Merge 10.2 into 10.3

38 files changed, 417 insertions, 318 deletions

diff --git a/client/mysqltest.cc b/client/mysqltest.cc
index 316e52d95b4..425c5f98095 100644
--- a/client/mysqltest.cc
+++ b/client/mysqltest.cc
@@ -9091,10 +9091,6 @@ static void init_signal_handling(void)
   struct sigaction sa;
   DBUG_ENTER("init_signal_handling");
 
-#ifdef HAVE_STACKTRACE
-  my_init_stacktrace();
-#endif
-
   sa.sa_flags = SA_RESETHAND | SA_NODEFER;
   sigemptyset(&sa.sa_mask);
   sigprocmask(SIG_SETMASK, &sa.sa_mask, NULL);
diff --git a/extra/mariabackup/xtrabackup.cc b/extra/mariabackup/xtrabackup.cc
index 277e8b67cf0..0529cb18f23 100644
--- a/extra/mariabackup/xtrabackup.cc
+++ b/extra/mariabackup/xtrabackup.cc
@@ -249,6 +249,12 @@ my_bool innobase_locks_unsafe_for_binlog;
 my_bool innobase_rollback_on_timeout;
 my_bool innobase_create_status_file;
 
+/* The following counter is used to convey information to InnoDB
+about server activity: in selects it is not sensible to call
+srv_active_wake_master_thread after each fetch or search, we only do
+it every INNOBASE_WAKE_INTERVAL'th step. */
+
+#define INNOBASE_WAKE_INTERVAL	32
 ulong	innobase_active_counter	= 0;
 
 #ifndef _WIN32
@@ -2006,10 +2012,6 @@ static bool innodb_init_param()
 		srv_undo_dir = (char*) ".";
 	}
 
-	log_checksum_algorithm_ptr = innodb_log_checksums || srv_encrypt_log
-		? log_block_calc_checksum_crc32
-		: log_block_calc_checksum_none;
-
 #ifdef _WIN32
 	srv_use_native_aio = TRUE;
 #endif
diff --git a/include/my_stacktrace.h b/include/my_stacktrace.h
index 922a59c196a..015fa062752 100644
--- a/include/my_stacktrace.h
+++ b/include/my_stacktrace.h
@@ -41,7 +41,6 @@
 C_MODE_START
 
 #if defined(HAVE_STACKTRACE) || defined(HAVE_BACKTRACE)
-void my_init_stacktrace();
 void my_print_stacktrace(uchar* stack_bottom, ulong thread_stack,
                          my_bool silent);
 int my_safe_print_str(const char* val, size_t max_len);
@@ -52,8 +51,6 @@ char *my_demangle(const char *mangled_name, int *status);
 #ifdef __WIN__
 void my_set_exception_pointers(EXCEPTION_POINTERS *ep);
 #endif /* __WIN__ */
-#else
-#define my_init_stacktrace() do { } while(0)
 #endif /* ! (defined(HAVE_STACKTRACE) || defined(HAVE_BACKTRACE)) */
 
 #ifndef _WIN32
diff --git a/mysql-test/main/mysql_tzinfo_to_sql_symlink.result b/mysql-test/main/mysql_tzinfo_to_sql_symlink.result
index 06e21beace1..f56a2df2012 100644
--- a/mysql-test/main/mysql_tzinfo_to_sql_symlink.result
+++ b/mysql-test/main/mysql_tzinfo_to_sql_symlink.result
@@ -15,6 +15,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -32,6 +33,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/ignored.tab' as time zone. Skipping it.
 Warning: Skipping directory 'MYSQLTEST_VARDIR/zoneinfo/posix/posix': to avoid infinite symlink recursion.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 \d |
@@ -57,6 +59,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -71,6 +74,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
  (@time_zone_id, 0, 0, 0, 'GMT')
 ;
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 \d |
@@ -160,6 +164,8 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 \d |
diff --git a/mysql-test/suite/encryption/r/innodb_encrypt_log.result b/mysql-test/suite/encryption/r/innodb_encrypt_log.result
index b999e8cb34a..cd37330f2b0 100644
--- a/mysql-test/suite/encryption/r/innodb_encrypt_log.result
+++ b/mysql-test/suite/encryption/r/innodb_encrypt_log.result
@@ -7,7 +7,7 @@
 #
 SET GLOBAL innodb_log_checksums=0;
 Warnings:
-Warning	138	innodb_encrypt_log implies innodb_log_checksums
+Warning	138	innodb_log_checksums is deprecated and has no effect outside recovery
 SELECT @@global.innodb_log_checksums;
 @@global.innodb_log_checksums
 1
diff --git a/mysql-test/suite/innodb/r/foreign_key.result b/mysql-test/suite/innodb/r/foreign_key.result
index dffb718feb6..49206c7c723 100644
--- a/mysql-test/suite/innodb/r/foreign_key.result
+++ b/mysql-test/suite/innodb/r/foreign_key.result
@@ -658,6 +658,7 @@ SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
 # MDEV-17187 table doesn't exist in engine after ALTER other tables
 # with CONSTRAINTs
 #
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`\\.`t2` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 set foreign_key_checks=on;
 create table t1 (id int not null primary key) engine=innodb;
 create table t2 (id int not null primary key, fid int not null,
@@ -713,4 +714,30 @@ drop table t1,t2;
 ERROR 23000: Cannot delete or update a parent row: a foreign key constraint fails
 drop table t1,t2;
 ERROR 42S02: Unknown table 'test.t2'
+#
+# MDEV-22934 Table disappear after two alter table command
+#
+CREATE TABLE t1(f1 INT NOT NULL AUTO_INCREMENT,
+f2 INT NOT NULL,
+PRIMARY KEY (f1), INDEX (f2))ENGINE=InnoDB;
+CREATE TABLE t2(f1 INT NOT NULL,
+f2 INT NOT NULL, f3 INT NOT NULL,
+PRIMARY KEY(f1, f2), UNIQUE KEY(f2),
+CONSTRAINT `t2_ibfk_1` FOREIGN KEY (f2) REFERENCES t1(f2) ON DELETE CASCADE,
+CONSTRAINT `t2_ibfk_2` FOREIGN KEY (f1) REFERENCES t1(f1) ON DELETE CASCADE
+) ENGINE=InnoDB;
+SET FOREIGN_KEY_CHECKS=0;
+ALTER TABLE t2 DROP PRIMARY KEY, ADD PRIMARY KEY(f3), ALGORITHM=INPLACE;
+ALTER TABLE t2 DROP INDEX `f2`, ALGORITHM=COPY;
+SHOW CREATE TABLE t2;
+Table	Create Table
+t2	CREATE TABLE `t2` (
+  `f1` int(11) NOT NULL,
+  `f2` int(11) NOT NULL,
+  `f3` int(11) NOT NULL,
+  PRIMARY KEY (`f3`)
+) ENGINE=InnoDB DEFAULT CHARSET=latin1
+CREATE TABLE t2 (f1 INT NOT NULL)ENGINE=InnoDB;
+ERROR 42S01: Table 't2' already exists
+DROP TABLE t2, t1;
 # End of 10.2 tests
diff --git a/mysql-test/suite/innodb/r/innodb.result b/mysql-test/suite/innodb/r/innodb.result
index 86f90c2bd79..233023e63c2 100644
--- a/mysql-test/suite/innodb/r/innodb.result
+++ b/mysql-test/suite/innodb/r/innodb.result
@@ -2543,7 +2543,6 @@ set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb;
 create table t1(a varchar(10) primary key) engine = innodb;
 alter table t1 modify column a int;
-Got one of the listed errors
 set foreign_key_checks=1;
 drop table t2,t1;
 set foreign_key_checks=0;
@@ -2552,6 +2551,7 @@ create table t1(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=latin
 alter table t1 convert to character set utf8;
 set foreign_key_checks=1;
 drop table t2,t1;
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`.`t1` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb DEFAULT CHARSET=latin1;
 create table t3(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=utf8;
diff --git a/mysql-test/suite/innodb/t/foreign_key.test b/mysql-test/suite/innodb/t/foreign_key.test
index 27fa63f144e..40bc3a32a4f 100644
--- a/mysql-test/suite/innodb/t/foreign_key.test
+++ b/mysql-test/suite/innodb/t/foreign_key.test
@@ -657,6 +657,8 @@ SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
 --echo # with CONSTRAINTs
 --echo #
 
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`\\.`t2` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
+
 set foreign_key_checks=on;
 create table t1 (id int not null primary key) engine=innodb;
 create table t2 (id int not null primary key, fid int not null,
@@ -698,6 +700,27 @@ drop table t1,t2;
 --error ER_BAD_TABLE_ERROR
 drop table t1,t2;
 
+--echo #
+--echo # MDEV-22934 Table disappear after two alter table command
+--echo #
+CREATE TABLE t1(f1 INT NOT NULL AUTO_INCREMENT,
+		f2 INT NOT NULL,
+		PRIMARY KEY (f1), INDEX (f2))ENGINE=InnoDB;
+CREATE TABLE t2(f1 INT NOT NULL,
+		f2 INT NOT NULL, f3 INT NOT NULL,
+		PRIMARY KEY(f1, f2), UNIQUE KEY(f2),
+CONSTRAINT `t2_ibfk_1` FOREIGN KEY (f2) REFERENCES t1(f2) ON DELETE CASCADE,
+CONSTRAINT `t2_ibfk_2` FOREIGN KEY (f1) REFERENCES t1(f1) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
+SET FOREIGN_KEY_CHECKS=0;
+ALTER TABLE t2 DROP PRIMARY KEY, ADD PRIMARY KEY(f3), ALGORITHM=INPLACE;
+ALTER TABLE t2 DROP INDEX `f2`, ALGORITHM=COPY;
+SHOW CREATE TABLE t2;
+--error ER_TABLE_EXISTS_ERROR
+CREATE TABLE t2 (f1 INT NOT NULL)ENGINE=InnoDB;
+DROP TABLE t2, t1;
+
 --echo # End of 10.2 tests
 
 --source include/wait_until_count_sessions.inc
diff --git a/mysql-test/suite/innodb/t/innodb.test b/mysql-test/suite/innodb/t/innodb.test
index 2ea6d05d9eb..37708a4536d 100644
--- a/mysql-test/suite/innodb/t/innodb.test
+++ b/mysql-test/suite/innodb/t/innodb.test
@@ -1627,7 +1627,6 @@ drop table t1;
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb;
 create table t1(a varchar(10) primary key) engine = innodb;
--- error 1025,1025
 alter table t1 modify column a int;
 set foreign_key_checks=1;
 drop table t2,t1;
@@ -1643,6 +1642,7 @@ drop table t2,t1;
 
 # test that RENAME does not allow invalid charsets when f_k_c is 0
 
+call mtr.add_suppression("\\[Warning\\] InnoDB: In ALTER TABLE `test`.`t1` has or is referenced in foreign key constraints which are not compatible with the new table definition.");
 set foreign_key_checks=0;
 create table t2 (a varchar(10), foreign key (a) references t1(a)) engine = innodb DEFAULT CHARSET=latin1;
 create table t3(a varchar(10) primary key) engine = innodb DEFAULT CHARSET=utf8;
diff --git a/mysql-test/suite/sys_vars/r/innodb_log_checksums_basic.result b/mysql-test/suite/sys_vars/r/innodb_log_checksums_basic.result
index 6679ca87249..7724ef9c2ee 100644
--- a/mysql-test/suite/sys_vars/r/innodb_log_checksums_basic.result
+++ b/mysql-test/suite/sys_vars/r/innodb_log_checksums_basic.result
@@ -28,9 +28,11 @@ SELECT @@global.innodb_log_checksums;
 @@global.innodb_log_checksums
 1
 SET GLOBAL innodb_log_checksums = OFF;
+Warnings:
+Warning	138	innodb_log_checksums is deprecated and has no effect outside recovery
 SELECT @@global.innodb_log_checksums;
 @@global.innodb_log_checksums
-0
+1
 SET GLOBAL innodb_log_checksums = default;
 SET GLOBAL innodb_log_checksums = ON;
 SELECT @@global.innodb_log_checksums;
diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
index c34c4748493..2bd2920ff9d 100644
--- a/mysql-test/suite/sys_vars/r/sysvars_innodb.result
+++ b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
@@ -1250,7 +1250,7 @@ SESSION_VALUE	NULL
 DEFAULT_VALUE	ON
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	BOOLEAN
-VARIABLE_COMMENT	Whether to compute and require checksums for InnoDB redo log blocks
+VARIABLE_COMMENT	DEPRECATED. Whether to require checksums for InnoDB redo log blocks.
 NUMERIC_MIN_VALUE	NULL
 NUMERIC_MAX_VALUE	NULL
 NUMERIC_BLOCK_SIZE	NULL
diff --git a/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink.result b/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink.result
index 51c2e204b78..bcd96b86516 100644
--- a/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink.result
+++ b/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink.result
@@ -15,6 +15,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -32,6 +33,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/ignored.tab' as time zone. Skipping it.
 Warning: Skipping directory 'MYSQLTEST_VARDIR/zoneinfo/posix/posix': to avoid infinite symlink recursion.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 \d |
@@ -57,6 +59,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -71,6 +74,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
  (@time_zone_id, 0, 0, 0, 'GMT')
 ;
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 \d |
diff --git a/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink_skip.result b/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink_skip.result
index 85c4d858be2..aff02cb413e 100644
--- a/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink_skip.result
+++ b/mysql-test/suite/wsrep/r/mysql_tzinfo_to_sql_symlink_skip.result
@@ -9,6 +9,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -26,6 +27,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/ignored.tab' as time zone. Skipping it.
 Warning: Skipping directory 'MYSQLTEST_VARDIR/zoneinfo/posix/posix': to avoid infinite symlink recursion.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 # Silent run
@@ -36,6 +38,7 @@ TRUNCATE TABLE time_zone;
 TRUNCATE TABLE time_zone_name;
 TRUNCATE TABLE time_zone_transition;
 TRUNCATE TABLE time_zone_transition_type;
+START TRANSACTION;
 INSERT INTO time_zone (Use_leap_seconds) VALUES ('N');
 SET @time_zone_id= LAST_INSERT_ID();
 INSERT INTO time_zone_name (Name, Time_zone_id) VALUES ('GMT', @time_zone_id);
@@ -50,6 +53,7 @@ INSERT INTO time_zone_transition_type (Time_zone_id, Transition_type_id, Offset,
  (@time_zone_id, 0, 0, 0, 'GMT')
 ;
 Warning: Unable to load 'MYSQLTEST_VARDIR/zoneinfo/posix/garbage' as time zone. Skipping it.
+COMMIT;
 ALTER TABLE time_zone_transition ORDER BY Time_zone_id, Transition_time;
 ALTER TABLE time_zone_transition_type ORDER BY Time_zone_id, Transition_type_id;
 #
diff --git a/mysys/stacktrace.c b/mysys/stacktrace.c
index a512f5879d6..f5e6352a72e 100644
--- a/mysys/stacktrace.c
+++ b/mysys/stacktrace.c
@@ -34,108 +34,11 @@
 #include <execinfo.h>
 #endif
 
-#ifdef __linux__
-#define PTR_SANE(p) ((p) && (char*)(p) >= heap_start && (char*)(p) <= heap_end)
-static char *heap_start;
-char *__bss_start;
-#else
-#define PTR_SANE(p) (p)
-#endif /* __linux */
-
-
-void my_init_stacktrace()
-{
-#ifdef __linux__
-  heap_start = (char*) &__bss_start;
-#endif /* __linux */
-}
-
-#ifdef __linux__
-
-static void print_buffer(char *buffer, size_t count)
-{
-  const char s[]= " ";
-  for (; count && *buffer; --count)
-  {
-    my_write_stderr(isprint(*buffer) ? buffer : s, 1);
-    ++buffer;
-  }
-}
-
-/**
-  Access the pages of this process through /proc/self/task/<tid>/mem
-  in order to safely print the contents of a memory address range.
-
-  @param  addr      The address at the start of the memory region.
-  @param  max_len   The length of the memory region.
-
-  @return Zero on success.
-*/
-static int safe_print_str(const char *addr, size_t max_len)
-{
-  int fd;
-  pid_t tid;
-  off_t offset;
-  ssize_t nbytes= 0;
-  size_t total, count;
-  char buf[256];
-
-  tid= (pid_t) syscall(SYS_gettid);
-
-  sprintf(buf, "/proc/self/task/%d/mem", tid);
-
-  if ((fd= open(buf, O_RDONLY)) < 0)
-    return -1;
-
-  /* Ensure that off_t can hold a pointer. */
-  compile_time_assert(sizeof(off_t) >= sizeof(intptr));
-
-  total= max_len;
-  offset= (intptr) addr;
-
-  /* Read up to the maximum number of bytes. */
-  while (total)
-  {
-    count= MY_MIN(sizeof(buf), total);
-
-    if ((nbytes= pread(fd, buf, count, offset)) < 0)
-    {
-      /* Just in case... */
-      if (errno == EINTR)
-        continue;
-      else
-        break;
-    }
-
-    /* Advance offset into memory. */
-    total-= nbytes;
-    offset+= nbytes;
-    addr+= nbytes;
-
-    /* Output the printable characters. */
-    print_buffer(buf, nbytes);
-
-    /* Break if less than requested... */
-    if ((count - nbytes))
-      break;
-  }
-
-  if (nbytes == -1)
-    my_safe_printf_stderr("Can't read from address %p", addr);
-
-  close(fd);
-
-  return 0;
-}
-
-#endif
-
 /*
   Attempt to print a char * pointer as a string.
 
   SYNOPSIS
-    Prints either until the end of string ('\0'), or max_len characters have
-    been printed.
+    Prints until  max_len characters have been printed.
 
   RETURN VALUE
     0  Pointer was within the heap address space.
@@ -150,24 +53,25 @@ static int safe_print_str(const char *addr, size_t max_len)
 
 int my_safe_print_str(const char* val, size_t max_len)
 {
-#ifdef __linux__
-  char *heap_end;
-
-  // Try and make use of /proc filesystem to safely print memory contents.
-  if (!safe_print_str(val, max_len))
-    return 0;
-
-  heap_end= (char*) sbrk(0);
-#endif
-
-  if (!PTR_SANE(val))
+  const char *orig_val= val;
+  if (!val)
   {
-    my_safe_printf_stderr("%s", "is an invalid pointer");
+    my_safe_printf_stderr("%s", "(null)");
     return 1;
   }
 
-  for (; max_len && PTR_SANE(val) && *val; --max_len)
-    my_write_stderr((val++), 1);
+  for (; max_len; --max_len)
+  {
+    if (my_write_stderr((val++), 1) != 1)
+    {
+      if ((errno == EFAULT) &&(val == orig_val + 1))
+      {
+        // We can not read the address from very beginning
+        my_safe_printf_stderr("Can't access address %p", orig_val);
+      }
+      break;
+    }
+  }
   my_safe_printf_stderr("%s", "\n");
 
   return 0;
@@ -511,11 +415,6 @@ static EXCEPTION_POINTERS *exception_ptrs;
 #define MODULE64_SIZE_WINXP 576
 #define STACKWALK_MAX_FRAMES 64
 
-void my_init_stacktrace()
-{
-}
-
-
 void my_set_exception_pointers(EXCEPTION_POINTERS *ep)
 {
   exception_ptrs = ep;
diff --git a/scripts/mysqld_safe.sh b/scripts/mysqld_safe.sh
index f40a68a3b1e..22d5a5531c6 100644
--- a/scripts/mysqld_safe.sh
+++ b/scripts/mysqld_safe.sh
@@ -23,6 +23,7 @@ numa_interleave=0
 wsrep_on=0
 dry_run=0
 defaults_group_suffix=
+ignore_unknown=1
 
 # Initial logging status: error log is not open, and not using syslog
 logging=init
@@ -361,11 +362,22 @@ parse_arguments() {
 
       --help) usage ;;
 
+      --ignore-unknown) ignore_unknown=1 ;;
+      --no-ignore-unknown|--not-ignore-unknown) ignore_unknown=0 ;;
+
       *)
-        case "$unrecognized_handling" in
-          collect) append_arg_to_args "$arg" ;;
-          complain) log_error "unknown option '$arg'" ;;
-        esac
+        if test $ignore_unknown -eq 0
+        then
+          case "$unrecognized_handling" in
+            collect) append_arg_to_args "$arg" ;;
+            complain) log_error "unknown option '$arg'"
+          esac
+        else
+          case "$arg" in
+            "--loose-"*) append_arg_to_args "$arg" ;;
+            *)           append_arg_to_args "--loose-$arg"
+          esac
+        fi
     esac
   done
 }
diff --git a/sql/mysqld.cc b/sql/mysqld.cc
index 3a509fb8beb..377d549a045 100644
--- a/sql/mysqld.cc
+++ b/sql/mysqld.cc
@@ -3389,7 +3389,6 @@ void init_signals(void)
     sigemptyset(&sa.sa_mask);
     sigprocmask(SIG_SETMASK,&sa.sa_mask,NULL);
 
-    my_init_stacktrace();
 #if defined(__amiga__)
     sa.sa_handler=(void(*)())handle_fatal_signal;
 #else
diff --git a/sql/tztime.cc b/sql/tztime.cc
index ca4c10975ca..4ef20d79d5d 100644
--- a/sql/tztime.cc
+++ b/sql/tztime.cc
@@ -2739,9 +2739,11 @@ main(int argc, char **argv)
     printf("TRUNCATE TABLE time_zone_name;\n");
     printf("TRUNCATE TABLE time_zone_transition;\n");
     printf("TRUNCATE TABLE time_zone_transition_type;\n");
+    printf("START TRANSACTION;\n");
 
     if (scan_tz_dir(root_name_end, 0, opt_verbose))
     {
+      printf("ROLLBACK;\n");
       fflush(stdout);
       fprintf(stderr,
               "There were fatal errors during processing "
@@ -2749,6 +2751,7 @@ main(int argc, char **argv)
       return 1;
     }
 
+    printf("COMMIT;\n");
     printf("ALTER TABLE time_zone_transition "
            "ORDER BY Time_zone_id, Transition_time;\n");
     printf("ALTER TABLE time_zone_transition_type "
diff --git a/storage/innobase/btr/btr0cur.cc b/storage/innobase/btr/btr0cur.cc
index fffa36475e6..a68bc6550d7 100644
--- a/storage/innobase/btr/btr0cur.cc
+++ b/storage/innobase/btr/btr0cur.cc
@@ -3360,7 +3360,7 @@ fail:
 
 		/* prefetch siblings of the leaf for the pessimistic
 		operation, if the page is leaf. */
-		if (page_is_leaf(page)) {
+		if (page_is_leaf(page) && !index->is_ibuf()) {
 			btr_cur_prefetch_siblings(block);
 		}
 fail_err:
@@ -4330,6 +4330,7 @@ btr_cur_optimistic_update(
 
 	if (rec_offs_any_extern(*offsets)) {
 any_extern:
+		ut_ad(!index->is_ibuf());
 		/* Externally stored fields are treated in pessimistic
 		update */
 
@@ -4525,7 +4526,7 @@ func_exit:
 		}
 	}
 
-	if (err != DB_SUCCESS) {
+	if (err != DB_SUCCESS && !index->is_ibuf()) {
 		/* prefetch siblings of the leaf for the pessimistic
 		operation. */
 		btr_cur_prefetch_siblings(block);
diff --git a/storage/innobase/buf/buf0buf.cc b/storage/innobase/buf/buf0buf.cc
index 076b9c33c00..ea1916e192d 100644
--- a/storage/innobase/buf/buf0buf.cc
+++ b/storage/innobase/buf/buf0buf.cc
@@ -5653,7 +5653,23 @@ buf_page_create(
 
 		if (drop_hash_entry) {
 			mutex_enter(&block->mutex);
-			buf_page_set_sticky(&block->page);
+			/* Avoid a hang if I/O is going on. Release
+			the buffer pool mutex and page hash lock
+			and wait for I/O to complete */
+			while (buf_block_get_io_fix(block) != BUF_IO_NONE) {
+				buf_block_fix(block);
+				mutex_exit(&block->mutex);
+				buf_pool_mutex_exit(buf_pool);
+				rw_lock_x_unlock(hash_lock);
+
+				os_thread_yield();
+
+				buf_pool_mutex_enter(buf_pool);
+				rw_lock_x_lock(hash_lock);
+				mutex_enter(&block->mutex);
+				buf_block_unfix(block);
+			}
+			rw_lock_x_lock(&block->lock);
 			mutex_exit(&block->mutex);
 		}
 #endif
@@ -5665,11 +5681,7 @@ buf_page_create(
 #ifdef BTR_CUR_HASH_ADAPT
 		if (drop_hash_entry) {
 			btr_search_drop_page_hash_index(block);
-			buf_pool_mutex_enter(buf_pool);
-			mutex_enter(&block->mutex);
-			buf_page_unset_sticky(&block->page);
-			mutex_exit(&block->mutex);
-			buf_pool_mutex_exit(buf_pool);
+			rw_lock_x_unlock(&block->lock);
 		}
 #endif /* BTR_CUR_HASH_ADAPT */
 
diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index e1acc7b9095..6f56a09eda2 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -3116,7 +3116,7 @@ DECLARE_THREAD(buf_flush_page_cleaner_coordinator)(void*)
 		/* The page_cleaner skips sleep if the server is
 		idle and there are no pending IOs in the buffer pool
 		and there is work to do. */
-		if (srv_check_activity(&last_activity)
+		if (srv_check_activity(last_activity)
 		    || buf_get_n_pending_read_ios()
 		    || n_flushed == 0) {
 
@@ -3208,7 +3208,7 @@ DECLARE_THREAD(buf_flush_page_cleaner_coordinator)(void*)
 
 			n_flushed = n_flushed_lru + n_flushed_list;
 
-		} else if (srv_check_activity(&last_activity)) {
+		} else if (srv_check_activity(last_activity)) {
 			ulint	n_to_flush;
 			lsn_t	lsn_limit = 0;
 
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index c87e396b0de..21b68dd0fb3 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -447,6 +447,14 @@ TYPELIB innodb_flush_method_typelib = {
 	NULL
 };
 
+/* The following counter is used to convey information to InnoDB
+about server activity: in case of normal DML ops it is not
+sensible to call srv_active_wake_master_thread after each
+operation, we only do it every INNOBASE_WAKE_INTERVAL'th step. */
+
+#define INNOBASE_WAKE_INTERVAL	32
+static ulong	innobase_active_counter	= 0;
+
 /** Allowed values of innodb_change_buffering */
 static const char* innodb_change_buffering_names[] = {
 	"none",		/* IBUF_USE_NONE */
@@ -1844,6 +1852,23 @@ thd_to_trx_id(
 #endif /* WITH_WSREP */
 
 /********************************************************************//**
+Increments innobase_active_counter and every INNOBASE_WAKE_INTERVALth
+time calls srv_active_wake_master_thread. This function should be used
+when a single database operation may introduce a small need for
+server utility activity, like checkpointing. */
+inline
+void
+innobase_active_small(void)
+/*=======================*/
+{
+	innobase_active_counter++;
+
+	if ((innobase_active_counter % INNOBASE_WAKE_INTERVAL) == 0) {
+		srv_active_wake_master_thread();
+	}
+}
+
+/********************************************************************//**
 Converts an InnoDB error code to a MySQL error code and also tells to MySQL
 about a possible transaction rollback inside InnoDB caused by a lock wait
 timeout or a deadlock.
@@ -3488,8 +3513,7 @@ static int innodb_init_abort()
 	DBUG_RETURN(1);
 }
 
-/** Update log_checksum_algorithm_ptr with a pointer to the function
-corresponding to whether checksums are enabled.
+/** If applicable, emit a message that log checksums cannot be disabled.
 @param[in,out]	thd	client session, or NULL if at startup
 @param[in]	check	whether redo log block checksums are enabled
 @return whether redo log block checksums are enabled */
@@ -3497,34 +3521,21 @@ static inline
 bool
 innodb_log_checksums_func_update(THD* thd, bool check)
 {
-	static const char msg[] = "innodb_encrypt_log implies"
-		" innodb_log_checksums";
+	static const char msg[] = "innodb_log_checksums is deprecated"
+		" and has no effect outside recovery";
 
 	ut_ad(!thd == !srv_was_started);
 
 	if (!check) {
-		check = srv_encrypt_log;
-		if (!check) {
-		} else if (thd) {
+		if (thd) {
 			push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN,
 					    HA_ERR_UNSUPPORTED, msg);
+			check = true;
 		} else {
 			sql_print_warning(msg);
 		}
 	}
 
-	if (thd) {
-		log_mutex_enter();
-		log_checksum_algorithm_ptr = check
-			? log_block_calc_checksum_crc32
-			: log_block_calc_checksum_none;
-		log_mutex_exit();
-	} else {
-		log_checksum_algorithm_ptr = check
-			? log_block_calc_checksum_crc32
-			: log_block_calc_checksum_none;
-	}
-
 	return(check);
 }
 
@@ -6456,6 +6467,11 @@ ha_innobase::close()
 
 	MONITOR_INC(MONITOR_TABLE_CLOSE);
 
+	/* Tell InnoDB server that there might be work for
+	utility threads: */
+
+	srv_active_wake_master_thread();
+
 	DBUG_RETURN(0);
 }
 
@@ -8166,6 +8182,8 @@ report_error:
 	}
 
 func_exit:
+	innobase_active_small();
+
 	DBUG_RETURN(error_result);
 }
 
@@ -8852,6 +8870,11 @@ func_exit:
 			error, m_prebuilt->table->flags, m_user_thd);
 	}
 
+	/* Tell InnoDB server that there might be work for
+	utility threads: */
+
+	innobase_active_small();
+
 #ifdef WITH_WSREP
 	if (error == DB_SUCCESS && trx->is_wsrep() &&
 	    wsrep_thd_exec_mode(m_user_thd) == LOCAL_STATE &&
@@ -8910,6 +8933,11 @@ ha_innobase::delete_row(
 
 	innobase_srv_conc_exit_innodb(m_prebuilt);
 
+	/* Tell the InnoDB server that there might be work for
+	utility threads: */
+
+	innobase_active_small();
+
 #ifdef WITH_WSREP
 	if (error == DB_SUCCESS && trx->is_wsrep()
 	    && wsrep_thd_exec_mode(m_user_thd) == LOCAL_STATE
@@ -12697,6 +12725,7 @@ create_table_info_t::create_table_update_dict()
 	if (m_flags2 & DICT_TF2_FTS) {
 		if (!innobase_fts_load_stopword(innobase_table, NULL, m_thd)) {
 			dict_table_close(innobase_table, FALSE, FALSE);
+			srv_active_wake_master_thread();
 			trx_free(m_trx);
 			DBUG_RETURN(-1);
 		}
@@ -12846,6 +12875,11 @@ ha_innobase::create(
 
 	error = info.create_table_update_dict();
 
+	/* Tell the InnoDB server that there might be work for
+	utility threads: */
+
+	srv_active_wake_master_thread();
+
 	DBUG_RETURN(error);
 }
 
@@ -19068,7 +19102,7 @@ static MYSQL_SYSVAR_ENUM(checksum_algorithm, srv_checksum_algorithm,
 
 static MYSQL_SYSVAR_BOOL(log_checksums, innodb_log_checksums,
   PLUGIN_VAR_RQCMDARG,
-  "Whether to compute and require checksums for InnoDB redo log blocks",
+  "DEPRECATED. Whether to require checksums for InnoDB redo log blocks.",
   NULL, innodb_log_checksums_update, TRUE);
 
 static MYSQL_SYSVAR_BOOL(checksums, innobase_use_checksums,
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 98d68250029..896052f34ac 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -9415,11 +9415,11 @@ ha_innobase::commit_inplace_alter_table(
 
 		/* Exclusively lock the table, to ensure that no other
 		transaction is holding locks on the table while we
-		change the table definition. The MySQL meta-data lock
+		change the table definition. The meta-data lock (MDL)
 		should normally guarantee that no conflicting locks
 		exist. However, FOREIGN KEY constraints checks and any
 		transactions collected during crash recovery could be
-		holding InnoDB locks only, not MySQL locks. */
+		holding InnoDB locks only, not MDL. */
 
 		dberr_t error = row_merge_lock_table(
 			m_prebuilt->trx, ctx->old_table, LOCK_X);
@@ -9795,6 +9795,11 @@ foreign_fail:
 
 	log_append_on_checkpoint(NULL);
 
+	/* Tell the InnoDB server that there might be work for
+	utility threads: */
+
+	srv_active_wake_master_thread();
+
 	if (fail) {
 		for (inplace_alter_handler_ctx** pctx = ctx_array;
 		     *pctx; pctx++) {
diff --git a/storage/innobase/include/dict0mem.h b/storage/innobase/include/dict0mem.h
index 2504b2ef61d..59723a3c178 100644
--- a/storage/innobase/include/dict0mem.h
+++ b/storage/innobase/include/dict0mem.h
@@ -1041,6 +1041,9 @@ struct dict_index_t{
 	/** @return whether this is a spatial index */
 	bool is_spatial() const { return UNIV_UNLIKELY(type & DICT_SPATIAL); }
 
+	/** @return whether this is the change buffer */
+	bool is_ibuf() const { return UNIV_UNLIKELY(type & DICT_IBUF); }
+
 	/** @return whether the index includes virtual columns */
 	bool has_virtual() const { return type & DICT_VIRTUAL; }
 
diff --git a/storage/innobase/include/log0log.h b/storage/innobase/include/log0log.h
index 133b1692d31..b201de06d17 100644
--- a/storage/innobase/include/log0log.h
+++ b/storage/innobase/include/log0log.h
@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All rights reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2017, 2019, MariaDB Corporation.
+Copyright (c) 2017, 2020, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -56,12 +56,6 @@ step which modifies the database, is started */
 #define LOG_CHECKPOINT_FREE_PER_THREAD	(4U << srv_page_size_shift)
 #define LOG_CHECKPOINT_EXTRA_FREE	(8U << srv_page_size_shift)
 
-typedef ulint (*log_checksum_func_t)(const byte* log_block);
-
-/** Pointer to the log checksum calculation function. Protected with
-log_sys.mutex. */
-extern log_checksum_func_t log_checksum_algorithm_ptr;
-
 /** Append a string to the log.
 @param[in]	str		string
 @param[in]	len		string length
@@ -266,14 +260,6 @@ log_block_set_data_len(
 /*===================*/
 	byte*	log_block,	/*!< in/out: log block */
 	ulint	len);		/*!< in: data length */
-/************************************************************//**
-Calculates the checksum for a log block.
-@return checksum */
-UNIV_INLINE
-ulint
-log_block_calc_checksum(
-/*====================*/
-	const byte*	block);	/*!< in: log block */
 
 /** Calculates the checksum for a log block using the CRC32 algorithm.
 @param[in]	block	log block
@@ -283,12 +269,6 @@ ulint
 log_block_calc_checksum_crc32(
 	const byte*	block);
 
-/** Calculates the checksum for a log block using the "no-op" algorithm.
-@return		the calculated checksum value */
-UNIV_INLINE
-ulint
-log_block_calc_checksum_none(const byte*);
-
 /************************************************************//**
 Gets a log block checksum field value.
 @return checksum */
@@ -365,7 +345,7 @@ void
 log_refresh_stats(void);
 /*===================*/
 
-/** Whether to generate and require checksums on the redo log pages */
+/** Whether to require checksums on the redo log pages */
 extern my_bool	innodb_log_checksums;
 
 /* Values used as flags */
diff --git a/storage/innobase/include/log0log.ic b/storage/innobase/include/log0log.ic
index 722e658a24b..be28fee7b8e 100644
--- a/storage/innobase/include/log0log.ic
+++ b/storage/innobase/include/log0log.ic
@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2018, MariaDB Corporation.
+Copyright (c) 2017, 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
@@ -190,18 +190,6 @@ log_block_convert_lsn_to_no(
 			0xFUL, 0x3FFFFFFFUL)) + 1);
 }
 
-/************************************************************//**
-Calculates the checksum for a log block.
-@return checksum */
-UNIV_INLINE
-ulint
-log_block_calc_checksum(
-/*====================*/
-	const byte*	block)	/*!< in: log block */
-{
-	return(log_checksum_algorithm_ptr(block));
-}
-
 /** Calculate the checksum for a log block using the pre-5.7.9 algorithm.
 @param[in]	block	log block
 @return		checksum */
@@ -242,15 +230,6 @@ log_block_calc_checksum_crc32(
 	return(ut_crc32(block, OS_FILE_LOG_BLOCK_SIZE - LOG_BLOCK_TRL_SIZE));
 }
 
-/** Calculates the checksum for a log block using the "no-op" algorithm.
-@return        checksum */
-UNIV_INLINE
-ulint
-log_block_calc_checksum_none(const byte*)
-{
-	return(LOG_NO_CHECKSUM_MAGIC);
-}
-
 /************************************************************//**
 Gets a log block checksum field value.
 @return checksum */
diff --git a/storage/innobase/include/srv0srv.h b/storage/innobase/include/srv0srv.h
index 93755ad7520..6c575733710 100644
--- a/storage/innobase/include/srv0srv.h
+++ b/storage/innobase/include/srv0srv.h
@@ -788,6 +788,19 @@ srv_reset_io_thread_op_info();
 /** Wake up the purge threads if there is work to do. */
 void
 srv_wake_purge_thread_if_not_active();
+/** Wake up the InnoDB master thread if it was suspended (not sleeping). */
+void
+srv_active_wake_master_thread_low();
+
+#define srv_active_wake_master_thread()					\
+	do {								\
+		if (!srv_read_only_mode) {				\
+			srv_active_wake_master_thread_low();		\
+		}							\
+	} while (0)
+/** Wake up the master thread if it is suspended or being suspended. */
+void
+srv_wake_master_thread();
 
 /******************************************************************//**
 Outputs to a file the output of the InnoDB Monitor.
@@ -816,13 +829,13 @@ reading this value as it is only used in heuristics.
 ulint
 srv_get_activity_count(void);
 /*========================*/
-
-/** Check if there has been any activity.
-@param[in,out]  activity_count  recent activity count to be returned
-if there is a change
+/*******************************************************************//**
+Check if there has been any activity.
 @return FALSE if no change in activity counter. */
-bool srv_check_activity(ulint *activity_count);
-
+ibool
+srv_check_activity(
+/*===============*/
+	ulint		old_activity_count);	/*!< old activity count */
 /******************************************************************//**
 Increment the server activity counter. */
 void
diff --git a/storage/innobase/log/log0log.cc b/storage/innobase/log/log0log.cc
index e8f39e03b50..997430497bc 100644
--- a/storage/innobase/log/log0log.cc
+++ b/storage/innobase/log/log0log.cc
@@ -2,7 +2,7 @@
 
 Copyright (c) 1995, 2017, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2009, Google Inc.
-Copyright (c) 2014, 2019, MariaDB Corporation.
+Copyright (c) 2014, 2020, MariaDB Corporation.
 
 Portions of this file contain modifications contributed and copyrighted by
 Google, Inc. Those modifications are gratefully acknowledged and are described
@@ -83,12 +83,9 @@ reduce the size of the log.
 /** Redo log system */
 log_t	log_sys;
 
-/** Whether to generate and require checksums on the redo log pages */
+/** Whether to require checksums on the redo log pages */
 my_bool	innodb_log_checksums;
 
-/** Pointer to the log checksum calculation function */
-log_checksum_func_t log_checksum_algorithm_ptr;
-
 /* Next log block number to do dummy record filling if no log records written
 for a while */
 static ulint		next_lbn_to_pad = 0;
@@ -679,7 +676,7 @@ log_block_store_checksum(
 /*=====================*/
 	byte*	block)	/*!< in/out: pointer to a log block */
 {
-	log_block_set_checksum(block, log_block_calc_checksum(block));
+	log_block_set_checksum(block, log_block_calc_checksum_crc32(block));
 }
 
 /******************************************************//**
diff --git a/storage/innobase/log/log0recv.cc b/storage/innobase/log/log0recv.cc
index a9b5b1e25d0..b6f6bc26165 100644
--- a/storage/innobase/log/log0recv.cc
+++ b/storage/innobase/log/log0recv.cc
@@ -1199,7 +1199,10 @@ static dberr_t recv_log_recover_10_4()
 			% univ_page_size.physical()),
 	       OS_FILE_LOG_BLOCK_SIZE, buf, NULL);
 
-	if (log_block_calc_checksum(buf) != log_block_get_checksum(buf)) {
+	const ulint cksum = log_block_get_checksum(buf);
+
+	if (cksum != LOG_NO_CHECKSUM_MAGIC
+	    && cksum != log_block_calc_checksum_crc32(buf)) {
 		return DB_CORRUPTION;
 	}
 
diff --git a/storage/innobase/row/row0mysql.cc b/storage/innobase/row/row0mysql.cc
index 0c5f96e20a5..5dcd596fc98 100644
--- a/storage/innobase/row/row0mysql.cc
+++ b/storage/innobase/row/row0mysql.cc
@@ -3817,7 +3817,7 @@ funct_exit_all_freed:
 
 	trx->op_info = "";
 
-	srv_inc_activity_count();
+	srv_wake_master_thread();
 
 	DBUG_RETURN(err);
 }
@@ -4528,12 +4528,20 @@ end:
 		if (err != DB_SUCCESS) {
 
 			if (old_is_tmp) {
-				ib::error() << "In ALTER TABLE "
+				/* In case of copy alter, ignore the
+				loading of foreign key constraint
+				when foreign_key_check is disabled */
+				ib::error_or_warn(trx->check_foreigns)
+					<< "In ALTER TABLE "
 					<< ut_get_name(trx, new_name)
 					<< " has or is referenced in foreign"
 					" key constraints which are not"
 					" compatible with the new table"
 					" definition.";
+				if (!trx->check_foreigns) {
+					err = DB_SUCCESS;
+					goto funct_exit;
+				}
 			} else {
 				ib::error() << "In RENAME TABLE table "
 					<< ut_get_name(trx, new_name)
diff --git a/storage/innobase/row/row0uins.cc b/storage/innobase/row/row0uins.cc
index 1e560dad7b3..be0f6373e21 100644
--- a/storage/innobase/row/row0uins.cc
+++ b/storage/innobase/row/row0uins.cc
@@ -82,6 +82,7 @@ row_undo_ins_remove_clust_rec(
 		mtr.set_log_mode(MTR_LOG_NO_REDO);
 	} else {
 		index->set_modified(mtr);
+		ut_ad(lock_table_has_locks(index->table));
 	}
 
 	/* This is similar to row_undo_mod_clust(). The DDL thread may
@@ -92,8 +93,7 @@ row_undo_ins_remove_clust_rec(
 
 	online = dict_index_is_online_ddl(index);
 	if (online) {
-		ut_ad(node->trx->dict_operation_lock_mode
-		      != RW_X_LATCH);
+		ut_ad(!node->trx->dict_operation_lock_mode);
 		ut_ad(node->table->id != DICT_INDEXES_ID);
 		mtr_s_lock_index(index, &mtr);
 	}
@@ -568,6 +568,9 @@ row_undo_ins(
 		return(DB_SUCCESS);
 	}
 
+	ut_ad(node->table->is_temporary()
+	      || lock_table_has_locks(node->table));
+
 	/* Iterate over all the indexes and undo the insert.*/
 
 	node->index = dict_table_get_first_index(node->table);
diff --git a/storage/innobase/row/row0umod.cc b/storage/innobase/row/row0umod.cc
index 2ac54c4025e..3e46c2f6123 100644
--- a/storage/innobase/row/row0umod.cc
+++ b/storage/innobase/row/row0umod.cc
@@ -219,10 +219,7 @@ row_undo_mod_clust(
 	bool		online;
 
 	ut_ad(thr_get_trx(thr) == node->trx);
-	ut_ad(node->trx->dict_operation_lock_mode);
 	ut_ad(node->trx->in_rollback);
-	ut_ad(rw_lock_own_flagged(&dict_operation_lock,
-				  RW_LOCK_FLAG_X | RW_LOCK_FLAG_S));
 
 	log_free_check();
 	pcur = &node->pcur;
@@ -234,11 +231,12 @@ row_undo_mod_clust(
 		mtr.set_log_mode(MTR_LOG_NO_REDO);
 	} else {
 		index->set_modified(mtr);
+		ut_ad(lock_table_has_locks(index->table));
 	}
 
 	online = dict_index_is_online_ddl(index);
 	if (online) {
-		ut_ad(node->trx->dict_operation_lock_mode != RW_X_LATCH);
+		ut_ad(!node->trx->dict_operation_lock_mode);
 		mtr_s_lock_index(index, &mtr);
 	}
 
@@ -277,17 +275,7 @@ row_undo_mod_clust(
 		ut_ad(err == DB_SUCCESS || err == DB_OUT_OF_FILE_SPACE);
 	}
 
-	/* Online rebuild cannot be initiated while we are holding
-	dict_operation_lock and index->lock. (It can be aborted.) */
-	ut_ad(online || !dict_index_is_online_ddl(index));
-
-	if (err == DB_SUCCESS && online) {
-
-		ut_ad(rw_lock_own_flagged(
-				&index->lock,
-				RW_LOCK_FLAG_S | RW_LOCK_FLAG_X
-				| RW_LOCK_FLAG_SX));
-
+	if (err == DB_SUCCESS && online && dict_index_is_online_ddl(index)) {
 		switch (node->rec_type) {
 		case TRX_UNDO_DEL_MARK_REC:
 			row_log_table_insert(
@@ -836,37 +824,6 @@ func_exit_no_pcur:
 }
 
 /***********************************************************//**
-Flags a secondary index corrupted. */
-static MY_ATTRIBUTE((nonnull))
-void
-row_undo_mod_sec_flag_corrupted(
-/*============================*/
-	trx_t*		trx,	/*!< in/out: transaction */
-	dict_index_t*	index)	/*!< in: secondary index */
-{
-	ut_ad(!dict_index_is_clust(index));
-
-	switch (trx->dict_operation_lock_mode) {
-	case RW_S_LATCH:
-		/* Because row_undo() is holding an S-latch
-		on the data dictionary during normal rollback,
-		we can only mark the index corrupted in the
-		data dictionary cache. TODO: fix this somehow.*/
-		mutex_enter(&dict_sys->mutex);
-		dict_set_corrupted_index_cache_only(index);
-		mutex_exit(&dict_sys->mutex);
-		break;
-	default:
-		ut_ad(0);
-		/* fall through */
-	case RW_X_LATCH:
-		/* This should be the rollback of a data dictionary
-		transaction. */
-		dict_set_corrupted(index, trx, "rollback");
-	}
-}
-
-/***********************************************************//**
 Undoes a modify in secondary indexes when undo record type is UPD_DEL.
 @return DB_SUCCESS or DB_OUT_OF_FILE_SPACE */
 static MY_ATTRIBUTE((nonnull, warn_unused_result))
@@ -979,8 +936,7 @@ row_undo_mod_del_mark_sec(
 		}
 
 		if (err == DB_DUPLICATE_KEY) {
-			row_undo_mod_sec_flag_corrupted(
-				thr_get_trx(thr), index);
+			index->type |= DICT_CORRUPT;
 			err = DB_SUCCESS;
 			/* Do not return any error to the caller. The
 			duplicate will be reported by ALTER TABLE or
@@ -1125,8 +1081,7 @@ row_undo_mod_upd_exist_sec(
 		}
 
 		if (err == DB_DUPLICATE_KEY) {
-			row_undo_mod_sec_flag_corrupted(
-				thr_get_trx(thr), index);
+			index->type |= DICT_CORRUPT;
 			err = DB_SUCCESS;
 		} else if (err != DB_SUCCESS) {
 			break;
@@ -1292,6 +1247,8 @@ row_undo_mod(
 		return(DB_SUCCESS);
 	}
 
+	ut_ad(node->table->is_temporary()
+	      || lock_table_has_locks(node->table));
 	node->index = dict_table_get_first_index(node->table);
 	ut_ad(dict_index_is_clust(node->index));
 
diff --git a/storage/innobase/row/row0undo.cc b/storage/innobase/row/row0undo.cc
index 762228503be..68b8123cbb6 100644
--- a/storage/innobase/row/row0undo.cc
+++ b/storage/innobase/row/row0undo.cc
@@ -283,15 +283,16 @@ row_undo(
 			? UNDO_NODE_INSERT : UNDO_NODE_MODIFY;
 	}
 
-	/* Prevent DROP TABLE etc. while we are rolling back this row.
-	If we are doing a TABLE CREATE or some other dictionary operation,
-	then we already have dict_operation_lock locked in x-mode. Do not
-	try to lock again, because that would cause a hang. */
-
-	const bool locked_data_dict = (trx->dict_operation_lock_mode == 0);
-
-	if (locked_data_dict) {
-
+	/* Prevent prepare_inplace_alter_table_dict() from adding
+	dict_table_t::indexes while we are processing the record.
+	Recovered transactions are not protected by MDL, and the
+	secondary index creation is not protected by table locks
+	for online operation. (A table lock would only be acquired
+	when committing the ALTER TABLE operation.) */
+	const bool locked_data_dict = UNIV_UNLIKELY(trx->is_recovered)
+		&& !trx->dict_operation_lock_mode;
+
+	if (UNIV_UNLIKELY(locked_data_dict)) {
 		row_mysql_freeze_data_dictionary(trx);
 	}
 
@@ -307,8 +308,7 @@ row_undo(
 		err = row_undo_mod(node, thr);
 	}
 
-	if (locked_data_dict) {
-
+	if (UNIV_UNLIKELY(locked_data_dict)) {
 		row_mysql_unfreeze_data_dictionary(trx);
 	}
 
diff --git a/storage/innobase/srv/srv0srv.cc b/storage/innobase/srv/srv0srv.cc
index 6af3b89f15c..c5b08cd5eb8 100644
--- a/storage/innobase/srv/srv0srv.cc
+++ b/storage/innobase/srv/srv0srv.cc
@@ -1923,6 +1923,33 @@ srv_get_active_thread_type(void)
 	return(ret);
 }
 
+/** Wake up the InnoDB master thread if it was suspended (not sleeping). */
+void
+srv_active_wake_master_thread_low()
+{
+	ut_ad(!srv_read_only_mode);
+	ut_ad(!srv_sys_mutex_own());
+
+	srv_inc_activity_count();
+
+	if (my_atomic_loadlint(&srv_sys.n_threads_active[SRV_MASTER]) == 0) {
+		srv_slot_t*	slot;
+
+		srv_sys_mutex_enter();
+
+		slot = &srv_sys.sys_threads[SRV_MASTER_SLOT];
+
+		/* Only if the master thread has been started. */
+
+		if (slot->in_use) {
+			ut_a(srv_slot_get_type(slot) == SRV_MASTER);
+			os_event_set(slot->event);
+		}
+
+		srv_sys_mutex_exit();
+	}
+}
+
 /** Wake up the purge threads if there is work to do. */
 void
 srv_wake_purge_thread_if_not_active()
@@ -1937,6 +1964,14 @@ srv_wake_purge_thread_if_not_active()
 	}
 }
 
+/** Wake up the master thread if it is suspended or being suspended. */
+void
+srv_wake_master_thread()
+{
+	srv_inc_activity_count();
+	srv_release_threads(SRV_MASTER, 1);
+}
+
 /*******************************************************************//**
 Get current server activity count. We don't hold srv_sys::mutex while
 reading this value as it is only used in heuristics.
@@ -1948,20 +1983,15 @@ srv_get_activity_count(void)
 	return(srv_sys.activity_count);
 }
 
-/** Check if there has been any activity.
-@param[in,out]  activity_count  recent activity count to be returned
-if there is a change
+/*******************************************************************//**
+Check if there has been any activity.
 @return FALSE if no change in activity counter. */
-bool srv_check_activity(ulint  *activity_count)
+ibool
+srv_check_activity(
+/*===============*/
+	ulint		old_activity_count)	/*!< in: old activity count */
 {
-  ulint new_activity_count= srv_sys.activity_count;
-  if (new_activity_count != *activity_count)
-  {
-    *activity_count= new_activity_count;
-    return true;
-  }
-
-  return false;
+	return(srv_sys.activity_count != old_activity_count);
 }
 
 /********************************************************************//**
@@ -2362,30 +2392,52 @@ DECLARE_THREAD(srv_master_thread)(
 	slot = srv_reserve_slot(SRV_MASTER);
 	ut_a(slot == srv_sys.sys_threads);
 
+loop:
 	while (srv_shutdown_state <= SRV_SHUTDOWN_INITIATED) {
 		srv_master_sleep();
 
 		MONITOR_INC(MONITOR_MASTER_THREAD_SLEEP);
 
-		if (srv_check_activity(&old_activity_count)) {
+		if (srv_check_activity(old_activity_count)) {
+			old_activity_count = srv_get_activity_count();
 			srv_master_do_active_tasks();
 		} else {
 			srv_master_do_idle_tasks();
 		}
 	}
 
-        ut_ad(srv_shutdown_state == SRV_SHUTDOWN_EXIT_THREADS
-              || srv_shutdown_state == SRV_SHUTDOWN_CLEANUP);
-
-	if (srv_shutdown_state == SRV_SHUTDOWN_CLEANUP
-            && srv_fast_shutdown < 2) {
-	        srv_shutdown(srv_fast_shutdown == 0);
+	switch (srv_shutdown_state) {
+	case SRV_SHUTDOWN_NONE:
+	case SRV_SHUTDOWN_INITIATED:
+		break;
+	case SRV_SHUTDOWN_FLUSH_PHASE:
+	case SRV_SHUTDOWN_LAST_PHASE:
+		ut_ad(0);
+		/* fall through */
+	case SRV_SHUTDOWN_EXIT_THREADS:
+		/* srv_init_abort() must have been invoked */
+	case SRV_SHUTDOWN_CLEANUP:
+		if (srv_shutdown_state == SRV_SHUTDOWN_CLEANUP
+		    && srv_fast_shutdown < 2) {
+			srv_shutdown(srv_fast_shutdown == 0);
+		}
+		srv_suspend_thread(slot);
+		my_thread_end();
+		os_thread_exit();
 	}
 
+	srv_main_thread_op_info = "suspending";
+
 	srv_suspend_thread(slot);
-	my_thread_end();
-	os_thread_exit();
-	OS_THREAD_DUMMY_RETURN;
+
+	/* DO NOT CHANGE THIS STRING. innobase_start_or_create_for_mysql()
+	waits for database activity to die down when converting < 4.1.x
+	databases, and relies on this string being exactly as it is. InnoDB
+	manual also mentions this string in several places. */
+	srv_main_thread_op_info = "waiting for server activity";
+
+	srv_resume_thread(slot);
+	goto loop;
 }
 
 /** @return whether purge should exit due to shutdown */
@@ -2553,13 +2605,15 @@ static ulint srv_do_purge(ulint* n_total_purged
 				++n_use_threads;
 			}
 
-		} else if (srv_check_activity(&old_activity_count)
+		} else if (srv_check_activity(old_activity_count)
 			   && n_use_threads > 1) {
 
 			/* History length same or smaller since last snapshot,
 			use fewer threads. */
 
 			--n_use_threads;
+
+			old_activity_count = srv_get_activity_count();
 		}
 
 		/* Ensure that the purge threads are less than what
diff --git a/storage/innobase/srv/srv0start.cc b/storage/innobase/srv/srv0start.cc
index 859e5a3eec2..318ab49cc9c 100644
--- a/storage/innobase/srv/srv0start.cc
+++ b/storage/innobase/srv/srv0start.cc
@@ -1178,7 +1178,7 @@ srv_shutdown_all_bg_threads()
 			if (srv_start_state_is_set(SRV_START_STATE_MASTER)) {
 				/* c. We wake the master thread so that
 				it exits */
-				srv_inc_activity_count();
+				srv_wake_master_thread();
 			}
 
 			if (srv_start_state_is_set(SRV_START_STATE_PURGE)) {
@@ -2526,7 +2526,7 @@ void srv_shutdown_bg_undo_sources()
 		fts_optimize_shutdown();
 		dict_stats_shutdown();
 		while (row_get_background_drop_list_len_low()) {
-			srv_inc_activity_count();
+			srv_wake_master_thread();
 			os_thread_yield();
 		}
 		srv_undo_sources = false;
diff --git a/storage/innobase/trx/trx0roll.cc b/storage/innobase/trx/trx0roll.cc
index c61a67ec05e..1be444adf07 100644
--- a/storage/innobase/trx/trx0roll.cc
+++ b/storage/innobase/trx/trx0roll.cc
@@ -164,6 +164,9 @@ trx_rollback_to_savepoint_low(
 
 	mem_heap_free(heap);
 
+	/* There might be work for utility threads.*/
+	srv_active_wake_master_thread();
+
 	MONITOR_DEC(MONITOR_TRX_ACTIVE);
 }
 
diff --git a/storage/innobase/trx/trx0trx.cc b/storage/innobase/trx/trx0trx.cc
index e1efc7c895f..1d4202b3033 100644
--- a/storage/innobase/trx/trx0trx.cc
+++ b/storage/innobase/trx/trx0trx.cc
@@ -1470,6 +1470,12 @@ trx_commit_in_memory(
 		}
 
 		trx->commit_lsn = lsn;
+
+		/* Tell server some activity has happened, since the trx
+		does changes something. Background utility threads like
+		master thread, purge thread or page_cleaner thread might
+		have some work to do. */
+		srv_active_wake_master_thread();
 	}
 
 	ut_ad(!trx->rsegs.m_noredo.undo);
diff --git a/unittest/mysys/CMakeLists.txt b/unittest/mysys/CMakeLists.txt
index ec4e0b91626..984b033e7aa 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
              byte_order
-             queues LINK_LIBRARIES mysys)
+             queues stacktrace LINK_LIBRARIES mysys)
 MY_ADD_TESTS(my_vsnprintf LINK_LIBRARIES strings mysys)
 MY_ADD_TESTS(aes LINK_LIBRARIES  mysys mysys_ssl)
 ADD_DEFINITIONS(${SSL_DEFINES})
diff --git a/unittest/mysys/stacktrace-t.c b/unittest/mysys/stacktrace-t.c
new file mode 100644
index 00000000000..8fa0db15b36
--- /dev/null
+++ b/unittest/mysys/stacktrace-t.c
@@ -0,0 +1,67 @@
+
+/* 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 Street, Fifth Floor, Boston, MA  02110-1335  USA */
+
+#include <my_global.h>
+#include <my_sys.h>
+#include <stdio.h>
+#include <my_stacktrace.h>
+#include <tap.h>
+
+char b_bss[10];
+
+void test_my_safe_print_str()
+{
+  char b_stack[10];
+  char *b_heap= strdup("LEGAL");
+  memcpy(b_stack, "LEGAL", 6);
+  memcpy(b_bss, "LEGAL", 6);
+
+#ifndef __SANITIZE_ADDRESS__
+  fprintf(stderr, "\n===== stack =====\n");
+  my_safe_print_str(b_stack, 65535);
+  fprintf(stderr, "\n===== heap =====\n");
+  my_safe_print_str(b_heap, 65535);
+  fprintf(stderr, "\n===== BSS =====\n");
+  my_safe_print_str(b_bss, 65535);
+  fprintf(stderr, "\n===== data =====\n");
+  my_safe_print_str("LEGAL", 65535);
+  fprintf(stderr, "\n===== Above is a junk, but it is expected. =====\n");
+#endif /*__SANITIZE_ADDRESS__*/
+  fprintf(stderr, "\n===== Nornal length test =====\n");
+  my_safe_print_str("LEGAL", 5);
+  fprintf(stderr, "\n===== NULL =====\n");
+  my_safe_print_str(0, 5);
+#ifndef __SANITIZE_ADDRESS__
+  fprintf(stderr, "\n===== (const char*) 1 =====\n");
+  my_safe_print_str((const char*)1, 5);
+#endif /*__SANITIZE_ADDRESS__*/
+
+  free(b_heap);
+
+  ok(1, "test_my_safe_print_str");
+}
+
+
+int main(int argc __attribute__((unused)), char **argv)
+{
+  MY_INIT(argv[0]);
+  plan(1);
+
+  test_my_safe_print_str();
+
+  my_end(0);
+  return exit_status();
+}