Merge branch '10.6.12' into 10.6

VERSION

 MYSQL_VERSION_MAJOR=10
 MYSQL_VERSION_MINOR=6
-MYSQL_VERSION_PATCH=12
+MYSQL_VERSION_PATCH=13
 SERVER_MATURITY=stable

dbug/dbug.c

@@ -86,7 +86,7 @@
 #include <m_string.h>
 #include <errno.h>
 #ifdef HAVE_gcov
-extern void __gcov_flush();
+#include <gcov.h>
 #endif
 
 #ifndef DBUG_OFF
@@ -2212,7 +2212,7 @@ void _db_suicide_()
   fprintf(stderr, "SIGKILL myself\n");
   fflush(stderr);
 #ifdef HAVE_gcov
-  __gcov_flush();
+  __gcov_dump();
 #endif
 
   retval= kill(getpid(), SIGKILL);
@@ -2262,7 +2262,7 @@ my_bool _db_my_assert(const char *file, int line, const char *msg)
     fprintf(stderr, "%s:%d: assert: %s\n", file, line, msg);
     fflush(stderr);
 #ifdef HAVE_gcov
-    __gcov_flush();
+    __gcov_dump();
 #endif
   }
   return a;

mysql-test/main/debug_sync.result

@@ -2,7 +2,7 @@ SET DEBUG_SYNC= 'RESET';
 DROP TABLE IF EXISTS t1;
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: ''
+debug_sync	ON - current signals: ''
 SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2 HIT_LIMIT 3';
 SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6 EXECUTE 2';
 SET DEBUG_SYNC='p0 SIGNAL s1 WAIT_FOR s2 TIMEOUT 6           HIT_LIMIT 3';
@@ -150,34 +150,34 @@ SET @myvar= 'now SIGNAL from_myvar';
 SET DEBUG_SYNC= @myvar;
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 'from_myvar'
+debug_sync	ON - current signals: 'from_myvar'
 SET DEBUG_SYNC= LEFT('now SIGNAL from_function_cut_here', 24);
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 'from_function'
+debug_sync	ON - current signals: 'from_myvar,from_function'
 SET DEBUG_SYNC= 'now SIGNAL something';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 'something'
+debug_sync	ON - current signals: 'something,from_function,from_myvar'
 SET DEBUG_SYNC= 'now WAIT_FOR nothing TIMEOUT 0';
 Warnings:
 Warning	####	debug sync point wait timed out
 SET DEBUG_SYNC= 'now SIGNAL nothing';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 'nothing'
+debug_sync	ON - current signals: 'something,from_function,nothing,from_myvar'
 SET DEBUG_SYNC= 'now WAIT_FOR nothing TIMEOUT 0';
 SET DEBUG_SYNC= 'now SIGNAL something EXECUTE 0';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 'nothing'
+debug_sync	ON - current signals: 'something,from_function,from_myvar'
 SET DEBUG_SYNC= 'now WAIT_FOR anotherthing TIMEOUT 0 EXECUTE 0';
 SET DEBUG_SYNC= 'now HIT_LIMIT 1';
 ERROR HY000: debug sync point hit limit reached
 SET DEBUG_SYNC= 'RESET';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: ''
+debug_sync	ON - current signals: ''
 SET DEBUG_SYNC= 'p1abcd   SIGNAL s1 EXECUTE 2';
 SET DEBUG_SYNC= 'p2abc    SIGNAL s2 EXECUTE 2';
 SET DEBUG_SYNC= 'p9abcdef SIGNAL s9 EXECUTE 2';
@@ -190,23 +190,30 @@ SET DEBUG_SYNC= 'p3abcdef SIGNAL s3 EXECUTE 2';
 SET DEBUG_SYNC= 'p4a      TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's4'
+debug_sync	ON - current signals: 's4'
 SET DEBUG_SYNC= 'p1abcd   TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's1'
+debug_sync	ON - current signals: 's4,s1'
 SET DEBUG_SYNC= 'p7       TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's7'
+debug_sync	ON - current signals: 's1,s7,s4'
 SET DEBUG_SYNC= 'p9abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's9'
+debug_sync	ON - current signals: 's1,s7,s4,s9'
 SET DEBUG_SYNC= 'p3abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's3'
+debug_sync	ON - current signals: 's1,s3,s4,s9,s7'
+SET DEBUG_SYNC= 'now WAIT_FOR s9';
+SET DEBUG_SYNC= 'now WAIT_FOR s1';
+SET DEBUG_SYNC= 'now WAIT_FOR s4';
+SET DEBUG_SYNC= 'now WAIT_FOR s7';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+Variable_name	Value
+debug_sync	ON - current signals: 's3'
 SET DEBUG_SYNC= 'p1abcd   CLEAR';
 SET DEBUG_SYNC= 'p2abc    CLEAR';
 SET DEBUG_SYNC= 'p5abcde  CLEAR';
@@ -219,19 +226,19 @@ SET DEBUG_SYNC= 'p7       CLEAR';
 SET DEBUG_SYNC= 'p1abcd   TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's3'
+debug_sync	ON - current signals: 's3'
 SET DEBUG_SYNC= 'p7       TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's3'
+debug_sync	ON - current signals: 's3'
 SET DEBUG_SYNC= 'p9abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: 's3'
+debug_sync	ON - current signals: 's3'
 SET DEBUG_SYNC= 'RESET';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 Variable_name	Value
-debug_sync	ON - current signal: ''
+debug_sync	ON - current signals: ''
 CREATE USER mysqltest_1@localhost;
 GRANT SUPER ON *.* TO mysqltest_1@localhost;
 connect  con1,localhost,mysqltest_1,,;
@@ -292,4 +299,24 @@ disconnect con1;
 disconnect con2;
 connection default;
 DROP TABLE t1;
+#
+# Test NO_CLEAR_EVENT flag. The signal should still be visible after
+# the wait has completed succesfully.
+#
+SET DEBUG_SYNC= 'now SIGNAL s1';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+Variable_name	Value
+debug_sync	ON - current signals: 's1'
+SET DEBUG_SYNC= 'now WAIT_FOR s1 NO_CLEAR_EVENT';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+Variable_name	Value
+debug_sync	ON - current signals: 's1'
+SET DEBUG_SYNC= 'now WAIT_FOR s1';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+Variable_name	Value
+debug_sync	ON - current signals: ''
+SET DEBUG_SYNC= 'now SIGNAL s1,s2,s5,s7';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+Variable_name	Value
+debug_sync	ON - current signals: 's2,s7,s1,s5'
 SET DEBUG_SYNC= 'RESET';

mysql-test/main/debug_sync.test

@@ -298,6 +298,16 @@ SET DEBUG_SYNC= 'p9abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 SET DEBUG_SYNC= 'p3abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
+
+#
+# Wait for all signals currently active except s3.
+#
+SET DEBUG_SYNC= 'now WAIT_FOR s9';
+SET DEBUG_SYNC= 'now WAIT_FOR s1';
+SET DEBUG_SYNC= 'now WAIT_FOR s4';
+SET DEBUG_SYNC= 'now WAIT_FOR s7';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+
 #
 # Clear the actions.
 #
@@ -320,7 +330,7 @@ SHOW VARIABLES LIKE 'DEBUG_SYNC';
 SET DEBUG_SYNC= 'p9abcdef TEST';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
 #
-# Now cleanup. Actions are clear already, but signal needs to be cleared.
+# Now cleanup. Actions are clear already, but s3 signal needs to be cleared.
 #
 SET DEBUG_SYNC= 'RESET';
 SHOW VARIABLES LIKE 'DEBUG_SYNC';
@@ -418,10 +428,24 @@ disconnect con2;
 connection default;
 DROP TABLE t1;
 
+--echo #
+--echo # Test NO_CLEAR_EVENT flag. The signal should still be visible after
+--echo # the wait has completed succesfully.
+--echo #
+SET DEBUG_SYNC= 'now SIGNAL s1';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+SET DEBUG_SYNC= 'now WAIT_FOR s1 NO_CLEAR_EVENT';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+SET DEBUG_SYNC= 'now WAIT_FOR s1';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+
+SET DEBUG_SYNC= 'now SIGNAL s1,s2,s5,s7';
+SHOW VARIABLES LIKE 'DEBUG_SYNC';
+
+
 #
 # Cleanup after test case.
-# Otherwise signal would contain 'flushed' here,
-# which could confuse the next test.
+# Otherwise signal would confuse the next test.
 #
 SET DEBUG_SYNC= 'RESET';
 

mysql-test/mariadb-test-run.pl

@@ -145,6 +145,7 @@ my $opt_start_exit;
 my $start_only;
 my $file_wsrep_provider;
 my $num_saved_cores= 0;  # Number of core files saved in vardir/log/ so far.
+my $test_name_for_report;
 
 our @global_suppressions;
 
@@ -515,13 +516,13 @@ sub main {
   }
 
   if ( not @$completed ) {
-    my $test_name= mtr_grab_file($path_testlog);
-    $test_name =~ s/^CURRENT_TEST:\s//;
-    chomp($test_name);
-    my $tinfo = My::Test->new(name => $test_name);
+    if ($test_name_for_report)
+    {
+      my $tinfo = My::Test->new(name => $test_name_for_report);
       $tinfo->{result}= 'MTR_RES_FAILED';
       $tinfo->{comment}=' ';
       mtr_report_test($tinfo);
+    }
     mtr_error("Test suite aborted");
   }
 
@@ -3740,8 +3741,8 @@ sub resfile_report_test ($) {
 sub run_testcase ($$) {
   my ($tinfo, $server_socket)= @_;
   my $print_freq=20;
-
-  mtr_verbose("Running test:", $tinfo->{name});
+  $test_name_for_report= $tinfo->{name};
+  mtr_verbose("Running test:", $test_name_for_report);
   $ENV{'MTR_TEST_NAME'} = $tinfo->{name};
   resfile_report_test($tinfo) if $opt_resfile;
 
@@ -5130,12 +5131,10 @@ sub mysqld_start ($$) {
   if (!$rc)
   {
     # Report failure about the last test case before exit
-    my $test_name= mtr_grab_file($path_current_testlog);
-    $test_name =~ s/^CURRENT_TEST:\s//;
-    my $tinfo = My::Test->new(name => $test_name);
+    my $tinfo = My::Test->new(name => $test_name_for_report);
     $tinfo->{result}= 'MTR_RES_FAILED';
     $tinfo->{failures}= 1;
-    $tinfo->{logfile}=get_log_from_proc($mysqld->{'proc'}, $tinfo->{name});
+    $tinfo->{logfile}=get_log_from_proc($mysqld->{'proc'}, $test_name_for_report);
     report_option('verbose', 1);
     mtr_report_test($tinfo);
   }

mysql-test/suite/innodb/r/mdev-14846.result

@@ -31,11 +31,12 @@ pk	f1	f2	f3
 3	t	q	1
 5	z	t	NULL
 SET DEBUG_SYNC='now SIGNAL default_dml';
+SET DEBUG_SYNC='now SIGNAL con2_dml';
 connection default;
 SET DEBUG_SYNC='now WAIT_FOR default_dml';
 UPDATE t3 AS alias1 LEFT JOIN t3 AS alias2 ON ( alias1.f1 <> alias1.f2 ) SET alias1.f3 = 59 WHERE ( EXISTS ( SELECT t1.f3 FROM t1 WHERE t1.f1 = alias1.f1 ) ) OR alias2.f1 = 'h';
 connect  con2,localhost,root,,test;
-set debug_sync='now WAIT_FOR default_dml';
+set debug_sync='now WAIT_FOR con2_dml';
 SET DEBUG_SYNC='now SIGNAL con1_dml2';
 disconnect con2;
 connection con1;

mysql-test/suite/innodb/t/mdev-14846.test

@@ -35,6 +35,7 @@ SET DEBUG_SYNC='now WAIT_FOR con1_dml';
 begin;
 SELECT * FROM t1 for update; # Holds x lock of all records in the table t1
 SET DEBUG_SYNC='now SIGNAL default_dml';
+SET DEBUG_SYNC='now SIGNAL con2_dml';
 
 --connection default
 SET DEBUG_SYNC='now WAIT_FOR default_dml';
@@ -42,7 +43,7 @@ SET DEBUG_SYNC='now WAIT_FOR default_dml';
 # It holds the lock of all record in t3 and tries to acquire record lock for the table  t1.
 
 --connect (con2,localhost,root,,test)
-set debug_sync='now WAIT_FOR default_dml';
+set debug_sync='now WAIT_FOR con2_dml';
 let $wait_condition=
 select count(*) > 0 from information_schema.innodb_lock_waits;
 --source include/wait_condition.inc

mysql-test/suite/stress/r/deadlock_drop_table.result

@@ -19,11 +19,12 @@ a	b	c
 1	NULL	NULL
 set debug_sync='now SIGNAL go';
 set debug_sync='now WAIT_FOR parked2';
-set debug_sync='before_wait_for_refs SIGNAL waiting WAIT_FOR go2';
+set debug_sync='before_wait_for_refs SIGNAL waiting WAIT_FOR go3';
 drop table t1;;
 connection con2;
 set debug_sync='now WAIT_FOR waiting';
 set debug_sync='now SIGNAL go2';
+set debug_sync='now SIGNAL go3';
 connection default;
 connection con1;
 connection default;

mysql-test/suite/stress/t/deadlock_drop_table.test

@@ -20,15 +20,12 @@ set debug_sync='now WAIT_FOR parked';
 select * from t1;
 set debug_sync='now SIGNAL go';
 set debug_sync='now WAIT_FOR parked2';
-set debug_sync='before_wait_for_refs SIGNAL waiting WAIT_FOR go2';
+set debug_sync='before_wait_for_refs SIGNAL waiting WAIT_FOR go3';
 --send drop table t1;
 --connection con2
 set debug_sync='now WAIT_FOR waiting';
 set debug_sync='now SIGNAL go2';
-
-# Write out show processlist if the debug sync point times out
-let $wait_condition= select count(*)=0 from information_schema.processlist where state like "%debug%";
-source include/wait_condition.inc;
+set debug_sync='now SIGNAL go3';
 
 --connection default
 --reap

mysql-test/suite/sys_vars/r/debug_sync_basic.result

@@ -2,17 +2,17 @@ select @@global.debug_sync;
 ERROR HY000: Variable 'debug_sync' is a SESSION variable
 select @@session.debug_sync;
 @@session.debug_sync
-ON - current signal: ''
+ON - current signals: ''
 show global variables like "debug_sync";
 Variable_name	Value
 show session variables like "debug_sync";
 Variable_name	Value
-debug_sync	ON - current signal: ''
+debug_sync	ON - current signals: ''
 select * from information_schema.global_variables where variable_name="debug_sync";
 VARIABLE_NAME	VARIABLE_VALUE
 select * from information_schema.session_variables where variable_name="debug_sync";
 VARIABLE_NAME	VARIABLE_VALUE
-DEBUG_SYNC	ON - current signal: ''
+DEBUG_SYNC	ON - current signals: ''
 set @@session.debug_sync=1;
 ERROR 42000: Incorrect argument type to variable 'debug_sync'
 set @@session.debug_sync=1.1;

mysql-test/suite/sys_vars/r/sysvars_debug.result

@@ -77,7 +77,7 @@ READ_ONLY	YES
 COMMAND_LINE_ARGUMENT	OPTIONAL
 GLOBAL_VALUE_PATH	NULL
 VARIABLE_NAME	DEBUG_SYNC
-SESSION_VALUE	ON - current signal: ''
+SESSION_VALUE	ON - current signals: ''
 GLOBAL_VALUE	NULL
 GLOBAL_VALUE_ORIGIN	COMPILE-TIME
 DEFAULT_VALUE	

mysys/stacktrace.c

@@ -34,6 +34,9 @@
 #include <execinfo.h>
 #endif
 
+#ifdef HAVE_gcov
+#include <gcov.h>
+#endif
 /**
    Default handler for printing stacktrace
 */
@@ -409,9 +412,6 @@ void my_print_stacktrace(uchar* stack_bottom, ulong thread_stack,
 /* Produce a core for the thread */
 void my_write_core(int sig)
 {
-#ifdef HAVE_gcov
-  extern void __gcov_flush(void);
-#endif
   signal(sig, SIG_DFL);
 #ifdef HAVE_gcov
   /*
@@ -419,7 +419,7 @@ void my_write_core(int sig)
     information from this process, causing gcov output to be incomplete.
     So we force the writing of coverage information here before terminating.
   */
-  __gcov_flush();
+  __gcov_dump();
 #endif
   pthread_kill(pthread_self(), sig);
 #if defined(P_MYID) && !defined(SCO)

sql/debug_sync.cc

@@ -18,6 +18,7 @@
 
 #include "mariadb.h"
 #include "debug_sync.h"
+#include <cstring>
 
 #if defined(ENABLED_DEBUG_SYNC)
 
@@ -48,6 +49,8 @@ struct st_debug_sync_action
   String        wait_for;               /* signal to wait for */
   String        sync_point;             /* sync point name */
   bool          need_sort;              /* if new action, array needs sort */
+  bool          clear_event;            /* do not clear signal when waited
+                                           for if false. */
 };
 
 /* Debug sync control. Referenced by THD. */
@@ -67,21 +70,99 @@ struct st_debug_sync_control
 };
 
 
+
+
 /**
   Definitions for the debug sync facility.
-  1. Global string variable to hold a "signal" ("signal post", "flag mast").
+  1. Global string variable to hold a set of of "signals".
   2. Global condition variable for signaling and waiting.
   3. Global mutex to synchronize access to the above.
 */
 struct st_debug_sync_globals
 {
-  String                ds_signal;              /* signal variable */
+  Hash_set<LEX_CSTRING> ds_signal_set;          /* A set of active signals */
   mysql_cond_t          ds_cond;                /* condition variable */
   mysql_mutex_t         ds_mutex;               /* mutex variable */
   ulonglong             dsp_hits;               /* statistics */
   ulonglong             dsp_executed;           /* statistics */
   ulonglong             dsp_max_active;         /* statistics */
+
+  st_debug_sync_globals() : ds_signal_set(PSI_NOT_INSTRUMENTED, signal_key) {};
+  ~st_debug_sync_globals()
+  {
+    clear_set();
+  }
+
+  void clear_set()
+  {
+    Hash_set<LEX_CSTRING>::Iterator it{ds_signal_set};
+    LEX_CSTRING *s;
+    while ((s= it++))
+      my_free(s);
+    ds_signal_set.clear();
+  }
+
+  /* Hash key function for ds_signal_set. */
+  static uchar *signal_key(const LEX_CSTRING *str, size_t *klen, my_bool)
+  {
+    *klen= str->length;
+    return (uchar*) str->str;
+  }
+
+  /**
+    Return true if the signal is found in global signal list.
+
+    @param signal_name Signal name identifying the signal.
+
+    @note
+      If signal is found in the global signal set, it means that the
+      signal thread has signalled to the waiting thread. This method
+      must be called with the debug_sync_global.ds_mutex held.
+
+    @retval true  if signal is found in the global signal list.
+    @retval false otherwise.
+  */
+
+  inline bool is_signalled(const char *signal_name, size_t length)
+  {
+    return ds_signal_set.find(signal_name, length);
+  }
+
+  void clear_signal(const String &signal_name)
+  {
+    DBUG_ENTER("clear_signal");
+    LEX_CSTRING *record= ds_signal_set.find(signal_name.ptr(),
+                                            signal_name.length());
+    if (record)
+    {
+      ds_signal_set.remove(record);
+      my_free(record);
+    }
+    DBUG_VOID_RETURN;
+  }
+
+  bool set_signal(const char *signal_name, size_t length)
+  {
+    /* Need to check if the signal is already in the hash set, because
+       Hash_set doesn't differentiate between OOM and key already in. */
+    if (is_signalled(signal_name, length))
+      return FALSE;
+    /* LEX_CSTRING and the string allocated with only one malloc. */
+    LEX_CSTRING *s= (LEX_CSTRING *) my_malloc(PSI_NOT_INSTRUMENTED,
+                                              sizeof(LEX_CSTRING) + length + 1,
+                                              MYF(0));
+    char *str= (char *)(s + 1);
+    memcpy(str, signal_name, length);
+    str[length]= '\0';
+
+    s->length= length;
+    s->str= str;
+    if (ds_signal_set.insert(s))
+      return TRUE;
+    return FALSE;
+  }
 };
+
 static st_debug_sync_globals debug_sync_global; /* All globals in one object */
 
 /**
@@ -161,7 +242,7 @@ int debug_sync_init(void)
     int rc;
 
     /* Initialize the global variables. */
-    debug_sync_global.ds_signal.length(0);
+    debug_sync_global.clear_set();
     if ((rc= mysql_cond_init(key_debug_sync_globals_ds_cond,
                              &debug_sync_global.ds_cond, NULL)) ||
         (rc= mysql_mutex_init(key_debug_sync_globals_ds_mutex,
@@ -195,7 +276,7 @@ void debug_sync_end(void)
     debug_sync_C_callback_ptr= NULL;
 
     /* Destroy the global variables. */
-    debug_sync_global.ds_signal.free();
+    debug_sync_global.clear_set();
     mysql_cond_destroy(&debug_sync_global.ds_cond);
     mysql_mutex_destroy(&debug_sync_global.ds_mutex);
 
@@ -271,6 +352,40 @@ void debug_sync_init_thread(THD *thd)
 }
 
 
+/**
+  Returns an allocated buffer containing a comma-separated C string of all
+  active signals.
+
+  Buffer must be freed by the caller.
+*/
+static const char *get_signal_set_as_string()
+{
+  mysql_mutex_assert_owner(&debug_sync_global.ds_mutex);
+  size_t req_size= 1; // In case of empty set for the end '\0' char.
+
+  for (size_t i= 0; i < debug_sync_global.ds_signal_set.size(); i++)
+    req_size+= debug_sync_global.ds_signal_set.at(i)->length + 1;
+
+  char *buf= (char *) my_malloc(PSI_NOT_INSTRUMENTED, req_size, MYF(0));
+  if (!buf)
+    return nullptr;
+  memset(buf, '\0', req_size);
+
+  char *cur_pos= buf;
+  for (size_t i= 0; i < debug_sync_global.ds_signal_set.size(); i++)
+  {
+    const LEX_CSTRING *signal= debug_sync_global.ds_signal_set.at(i);
+    memcpy(cur_pos, signal->str, signal->length);
+    if (i != debug_sync_global.ds_signal_set.size() - 1)
+      cur_pos[signal->length]= ',';
+    else
+      cur_pos[signal->length] = '\0';
+    cur_pos+= signal->length + 1;
+  }
+  return buf;
+}
+
+
 /**
   End the debug sync facility at thread end.
 
@@ -554,7 +669,7 @@ static void debug_sync_reset(THD *thd)
 
   /* Clear the global signal. */
   mysql_mutex_lock(&debug_sync_global.ds_mutex);
-  debug_sync_global.ds_signal.length(0);
+  debug_sync_global.clear_set();
   mysql_mutex_unlock(&debug_sync_global.ds_mutex);
 
   DBUG_VOID_RETURN;
@@ -1175,6 +1290,7 @@ static bool debug_sync_eval_action(THD *thd, char *action_str, char *action_end)
     /* Set default for EXECUTE and TIMEOUT options. */
     action->execute= 1;
     action->timeout= opt_debug_sync_timeout;
+    action->clear_event= true;
 
     /* Get next token. If none follows, set action. */
     if (!(ptr= debug_sync_token(&token, &token_length, ptr, action_end)))
@@ -1225,6 +1341,15 @@ static bool debug_sync_eval_action(THD *thd, char *action_str, char *action_end)
       goto set_action;
   }
 
+  /*
+    Try NO_CLEAR_EVENT.
+  */
+  if (!my_strcasecmp(system_charset_info, token, "NO_CLEAR_EVENT")) {
+    action->clear_event= false;
+    /* Get next token. If none follows, set action. */
+    if (!(ptr = debug_sync_token(&token, &token_length, ptr, action_end))) goto set_action;
+  }
+
   /*
     Try HIT_LIMIT.
   */
@@ -1325,13 +1450,19 @@ uchar *debug_sync_value_ptr(THD *thd)
 
   if (opt_debug_sync_timeout)
   {
-    static char on[]= "ON - current signal: '"; 
+    static char on[]= "ON - current signals: '";
 
     // Ensure exclusive access to debug_sync_global.ds_signal
     mysql_mutex_lock(&debug_sync_global.ds_mutex);
 
-    size_t lgt= (sizeof(on) /* includes '\0' */ +
-                 debug_sync_global.ds_signal.length() + 1 /* for '\'' */);
+    size_t lgt= sizeof(on) + 1; /* +1 as we'll have to append ' at the end. */
+
+    for (size_t i= 0; i < debug_sync_global.ds_signal_set.size(); i++)
+    {
+      /* Assume each signal is separated by a comma, hence +1. */
+      lgt+= debug_sync_global.ds_signal_set.at(i)->length + 1;
+    }
+
     char *vend;
     char *vptr;
 
@@ -1339,9 +1470,14 @@ uchar *debug_sync_value_ptr(THD *thd)
     {
       vend= value + lgt - 1; /* reserve space for '\0'. */
       vptr= debug_sync_bmove_len(value, vend, STRING_WITH_LEN(on));
-      vptr= debug_sync_bmove_len(vptr, vend, debug_sync_global.ds_signal.ptr(),
-                                 debug_sync_global.ds_signal.length());
-      if (vptr < vend)
+      for (size_t i= 0; i < debug_sync_global.ds_signal_set.size(); i++)
+      {
+        const LEX_CSTRING *s= debug_sync_global.ds_signal_set.at(i);
+        vptr= debug_sync_bmove_len(vptr, vend, s->str, s->length);
+        if (i != debug_sync_global.ds_signal_set.size() - 1)
+          *(vptr++)= ',';
+      }
+      DBUG_ASSERT(vptr < vend);
       *(vptr++)= '\'';
       *vptr= '\0'; /* We have one byte reserved for the worst case. */
     }
@@ -1358,6 +1494,9 @@ uchar *debug_sync_value_ptr(THD *thd)
 }
 
 
+
+
+
 /**
   Execute requested action at a synchronization point.
 
@@ -1413,12 +1552,28 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
       read access too, to create a memory barrier in order to avoid that
       threads just reads an old cached version of the signal.
     */
+
     mysql_mutex_lock(&debug_sync_global.ds_mutex);
 
     if (action->signal.length())
     {
-      /* Copy the signal to the global variable. */
-      if (debug_sync_global.ds_signal.copy(action->signal))
+      int offset= 0, pos;
+      bool error= false;
+
+      /* This loop covers all signals in the list except for the last one.
+         Split the signal string by commas and set a signal in the global
+         variable for each one. */
+      while (!error && (pos= action->signal.strstr(",", 1, offset)) > 0)
+      {
+        error= debug_sync_global.set_signal(action->signal.ptr() + offset,
+                                            pos - offset);
+        offset= pos + 1;
+      }
+
+      if (error ||
+          /* The last signal in the list. */
+          debug_sync_global.set_signal(action->signal.ptr() + offset,
+                                       action->signal.length() - offset))
       {
         /*
           Error is reported by my_malloc().
@@ -1461,12 +1616,22 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
         restore_current_mutex = false;
 
       set_timespec(abstime, action->timeout);
-      DBUG_EXECUTE("debug_sync_exec",
+      DBUG_EXECUTE("debug_sync_exec", {
+          const char *signal_set= get_signal_set_as_string();
+          if (!signal_set)
+          {
+            DBUG_PRINT("debug_sync_exec",
+                       ("Out of memory when fetching signal set"));
+          }
+          else
+          {
             /* Functions as DBUG_PRINT args can change keyword and line nr. */
             DBUG_PRINT("debug_sync_exec",
-                     ("wait for '%s'  at: '%s'  curr: '%s'",
-                      sig_wait, dsp_name,
-                      debug_sync_global.ds_signal.c_ptr())););
+                       ("wait for '%s'  at: '%s', curr: '%s'",
+                        sig_wait, dsp_name, signal_set));
+            my_free((void *)signal_set);
+          }});
+
 
       /*
         Wait until global signal string matches the wait_for string.
@@ -1474,18 +1639,20 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
         The facility can become disabled when some thread cannot get
         the required dynamic memory allocated.
       */
-      while (stringcmp(&debug_sync_global.ds_signal, &action->wait_for) &&
-             !(thd->killed & KILL_HARD_BIT) && opt_debug_sync_timeout)
+      while (!debug_sync_global.is_signalled(action->wait_for.ptr(),
+                                             action->wait_for.length()) &&
+             !(thd->killed & KILL_HARD_BIT) &&
+             opt_debug_sync_timeout)
       {
         error= mysql_cond_timedwait(&debug_sync_global.ds_cond,
                                     &debug_sync_global.ds_mutex,
                                     &abstime);
-        DBUG_EXECUTE("debug_sync",
+        // TODO turn this into a for loop printing.
+        DBUG_EXECUTE("debug_sync", {
             /* Functions as DBUG_PRINT args can change keyword and line nr. */
             DBUG_PRINT("debug_sync",
-                       ("awoke from %s  global: %s  error: %d",
-                        sig_wait, debug_sync_global.ds_signal.c_ptr(),
-                        error)););
+                       ("awoke from %s error: %d",
+                        sig_wait, error));});
         if (unlikely(error == ETIMEDOUT || error == ETIME))
         {
           // We should not make the statement fail, even if in strict mode.
@@ -1498,6 +1665,10 @@ static void debug_sync_execute(THD *thd, st_debug_sync_action *action)
         }
         error= 0;
       }
+
+      if (action->clear_event)
+        debug_sync_global.clear_signal(action->wait_for);
+
       DBUG_EXECUTE("debug_sync_exec",
                    if (thd->killed)
                      DBUG_PRINT("debug_sync_exec",
@@ -1571,10 +1742,10 @@ static void debug_sync(THD *thd, const char *sync_point_name, size_t name_len)
   st_debug_sync_control *ds_control= thd->debug_sync_control;
   st_debug_sync_action  *action;
   DBUG_ENTER("debug_sync");
+  DBUG_PRINT("debug_sync_point", ("hit: '%s'", sync_point_name));
   DBUG_ASSERT(sync_point_name);
   DBUG_ASSERT(name_len);
   DBUG_ASSERT(ds_control);
-  DBUG_PRINT("debug_sync_point", ("hit: '%s'", sync_point_name));
 
   /* Statistics. */
   ds_control->dsp_hits++;

sql/sql_hset.h

@@ -15,6 +15,7 @@
    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 "hash.h"
 
 
@@ -28,20 +29,18 @@ class Hash_set
 public:
   enum { START_SIZE= 8 };
   /**
-    Constructs an empty hash. Does not allocate memory, it is done upon
-    the first insert. Thus does not cause or return errors.
+    Constructs an empty unique hash.
   */
   Hash_set(PSI_memory_key psi_key, uchar *(*K)(const T *, size_t *, my_bool),
            CHARSET_INFO *cs= &my_charset_bin)
   {
-    my_hash_clear(&m_hash);
-    m_hash.get_key= (my_hash_get_key)K;
-    m_hash.charset= cs;
-    m_hash.array.m_psi_key= psi_key;
+    my_hash_init(psi_key, &m_hash, cs, START_SIZE, 0, 0, (my_hash_get_key)K, 0,
+                 HASH_UNIQUE);
   }
+
   Hash_set(PSI_memory_key psi_key, CHARSET_INFO *charset, ulong default_array_elements,
            size_t key_offset, size_t key_length, my_hash_get_key get_key,
-           void (*free_element)(void*), uint flags)
+           void (*free_element)(void*),uint flags)
   {
     my_hash_init(psi_key, &m_hash, charset, default_array_elements, key_offset,
                  key_length, get_key, free_element, flags);
@@ -65,8 +64,6 @@ class Hash_set
   */
   bool insert(T *value)
   {
-    my_hash_init_opt(m_hash.array.m_psi_key, &m_hash, m_hash.charset,
-                     START_SIZE, 0, 0, m_hash.get_key, 0, HASH_UNIQUE);
     return my_hash_insert(&m_hash, reinterpret_cast<const uchar*>(value));
   }
   bool remove(T *value)

sql/sql_string.cc

@@ -677,24 +677,23 @@ bool String::append_with_prefill(const char *s,uint32 arg_length,
 }
 
 
-int Binary_string::strstr(const Binary_string &s, uint32 offset)
+int Binary_string::strstr(const char *search, uint32 search_length, uint32 offset)
 {
-  if (s.length()+offset <= str_length)
+  if (search_length + offset <= str_length)
   {
-    if (!s.length())
+    if (!search_length)
       return ((int) offset);	// Empty string is always found
 
-    const char *str = Ptr+offset;
-    const char *search=s.ptr();
-    const char *end=Ptr+str_length-s.length()+1;
-    const char *search_end=s.ptr()+s.length();
+    const char *str= Ptr + offset;
+    const char *end= Ptr + str_length - search_length + 1;
+    const char *search_end= search + search_length;
 skip:
     while (str != end)
     {
       if (*str++ == *search)
       {
-	char *i,*j;
-	i=(char*) str; j=(char*) search+1;
+        char *i= (char*) str;
+        char *j= (char*) search + 1 ;
         while (j != search_end)
           if (*i++ != *j++) goto skip;
         return (int) (str-Ptr) -1;
@@ -704,6 +703,11 @@ int Binary_string::strstr(const Binary_string &s, uint32 offset)
   return -1;
 }
 
+int Binary_string::strstr(const Binary_string &s, uint32 offset)
+{
+  return strstr(s.ptr(), s.length(), offset);
+}
+
 /*
 ** Search string from end. Offset is offset to the end of string
 */

sql/sql_string.h

@@ -330,6 +330,7 @@ class Binary_string: public Sql_alloc
 
   // Returns offset to substring or -1
   int strstr(const Binary_string &search, uint32 offset=0);
+  int strstr(const char *search, uint32 search_length, uint32 offset=0);
   // Returns offset to substring or -1
   int strrstr(const Binary_string &search, uint32 offset=0);
 

storage/connect/bsonudf.cpp

@@ -3571,7 +3571,7 @@ char *bson_item_merge(UDF_INIT *initid, UDF_ARGS *args, char *result,
 	} // endif Xchk
 
 	if (!CheckMemory(g, initid, args, 2, false, false, true)) {
-		JTYP  type;
+		JTYP  type= TYPE_JAR;
 		BJNX  bnx(g);
 		PBVAL jvp = NULL, top = NULL;
 		PBVAL jsp[2] = {NULL, NULL};
@@ -5724,7 +5724,7 @@ char *bbin_item_merge(UDF_INIT *initid, UDF_ARGS *args, char *result,
 	} // endif Xchk
 
 	if (!CheckMemory(g, initid, args, 2, false, false, true)) {
-		JTYP  type;
+		JTYP  type = TYPE_JAR;
 		BJNX  bnx(g);
 		PBVAL jvp = NULL, top = NULL;
 		PBVAL jsp[2] = {NULL, NULL};