
+    if (offset_to_queue_pos)
+      (*(uint*) (queue->root[idx] + offset_to_queue_pos-1))= idx;
+    idx=next_index;
+  }
+
+  insert_at(queue, element, idx);
 }
diff --git a/sql-common/client.c b/sql-common/client.c
index 4f1cc6c564e..eee0ba8f2dd 100644
--- a/sql-common/client.c
+++ b/sql-common/client.c
@@ -1403,9 +1403,23 @@ unpack_fields(MYSQL *mysql, MYSQL_DATA *data,MEM_ROOT *alloc,uint fields,
     {
       if (field - result >= (my_ptrdiff_t)fields)
         goto err;
+
+      /*
+       If any of the row->data[] below is NULL, it can result in a
+       crash. Error out early as it indicates a malformed packet.
+       For data[0], data[1] and data[5], strmake_root will handle
+       NULL values.
+      */
+      if (!row->data[2] || !row->data[3] || !row->data[4])
+      {
+        free_rows(data);
+        set_mysql_error(mysql, CR_MALFORMED_PACKET, unknown_sqlstate);
+        DBUG_RETURN(0);
+      }
+
       cli_fetch_lengths(&lengths[0], row->data, default_value ? 6 : 5);
-      field->org_table= field->table=  strdup_root(alloc,(char*) row->data[0]);
-      field->name=   strdup_root(alloc,(char*) row->data[1]);
+      field->org_table= field->table=  strmake_root(alloc,(char*) row->data[0], lengths[0]);
+      field->name=   strmake_root(alloc,(char*) row->data[1], lengths[1]);
       field->length= (uint) uint3korr(row->data[2]);
       field->type=   (enum enum_field_types) (uchar) row->data[3][0];
 
@@ -1430,7 +1444,7 @@ unpack_fields(MYSQL *mysql, MYSQL_DATA *data,MEM_ROOT *alloc,uint fields,
         field->flags|= NUM_FLAG;
       if (default_value && row->data[5])
       {
-        field->def=strdup_root(alloc,(char*) row->data[5]);
+        field->def= strmake_root(alloc,(char*) row->data[5], lengths[5]);
 	field->def_length= lengths[5];
       }
       else
diff --git a/sql/event_scheduler.cc b/sql/event_scheduler.cc
index 8c49e6f2746..96ea298fd11 100644
--- a/sql/event_scheduler.cc
+++ b/sql/event_scheduler.cc
@@ -1,4 +1,5 @@
-/* Copyright (c) 2006, 2013, Oracle and/or its affiliates.
+/* Copyright (c) 2006, 2019, Oracle and/or its affiliates.
+   Copyright (c) 2009, 2020, MariaDB Corporation
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -507,6 +508,7 @@ Event_scheduler::run(THD *thd)
       DBUG_PRINT("info", ("job_data is NULL, the thread was killed"));
     }
     DBUG_PRINT("info", ("state=%s", scheduler_states_names[state].str));
+    free_root(thd->mem_root, MYF(0));
   }
 
   LOCK_DATA();
diff --git a/sql/opt_range.cc b/sql/opt_range.cc
index 92268ba69aa..e0eefe167ce 100644
--- a/sql/opt_range.cc
+++ b/sql/opt_range.cc
@@ -358,9 +358,8 @@ QUICK_RANGE_SELECT *get_quick_select(PARAM *param,uint index,
                                      uint mrr_buf_size, MEM_ROOT *alloc);
 static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
                                        bool index_read_must_be_used,
-                                       bool update_tbl_stats,
-                                       double read_time,
-                                       bool ror_scans_required);
+                                       bool for_range_access,
+                                       double read_time);
 static
 TRP_INDEX_INTERSECT *get_best_index_intersect(PARAM *param, SEL_TREE *tree,
                                               double read_time);
@@ -2599,7 +2598,7 @@ int SQL_SELECT::test_quick_select(THD *thd, key_map keys_to_use,
 
       /* Get best 'range' plan and prepare data for making other plans */
       if ((range_trp= get_key_scans_params(&param, tree, FALSE, TRUE,
-                                           best_read_time, FALSE)))
+                                           best_read_time)))
       {
         best_trp= range_trp;
         best_read_time= best_trp->read_cost;
@@ -4686,7 +4685,6 @@ TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge,
   double roru_index_costs;
   ha_rows roru_total_records;
   double roru_intersect_part= 1.0;
-  bool only_ror_scans_required= FALSE;
   DBUG_ENTER("get_best_disjunct_quick");
   DBUG_PRINT("info", ("Full table scan cost: %g", read_time));
 
@@ -4713,8 +4711,6 @@ TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge,
                                              n_child_scans)))
     DBUG_RETURN(NULL);
 
-  only_ror_scans_required= !optimizer_flag(param->thd,
-                                      OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION);
   /*
     Collect best 'range' scan for each of disjuncts, and, while doing so,
     analyze possibility of ROR scans. Also calculate some values needed by
@@ -4727,8 +4723,7 @@ TABLE_READ_PLAN *get_best_disjunct_quick(PARAM *param, SEL_IMERGE *imerge,
     DBUG_EXECUTE("info", print_sel_tree(param, *ptree, &(*ptree)->keys_map,
                                         "tree in SEL_IMERGE"););
     if (!(*cur_child= get_key_scans_params(param, *ptree, TRUE, FALSE,
-                                           read_time,
-                                           only_ror_scans_required)))
+                                           read_time)))
     {
       /*
         One of index scans in this index_merge is more expensive than entire
@@ -5048,9 +5043,12 @@ TABLE_READ_PLAN *merge_same_index_scans(PARAM *param, SEL_IMERGE *imerge,
          a random order
       2. the functions that estimate the cost of a range scan and an
          index merge retrievals are not well calibrated
+
+      As the best range access has been already chosen it does not
+      make sense to evaluate the one obtained from a degenerated
+      index merge.
     */
-    trp= get_key_scans_params(param, *imerge->trees, FALSE, TRUE,
-                              read_time, FALSE);
+    trp= 0;
   }
 
   DBUG_RETURN(trp); 
@@ -6777,9 +6775,9 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
       tree         make range select for this SEL_TREE
       index_read_must_be_used if TRUE, assume 'index only' option will be set
                              (except for clustered PK indexes)
+      for_range_access     if TRUE the function is called to get the best range
+                           plan for range access, not for index merge access
       read_time    don't create read plans with cost > read_time.
-      only_ror_scans_required         set to TRUE when we are only interested
-                                      in ROR scan
   RETURN
     Best range read plan
     NULL if no plan found or error occurred
@@ -6787,9 +6785,8 @@ TRP_ROR_INTERSECT *get_best_covering_ror_intersect(PARAM *param,
 
 static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
                                        bool index_read_must_be_used, 
-                                       bool update_tbl_stats,
-                                       double read_time,
-                                       bool only_ror_scans_required)
+                                       bool for_range_access,
+                                       double read_time)
 {
   uint idx, best_idx;
   SEL_ARG *key_to_read= NULL;
@@ -6834,10 +6831,11 @@ static TRP_RANGE *get_key_scans_params(PARAM *param, SEL_TREE *tree,
                             (bool) param->table->covering_keys.is_set(keynr);
 
       found_records= check_quick_select(param, idx, read_index_only, key,
-                                        update_tbl_stats, &mrr_flags,
+                                        for_range_access, &mrr_flags,
                                         &buf_size, &cost);
 
-      if (only_ror_scans_required && !param->is_ror_scan)
+      if (!for_range_access && !param->is_ror_scan &&
+          !optimizer_flag(param->thd,OPTIMIZER_SWITCH_INDEX_MERGE_SORT_UNION))
       {
         /* The scan is not a ROR-scan, just skip it */
         continue;
diff --git a/sql/slave.cc b/sql/slave.cc
index 26fabc2cc52..0ce9c4cbbcd 100644
--- a/sql/slave.cc
+++ b/sql/slave.cc
@@ -4304,6 +4304,7 @@ connected:
         goto err;
       goto connected;
     }
+    DBUG_EXECUTE_IF("fail_com_register_slave", goto err;);
   }
 
   DBUG_PRINT("info",("Starting reading binary log from master"));
diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index ab105c67507..6897a26bda1 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -71,6 +71,7 @@
 #ifdef HAVE_SYS_SYSCALL_H
 #include <sys/syscall.h>
 #endif
+#include "repl_failsafe.h"
 
 /*
   The following is used to initialise Table_ident with a internal
@@ -1593,6 +1594,7 @@ THD::~THD()
   if (rgi_slave)
     rgi_slave->cleanup_after_session();
   my_free(semisync_info);
+  unregister_slave(this, true, true);
 #endif
   main_lex.free_set_stmt_mem_root();
   free_root(&main_mem_root, MYF(0));
diff --git a/sql/sql_lex.cc b/sql/sql_lex.cc
index 27da1fc16fd..02c0df97cf3 100644
--- a/sql/sql_lex.cc
+++ b/sql/sql_lex.cc
@@ -1,5 +1,5 @@
-/* Copyright (c) 2000, 2014, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2018, MariaDB Corporation
+/* Copyright (c) 2000, 2019, Oracle and/or its affiliates.
+   Copyright (c) 2009, 2020, MariaDB Corporation
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -1181,17 +1181,27 @@ static inline uint int_token(const char *str,uint length)
 */
 bool consume_comment(Lex_input_stream *lip, int remaining_recursions_permitted)
 {
+  // only one level of nested comments are allowed
+  DBUG_ASSERT(remaining_recursions_permitted == 0 ||
+              remaining_recursions_permitted == 1);
   uchar c;
   while (! lip->eof())
   {
     c= lip->yyGet();
 
-    if (remaining_recursions_permitted > 0)
+    if (remaining_recursions_permitted == 1)
     {
       if ((c == '/') && (lip->yyPeek() == '*'))
       {
+        lip->yyUnput('(');  // Replace nested "/*..." with "(*..."
+        lip->yySkip();      // and skip "("
+
         lip->yySkip(); /* Eat asterisk */
-        consume_comment(lip, remaining_recursions_permitted-1);
+        if (consume_comment(lip, 0))
+          return true;
+
+        lip->yyUnput(')');  // Replace "...*/" with "...*)"
+        lip->yySkip();      // and skip ")"
         continue;
       }
     }
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index d19cbf5ad9b..656da3b6a79 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -1739,7 +1739,6 @@ bool dispatch_command(enum enum_server_command command, THD *thd,
       general_log_print(thd, command, "Log: '%s'  Pos: %lu", name, pos);
       if (nlen < FN_REFLEN)
         mysql_binlog_send(thd, thd->strmake(name, nlen), (my_off_t)pos, flags);
-      unregister_slave(thd,1,1);
       /*  fake COM_QUIT -- if we get here, the thread needs to terminate */
       error = TRUE;
       break;
diff --git a/storage/tokudb/PerconaFT/cmake_modules/TokuSetupCompiler.cmake b/storage/tokudb/PerconaFT/cmake_modules/TokuSetupCompiler.cmake
index 8f65895cc9c..8b3a0e61418 100644
--- a/storage/tokudb/PerconaFT/cmake_modules/TokuSetupCompiler.cmake
+++ b/storage/tokudb/PerconaFT/cmake_modules/TokuSetupCompiler.cmake
@@ -170,9 +170,9 @@ if (NOT CMAKE_CXX_COMPILER_ID STREQUAL Clang)
   set_cflags_if_supported(-Wcast-align)
 endif ()
 
-## always want these in debug builds
-set(CMAKE_C_FLAGS_DEBUG "-Wall -Werror ${CMAKE_C_FLAGS_DEBUG}")
-set(CMAKE_CXX_FLAGS_DEBUG "-Wall -Werror ${CMAKE_CXX_FLAGS_DEBUG}")
+## never want these
+set(CMAKE_C_FLAGS "-Wno-error ${CMAKE_C_FLAGS}")
+set(CMAKE_CXX_FLAGS "-Wno-error ${CMAKE_CXX_FLAGS}")
 
 # pick language dialect
 set(CMAKE_C_FLAGS "-std=c99 ${CMAKE_C_FLAGS}")
diff --git a/unittest/mysys/CMakeLists.txt b/unittest/mysys/CMakeLists.txt
index dd0db94a77c..9ad7e76f547 100644
--- a/unittest/mysys/CMakeLists.txt
+++ b/unittest/mysys/CMakeLists.txt
@@ -15,7 +15,7 @@
 
 MY_ADD_TESTS(bitmap base64 my_atomic my_rdtsc lf my_malloc my_getopt dynstring
              aes
-             LINK_LIBRARIES mysys)
+             queues LINK_LIBRARIES mysys)
 MY_ADD_TESTS(my_vsnprintf LINK_LIBRARIES strings mysys)
 
 ADD_DEFINITIONS(${SSL_DEFINES})
diff --git a/unittest/mysys/queues-t.c b/unittest/mysys/queues-t.c
new file mode 100644
index 00000000000..23cb0da1a32
--- /dev/null
+++ b/unittest/mysys/queues-t.c
@@ -0,0 +1,139 @@
+/* Copyright (c) 2020, MariaDB Corporation
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; version 2 of the License.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA */
+
+#include <my_global.h>
+#include <my_sys.h>
+#include <queues.h>
+#include <my_rnd.h>
+#include "tap.h"
+
+int cmp(void *arg __attribute__((unused)), uchar *a, uchar *b)
+{
+  return *a < *b ? -1 : *a > *b;
+}
+
+#define rnd(R) ((uint)(my_rnd(R) * INT_MAX32))
+
+#define el(Q,I) ((uint)*queue_element(Q, I))
+
+my_bool verbose;
+
+my_bool check_queue(QUEUE *queue)
+{
+  char b[1024]={0}, *s, *e=b+sizeof(b)-2;
+  my_bool ok=1;
+  uint i;
+
+  s= b + my_snprintf(b, e-b, "%x", el(queue, 1));
+  for (i=2; i <= queue->elements; i++)
+  {
+    s+= my_snprintf(s, e-s, ", %x", el(queue, i));
+    ok &= el(queue, i) <= el(queue, i>>1);
+  }
+  if (!ok || verbose)
+    diag("%s", b);
+  return ok;
+}
+
+int main(int argc __attribute__((unused)), char *argv[])
+{
+  QUEUE q, *queue=&q;
+  MY_INIT(argv[0]);
+  plan(19);
+
+  verbose=1;
+
+  init_queue(queue, 256, 0, 1, cmp, NULL, 0, 0);
+  queue_insert(queue, (uchar*)"\x99");
+  queue_insert(queue, (uchar*)"\x19");
+  queue_insert(queue, (uchar*)"\x36");
+  queue_insert(queue, (uchar*)"\x17");
+  queue_insert(queue, (uchar*)"\x12");
+  queue_insert(queue, (uchar*)"\x05");
+  queue_insert(queue, (uchar*)"\x25");
+  queue_insert(queue, (uchar*)"\x09");
+  queue_insert(queue, (uchar*)"\x15");
+  queue_insert(queue, (uchar*)"\x06");
+  queue_insert(queue, (uchar*)"\x11");
+  queue_insert(queue, (uchar*)"\x01");
+  queue_insert(queue, (uchar*)"\x04");
+  queue_insert(queue, (uchar*)"\x13");
+  queue_insert(queue, (uchar*)"\x24");
+  ok(check_queue(queue), "after insert");
+  queue_remove(queue, 5);
+  ok(check_queue(queue), "after remove 5th");
+
+  queue_element(queue, 1) = (uchar*)"\x01";
+  queue_element(queue, 2) = (uchar*)"\x10";
+  queue_element(queue, 3) = (uchar*)"\x04";
+  queue_element(queue, 4) = (uchar*)"\x09";
+  queue_element(queue, 5) = (uchar*)"\x13";
+  queue_element(queue, 6) = (uchar*)"\x03";
+  queue_element(queue, 7) = (uchar*)"\x08";
+  queue_element(queue, 8) = (uchar*)"\x07";
+  queue_element(queue, 9) = (uchar*)"\x06";
+  queue_element(queue,10) = (uchar*)"\x12";
+  queue_element(queue,11) = (uchar*)"\x05";
+  queue_element(queue,12) = (uchar*)"\x02";
+  queue_element(queue,13) = (uchar*)"\x11";
+  queue->elements= 13;
+  ok(!check_queue(queue), "manually filled (queue property violated)");
+
+  queue_fix(queue);
+  ok(check_queue(queue), "fixed");
+
+  ok(*queue_remove_top(queue) == 0x13, "remove top 13");
+  ok(*queue_remove_top(queue) == 0x12, "remove top 12");
+  ok(*queue_remove_top(queue) == 0x11, "remove top 11");
+  ok(*queue_remove_top(queue) == 0x10, "remove top 10");
+  ok(*queue_remove_top(queue) == 0x09, "remove top 9");
+  ok(*queue_remove_top(queue) == 0x08, "remove top 8");
+  ok(*queue_remove_top(queue) == 0x07, "remove top 7");
+  ok(*queue_remove_top(queue) == 0x06, "remove top 6");
+  ok(*queue_remove_top(queue) == 0x05, "remove top 5");
+  ok(*queue_remove_top(queue) == 0x04, "remove top 4");
+  ok(*queue_remove_top(queue) == 0x03, "remove top 3");
+  ok(*queue_remove_top(queue) == 0x02, "remove top 2");
+  ok(*queue_remove_top(queue) == 0x01, "remove top 1");
+
+  /* random test */
+  {
+    int i, res;
+    struct my_rnd_struct rand;
+    my_rnd_init(&rand, (ulong)(intptr)&i, (ulong)(intptr)argv);
+    verbose=0;
+
+    for (res= i=1; i <= 250; i++)
+    {
+      uchar *s=alloca(2);
+      *s= rnd(&rand) % 251;
+      queue_insert(queue, s);
+      res &= check_queue(queue);
+    }
+    ok(res, "inserted 250");
+
+    while (queue->elements)
+    {
+      queue_remove(queue, (rnd(&rand) % queue->elements) + 1);
+      res &= check_queue(queue);
+    }
+    ok(res, "removed 250");
+  }
+
+  delete_queue(queue);
+  my_end(0);
+  return exit_status();
+}
+