Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1619 insertions, 0 deletions

diff --git a/sql/event_data_objects.cc b/sql/event_data_objects.cc
new file mode 100644
index 00000000..bb552aa9
--- /dev/null
+++ b/sql/event_data_objects.cc
@@ -0,0 +1,1619 @@
+/*
+   Copyright (c) 2005, 2010, Oracle and/or its affiliates.
+
+   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 */
+
+#define MYSQL_LEX 1
+#include "mariadb.h"                          /* NO_EMBEDDED_ACCESS_CHECKS */
+#include "sql_priv.h"
+#include "unireg.h"
+#include "sql_parse.h"                          // parse_sql
+#include "strfunc.h"                           // find_string_in_array
+#include "sql_db.h"                        // get_default_db_collation
+#include "sql_time.h"                      // interval_type_to_name,
+                                           // date_add_interval,
+                                           // calc_time_diff
+#include "tztime.h"     // my_tz_find, my_tz_OFFSET0, struct Time_zone
+#include "sp.h"         // load_charset, load_collation
+#include "events.h"
+#include "event_data_objects.h"
+#include "event_db_repository.h"
+#include "sp_head.h"
+#include "sql_show.h"                // append_definer, append_identifier
+#include "mysql/psi/mysql_sp.h"
+#include "wsrep_mysqld.h"
+#ifdef WITH_WSREP
+#include "wsrep_trans_observer.h"
+#endif /* WITH_WSREP */
+/**
+  @addtogroup Event_Scheduler
+  @{
+*/
+
+#ifdef HAVE_PSI_INTERFACE
+void init_scheduler_psi_keys()
+{
+  const char *category= "scheduler";
+
+  PSI_server->register_statement(category, & Event_queue_element_for_exec::psi_info, 1);
+}
+
+PSI_statement_info Event_queue_element_for_exec::psi_info=
+{ 0, "event", 0};
+#endif
+
+/*************************************************************************/
+
+/**
+  Event_creation_ctx -- creation context of events.
+*/
+
+class Event_creation_ctx :public Stored_program_creation_ctx,
+                          public Sql_alloc
+{
+public:
+  static bool load_from_db(THD *thd,
+                           MEM_ROOT *event_mem_root,
+                           const char *db_name,
+                           const char *event_name,
+                           TABLE *event_tbl,
+                           Stored_program_creation_ctx **ctx);
+
+public:
+  virtual Stored_program_creation_ctx *clone(MEM_ROOT *mem_root)
+  {
+    return new (mem_root)
+               Event_creation_ctx(m_client_cs, m_connection_cl, m_db_cl);
+  }
+
+protected:
+  virtual Object_creation_ctx *create_backup_ctx(THD *thd) const
+  {
+    /*
+      We can avoid usual backup/restore employed in stored programs since we
+      know that this is a top level statement and the worker thread is
+      allocated exclusively to execute this event.
+    */
+
+    return NULL;
+  }
+
+private:
+  Event_creation_ctx(CHARSET_INFO *client_cs,
+                     CHARSET_INFO *connection_cl,
+                     CHARSET_INFO *db_cl)
+    : Stored_program_creation_ctx(client_cs, connection_cl, db_cl)
+  { }
+};
+
+/**************************************************************************
+  Event_creation_ctx implementation.
+**************************************************************************/
+
+bool
+Event_creation_ctx::load_from_db(THD *thd,
+                                 MEM_ROOT *event_mem_root,
+                                 const char *db_name,
+                                 const char *event_name,
+                                 TABLE *event_tbl,
+                                 Stored_program_creation_ctx **ctx)
+{
+  /* Load character set/collation attributes. */
+
+  CHARSET_INFO *client_cs;
+  CHARSET_INFO *connection_cl;
+  CHARSET_INFO *db_cl;
+
+  bool invalid_creation_ctx= FALSE;
+
+  if (load_charset(thd, event_mem_root,
+                   event_tbl->field[ET_FIELD_CHARACTER_SET_CLIENT],
+                   thd->variables.character_set_client,
+                   &client_cs))
+  {
+    sql_print_warning("Event '%s'.'%s': invalid value "
+                      "in column mysql.event.character_set_client.",
+                      (const char *) db_name,
+                      (const char *) event_name);
+
+    invalid_creation_ctx= TRUE;
+  }
+
+  if (load_collation(thd, event_mem_root,
+                     event_tbl->field[ET_FIELD_COLLATION_CONNECTION],
+                     thd->variables.collation_connection,
+                     &connection_cl))
+  {
+    sql_print_warning("Event '%s'.'%s': invalid value "
+                      "in column mysql.event.collation_connection.",
+                      (const char *) db_name,
+                      (const char *) event_name);
+
+    invalid_creation_ctx= TRUE;
+  }
+
+  if (load_collation(thd, event_mem_root,
+                     event_tbl->field[ET_FIELD_DB_COLLATION],
+                     NULL,
+                     &db_cl))
+  {
+    sql_print_warning("Event '%s'.'%s': invalid value "
+                      "in column mysql.event.db_collation.",
+                      (const char *) db_name,
+                      (const char *) event_name);
+
+    invalid_creation_ctx= TRUE;
+  }
+
+  /*
+    If we failed to resolve the database collation, load the default one
+    from the disk.
+  */
+
+  if (!db_cl)
+    db_cl= get_default_db_collation(thd, db_name);
+
+  /* Create the context. */
+
+  *ctx= new Event_creation_ctx(client_cs, connection_cl, db_cl);
+
+  return invalid_creation_ctx;
+}
+
+/*************************************************************************/
+
+/*
+  Initializes dbname and name of an Event_queue_element_for_exec
+  object
+
+  SYNOPSIS
+    Event_queue_element_for_exec::init()
+
+  RETURN VALUE
+    FALSE  OK
+    TRUE   Error (OOM)
+*/
+
+bool
+Event_queue_element_for_exec::init(const LEX_CSTRING &db, const LEX_CSTRING &n)
+{
+  if (!(dbname.str= my_strndup(key_memory_Event_queue_element_for_exec_names,
+                               db.str, dbname.length= db.length, MYF(MY_WME))))
+    return TRUE;
+  if (!(name.str= my_strndup(key_memory_Event_queue_element_for_exec_names,
+                             n.str, name.length= n.length, MYF(MY_WME))))
+  {
+    my_free(const_cast<char*>(dbname.str));
+    dbname.str= NULL;
+    return TRUE;
+  }
+  return FALSE;
+}
+
+
+/*
+  Destructor
+
+  SYNOPSIS
+    Event_queue_element_for_exec::~Event_queue_element_for_exec()
+*/
+
+Event_queue_element_for_exec::~Event_queue_element_for_exec()
+{
+  my_free(const_cast<char*>(dbname.str));
+  my_free(const_cast<char*>(name.str));
+}
+
+
+/*
+  Constructor
+
+  SYNOPSIS
+    Event_basic::Event_basic()
+*/
+
+Event_basic::Event_basic()
+{
+  DBUG_ENTER("Event_basic::Event_basic");
+  /* init memory root */
+  init_sql_alloc(key_memory_event_basic_root, &mem_root, 256, 512, MYF(0));
+  dbname.str= name.str= NULL;
+  dbname.length= name.length= 0;
+  time_zone= NULL;
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Destructor
+
+  SYNOPSIS
+    Event_basic::Event_basic()
+*/
+
+Event_basic::~Event_basic()
+{
+  DBUG_ENTER("Event_basic::~Event_basic");
+  free_root(&mem_root, MYF(0));
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Short function to load a char column into a LEX_CSTRING
+
+  SYNOPSIS
+    Event_basic::load_string_field()
+      field_name  The field( enum_events_table_field is not actually used
+                  because it's unknown in event_data_objects.h)
+      fields      The Field array
+      field_value The value
+*/
+
+bool
+Event_basic::load_string_fields(Field **fields, ...)
+{
+  bool ret= FALSE;
+  va_list args;
+  enum enum_events_table_field field_name;
+  LEX_CSTRING *field_value;
+
+  DBUG_ENTER("Event_basic::load_string_fields");
+
+  va_start(args, fields);
+  field_name= (enum enum_events_table_field) va_arg(args, int);
+  while (field_name < ET_FIELD_COUNT)
+  {
+    field_value= va_arg(args, LEX_CSTRING *);
+    if ((field_value->str= get_field(&mem_root, fields[field_name])) == NullS)
+    {
+      ret= TRUE;
+      break;
+    }
+    field_value->length= strlen(field_value->str);
+
+    field_name= (enum enum_events_table_field) va_arg(args, int);
+  }
+  va_end(args);
+
+  DBUG_RETURN(ret);
+}
+
+
+bool
+Event_basic::load_time_zone(THD *thd, const LEX_CSTRING *tz_name)
+{
+  String str(tz_name->str, strlen(tz_name->str), &my_charset_latin1);
+  time_zone= my_tz_find(thd, &str);
+
+  return (time_zone == NULL);
+}
+
+
+/*
+  Constructor
+
+  SYNOPSIS
+    Event_queue_element::Event_queue_element()
+*/
+
+Event_queue_element::Event_queue_element():
+  on_completion(Event_parse_data::ON_COMPLETION_DROP),
+  status(Event_parse_data::ENABLED), expression(0), dropped(FALSE),
+  execution_count(0)
+{
+  DBUG_ENTER("Event_queue_element::Event_queue_element");
+
+  starts= ends= execute_at= last_executed= 0;
+  starts_null= ends_null= execute_at_null= TRUE;
+
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Destructor
+
+  SYNOPSIS
+    Event_queue_element::Event_queue_element()
+*/
+Event_queue_element::~Event_queue_element() = default;
+
+
+/*
+  Constructor
+
+  SYNOPSIS
+    Event_timed::Event_timed()
+*/
+
+Event_timed::Event_timed():
+  created(0), modified(0), sql_mode(0)
+{
+  DBUG_ENTER("Event_timed::Event_timed");
+  init();
+  DBUG_VOID_RETURN;
+}
+
+
+/*
+  Destructor
+
+  SYNOPSIS
+    Event_timed::~Event_timed()
+*/
+
+Event_timed::~Event_timed() = default;
+
+
+/*
+  Constructor
+
+  SYNOPSIS
+    Event_job_data::Event_job_data()
+*/
+
+Event_job_data::Event_job_data()
+  :sql_mode(0)
+{
+}
+
+/*
+  Init all member variables
+
+  SYNOPSIS
+    Event_timed::init()
+*/
+
+void
+Event_timed::init()
+{
+  DBUG_ENTER("Event_timed::init");
+
+  definer_user.str= definer_host.str= body.str= comment.str= NULL;
+  definer_user.length= definer_host.length= body.length= comment.length= 0;
+
+  sql_mode= 0;
+
+  DBUG_VOID_RETURN;
+}
+
+
+/**
+  Load an event's body from a row from mysql.event.
+
+  @details This method is silent on errors and should behave like that.
+  Callers should handle throwing of error messages. The reason is that the
+  class should not know about how to deal with communication.
+
+  @return Operation status
+    @retval FALSE OK
+    @retval TRUE  Error
+*/
+
+bool
+Event_job_data::load_from_row(THD *thd, TABLE *table)
+{
+  const char *ptr;
+  size_t len;
+  LEX_CSTRING tz_name;
+
+  DBUG_ENTER("Event_job_data::load_from_row");
+
+  if (!table)
+    DBUG_RETURN(TRUE);
+
+  if (table->s->fields < ET_FIELD_COUNT)
+    DBUG_RETURN(TRUE);
+
+  if (load_string_fields(table->field,
+                         ET_FIELD_DB, &dbname,
+                         ET_FIELD_NAME, &name,
+                         ET_FIELD_BODY, &body,
+                         ET_FIELD_DEFINER, &definer,
+                         ET_FIELD_TIME_ZONE, &tz_name,
+                         ET_FIELD_COUNT))
+    DBUG_RETURN(TRUE);
+
+  if (load_time_zone(thd, &tz_name))
+    DBUG_RETURN(TRUE);
+
+  Event_creation_ctx::load_from_db(thd, &mem_root, dbname.str, name.str, table,
+                                   &creation_ctx);
+
+  ptr= strchr(definer.str, '@');
+
+  if (! ptr)
+    ptr= definer.str;
+
+  len= ptr - definer.str;
+  definer_user.str= strmake_root(&mem_root, definer.str, len);
+  definer_user.length= len;
+  len= definer.length - len - 1;
+  /* 1:because of @ */
+  definer_host.str= strmake_root(&mem_root, ptr + 1, len);
+  definer_host.length= len;
+
+  sql_mode= (sql_mode_t) table->field[ET_FIELD_SQL_MODE]->val_int();
+
+  DBUG_RETURN(FALSE);
+}
+
+
+/**
+  Load an event's body from a row from mysql.event.
+
+  @details This method is silent on errors and should behave like that.
+  Callers should handle throwing of error messages. The reason is that the
+  class should not know about how to deal with communication.
+
+  @return Operation status
+    @retval FALSE OK
+    @retval TRUE  Error
+*/
+
+bool
+Event_queue_element::load_from_row(THD *thd, TABLE *table)
+{
+  const char *ptr;
+  MYSQL_TIME time;
+  LEX_CSTRING tz_name;
+
+  DBUG_ENTER("Event_queue_element::load_from_row");
+
+  if (!table)
+    DBUG_RETURN(TRUE);
+
+  if (table->s->fields < ET_FIELD_COUNT)
+    DBUG_RETURN(TRUE);
+
+  if (load_string_fields(table->field,
+                         ET_FIELD_DB, &dbname,
+                         ET_FIELD_NAME, &name,
+                         ET_FIELD_DEFINER, &definer,
+                         ET_FIELD_TIME_ZONE, &tz_name,
+                         ET_FIELD_COUNT))
+    DBUG_RETURN(TRUE);
+
+  if (load_time_zone(thd, &tz_name))
+    DBUG_RETURN(TRUE);
+
+  starts_null= table->field[ET_FIELD_STARTS]->is_null();
+  uint not_used;
+  if (!starts_null)
+  {
+    /*
+      The expected data type for these columns in mysql.events:
+        starts, ends, execute_at, last_executed
+      is DATETIME. No nanosecond truncation should normally be needed,
+      unless the DBA changes them, e.g. to VARCHAR, DECIMAL, etc.
+      For this unexpected case let's use the default round mode,
+      according to the current session settings.
+    */
+    table->field[ET_FIELD_STARTS]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                   thd->temporal_round_mode());
+    starts= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
+  }
+
+  ends_null= table->field[ET_FIELD_ENDS]->is_null();
+  if (!ends_null)
+  {
+    table->field[ET_FIELD_ENDS]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                 thd->temporal_round_mode());
+    ends= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
+  }
+
+  if (!table->field[ET_FIELD_INTERVAL_EXPR]->is_null())
+    expression= table->field[ET_FIELD_INTERVAL_EXPR]->val_int();
+  else
+    expression= 0;
+  /*
+    If neigher STARTS and ENDS is set, then both fields are empty.
+    Hence, if ET_FIELD_EXECUTE_AT is empty there is an error.
+  */
+  execute_at_null= table->field[ET_FIELD_EXECUTE_AT]->is_null();
+  DBUG_ASSERT(!(starts_null && ends_null && !expression && execute_at_null));
+  if (!expression && !execute_at_null)
+  {
+    if (table->field[ET_FIELD_EXECUTE_AT]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                    thd->temporal_round_mode()))
+      DBUG_RETURN(TRUE);
+    execute_at= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
+  }
+
+  /*
+    We load the interval type from disk as string and then map it to
+    an integer. This decouples the values of enum interval_type
+    and values actually stored on disk. Therefore the type can be
+    reordered without risking incompatibilities of data between versions.
+  */
+  if (!table->field[ET_FIELD_TRANSIENT_INTERVAL]->is_null())
+  {
+    int i;
+    char buff[MAX_FIELD_WIDTH];
+    String str(buff, sizeof(buff), &my_charset_bin);
+    LEX_CSTRING tmp;
+
+    table->field[ET_FIELD_TRANSIENT_INTERVAL]->val_str(&str);
+    if (!(tmp.length= str.length()))
+      DBUG_RETURN(TRUE);
+
+    tmp.str= str.c_ptr_safe();
+
+    i= find_string_in_array(interval_type_to_name, &tmp, system_charset_info);
+    if (i < 0)
+      DBUG_RETURN(TRUE);
+    interval= (interval_type) i;
+  }
+
+  if (!table->field[ET_FIELD_LAST_EXECUTED]->is_null())
+  {
+    table->field[ET_FIELD_LAST_EXECUTED]->get_date(&time, TIME_NO_ZERO_DATE |
+                                                   thd->temporal_round_mode());
+    last_executed= my_tz_OFFSET0->TIME_to_gmt_sec(&time,&not_used);
+  }
+
+  if ((ptr= get_field(&mem_root, table->field[ET_FIELD_STATUS])) == NullS)
+    DBUG_RETURN(TRUE);
+
+  DBUG_PRINT("load_from_row", ("Event [%s] is [%s]", name.str, ptr));
+
+  /* Set event status (ENABLED | SLAVESIDE_DISABLED | DISABLED) */
+  switch (ptr[0])
+  {
+  case 'E' :
+    status = Event_parse_data::ENABLED;
+    break;
+  case 'S' :
+    status = Event_parse_data::SLAVESIDE_DISABLED;
+    break;
+  case 'D' :
+  default:
+    status = Event_parse_data::DISABLED;
+    break;
+  }
+  if ((ptr= get_field(&mem_root, table->field[ET_FIELD_ORIGINATOR])) == NullS)
+    DBUG_RETURN(TRUE);
+  originator = (uint32) table->field[ET_FIELD_ORIGINATOR]->val_int(); 
+
+  /* ToDo : Andrey . Find a way not to allocate ptr on event_mem_root */
+  if ((ptr= get_field(&mem_root,
+                      table->field[ET_FIELD_ON_COMPLETION])) == NullS)
+    DBUG_RETURN(TRUE);
+
+  on_completion= (ptr[0]=='D'? Event_parse_data::ON_COMPLETION_DROP:
+                               Event_parse_data::ON_COMPLETION_PRESERVE);
+
+  DBUG_RETURN(FALSE);
+}
+
+
+/**
+  Load an event's body from a row from mysql.event.
+
+  @details This method is silent on errors and should behave like that.
+  Callers should handle throwing of error messages. The reason is that the
+  class should not know about how to deal with communication.
+
+  @return Operation status
+    @retval FALSE OK
+    @retval TRUE  Error
+*/
+
+bool
+Event_timed::load_from_row(THD *thd, TABLE *table)
+{
+  const char *ptr;
+  size_t len;
+
+  DBUG_ENTER("Event_timed::load_from_row");
+
+  if (Event_queue_element::load_from_row(thd, table))
+    DBUG_RETURN(TRUE);
+
+  if (load_string_fields(table->field,
+                         ET_FIELD_BODY, &body,
+                         ET_FIELD_BODY_UTF8, &body_utf8,
+                         ET_FIELD_COUNT))
+    DBUG_RETURN(TRUE);
+
+  if (Event_creation_ctx::load_from_db(thd, &mem_root, dbname.str, name.str,
+                                       table, &creation_ctx))
+  {
+    push_warning_printf(thd,
+                        Sql_condition::WARN_LEVEL_WARN,
+                        ER_EVENT_INVALID_CREATION_CTX,
+                        ER_THD(thd, ER_EVENT_INVALID_CREATION_CTX),
+                        (const char *) dbname.str,
+                        (const char *) name.str);
+  }
+
+  ptr= strchr(definer.str, '@');
+
+  if (! ptr)
+    ptr= definer.str;
+
+  len= ptr - definer.str;
+  definer_user.str= strmake_root(&mem_root, definer.str, len);
+  definer_user.length= len;
+  len= definer.length - len - 1;
+  /* 1:because of @ */
+  definer_host.str= strmake_root(&mem_root, ptr + 1,  len);
+  definer_host.length= len;
+
+  created= table->field[ET_FIELD_CREATED]->val_int();
+  modified= table->field[ET_FIELD_MODIFIED]->val_int();
+
+  comment.str= get_field(&mem_root, table->field[ET_FIELD_COMMENT]);
+  if (comment.str != NullS)
+    comment.length= strlen(comment.str);
+  else
+    comment.length= 0;
+
+  sql_mode= (sql_mode_t) table->field[ET_FIELD_SQL_MODE]->val_int();
+
+  DBUG_RETURN(FALSE);
+}
+
+
+/*
+  add_interval() adds a specified interval to time 'ltime' in time
+  zone 'time_zone', and returns the result converted to the number of
+  seconds since epoch (aka Unix time; in UTC time zone).  Zero result
+  means an error.
+*/
+static
+my_time_t
+add_interval(MYSQL_TIME *ltime, const Time_zone *time_zone,
+             interval_type scale, INTERVAL interval)
+{
+  if (date_add_interval(current_thd, ltime, scale, interval))
+    return 0;
+
+  uint not_used;
+  return time_zone->TIME_to_gmt_sec(ltime, &not_used);
+}
+
+
+/*
+  Computes the sum of a timestamp plus interval.
+
+  SYNOPSIS
+    get_next_time()
+      time_zone     event time zone
+      next          the sum
+      start         add interval_value to this time
+      time_now      current time
+      i_value       quantity of time type interval to add
+      i_type        type of interval to add (SECOND, MINUTE, HOUR, WEEK ...)
+
+  RETURN VALUE
+    0  OK
+    1  Error
+
+  NOTES
+    1) If the interval is conversible to SECOND, like MINUTE, HOUR, DAY, WEEK.
+       Then we use TIMEDIFF()'s implementation as underlying and number of
+       seconds as resolution for computation.
+    2) In all other cases - MONTH, QUARTER, YEAR we use MONTH as resolution
+       and PERIOD_DIFF()'s implementation
+*/
+
+static
+bool get_next_time(const Time_zone *time_zone, my_time_t *next,
+                   my_time_t start, my_time_t time_now,
+                   int i_value, interval_type i_type)
+{
+  DBUG_ENTER("get_next_time");
+  DBUG_PRINT("enter", ("start: %lu  now: %lu", (long) start, (long) time_now));
+
+  DBUG_ASSERT(start <= time_now);
+
+  longlong months=0, seconds=0;
+
+  switch (i_type) {
+  case INTERVAL_YEAR:
+    months= i_value*12;
+    break;
+  case INTERVAL_QUARTER:
+    /* Has already been converted to months */
+  case INTERVAL_YEAR_MONTH:
+  case INTERVAL_MONTH:
+    months= i_value;
+    break;
+  case INTERVAL_WEEK:
+    /* WEEK has already been converted to days */
+  case INTERVAL_DAY:
+    seconds= i_value*24*3600;
+    break;
+  case INTERVAL_DAY_HOUR:
+  case INTERVAL_HOUR:
+    seconds= i_value*3600;
+    break;
+  case INTERVAL_DAY_MINUTE:
+  case INTERVAL_HOUR_MINUTE:
+  case INTERVAL_MINUTE:
+    seconds= i_value*60;
+    break;
+  case INTERVAL_DAY_SECOND:
+  case INTERVAL_HOUR_SECOND:
+  case INTERVAL_MINUTE_SECOND:
+  case INTERVAL_SECOND:
+    seconds= i_value;
+    break;
+  case INTERVAL_DAY_MICROSECOND:
+  case INTERVAL_HOUR_MICROSECOND:
+  case INTERVAL_MINUTE_MICROSECOND:
+  case INTERVAL_SECOND_MICROSECOND:
+  case INTERVAL_MICROSECOND:
+    /*
+     We should return an error here so SHOW EVENTS/ SELECT FROM I_S.EVENTS
+     would give an error then.
+    */
+    DBUG_RETURN(1);
+  case INTERVAL_LAST:
+    DBUG_ASSERT(0);
+  }
+  DBUG_PRINT("info", ("seconds: %ld  months: %ld", (long) seconds, (long) months));
+
+  MYSQL_TIME local_start;
+  MYSQL_TIME local_now;
+
+  /* Convert times from UTC to local. */
+  {
+    time_zone->gmt_sec_to_TIME(&local_start, start);
+    time_zone->gmt_sec_to_TIME(&local_now, time_now);
+  }
+
+  INTERVAL interval;
+  bzero(&interval, sizeof(interval));
+  my_time_t next_time= 0;
+
+  if (seconds)
+  {
+    ulonglong seconds_diff;
+    ulong microsec_diff;
+    bool negative= calc_time_diff(&local_now, &local_start, 1,
+                                  &seconds_diff, &microsec_diff);
+    if (!negative)
+    {
+      /*
+        The formula below returns the interval that, when added to
+        local_start, will always give the time in the future.
+      */
+      interval.second= seconds_diff - seconds_diff % seconds + seconds;
+      next_time= add_interval(&local_start, time_zone,
+                              INTERVAL_SECOND, interval);
+      if (next_time == 0)
+        goto done;
+    }
+
+    if (next_time <= time_now)
+    {
+      /*
+        If 'negative' is true above, then 'next_time == 0', and
+        'next_time <= time_now' is also true.  If negative is false,
+        then next_time was set, but perhaps to the value that is less
+        then time_now.  See below for elaboration.
+      */
+      DBUG_ASSERT(negative || next_time > 0);
+
+      /*
+        If local_now < local_start, i.e. STARTS time is in the future
+        according to the local time (it always in the past according
+        to UTC---this is a prerequisite of this function), then
+        STARTS is almost always in the past according to the local
+        time too.  However, in the time zone that has backward
+        Daylight Saving Time shift, the following may happen: suppose
+        we have a backward DST shift at certain date after 2:59:59,
+        i.e. local time goes 1:59:59, 2:00:00, ... , 2:59:59, (shift
+        here) 2:00:00 (again), ... , 2:59:59 (again), 3:00:00, ... .
+        Now suppose the time has passed the first 2:59:59, has been
+        shifted backward, and now is (the second) 2:20:00.  The user
+        does CREATE EVENT with STARTS 'current-date 2:40:00'.  Local
+        time 2:40:00 from create statement is treated by time
+        functions as the first such time, so according to UTC it comes
+        before the second 2:20:00.  But according to local time it is
+        obviously in the future, so we end up in this branch.
+
+        Since we are in the second pass through 2:00:00--2:59:59, and
+        any local time form this interval is treated by system
+        functions as the time from the first pass, we have to find the
+        time for the next execution that is past the DST-affected
+        interval (past the second 2:59:59 for our example,
+        i.e. starting from 3:00:00).  We do this in the loop until the
+        local time is mapped onto future UTC time.  'start' time is in
+        the past, so we may use 'do { } while' here, and add the first
+        interval right away.
+
+        Alternatively, it could be that local_now >= local_start.  Now
+        for the example above imagine we do CREATE EVENT with STARTS
+        'current-date 2:10:00'.  Local start 2:10 is in the past (now
+        is local 2:20), so we add an interval, and get next execution
+        time, say, 2:40.  It is in the future according to local time,
+        but, again, since we are in the second pass through
+        2:00:00--2:59:59, 2:40 will be converted into UTC time in the
+        past.  So we will end up in this branch again, and may add
+        intervals in a 'do { } while' loop.
+
+        Note that for any given event we may end up here only if event
+        next execution time will map to the time interval that is
+        passed twice, and only if the server was started during the
+        second pass, or the event is being created during the second
+        pass.  After that, we never will get here (unless we again
+        start the server during the second pass).  In other words,
+        such a condition is extremely rare.
+      */
+      interval.second= seconds;
+      do
+      {
+        next_time= add_interval(&local_start, time_zone,
+                                INTERVAL_SECOND, interval);
+        if (next_time == 0)
+          goto done;
+      }
+      while (next_time <= time_now);
+    }
+  }
+  else
+  {
+    long diff_months= ((long) local_now.year - (long) local_start.year)*12 +
+                      ((long) local_now.month - (long) local_start.month);
+
+    /*
+      Unlike for seconds above, the formula below returns the interval
+      that, when added to the local_start, will give the time in the
+      past, or somewhere in the current month.  We are interested in
+      the latter case, to see if this time has already passed, or is
+      yet to come this month.
+
+      Note that the time is guaranteed to be in the past unless
+      (diff_months % months == 0), but no good optimization is
+      possible here, because (diff_months % months == 0) is what will
+      happen most of the time, as get_next_time() will be called right
+      after the execution of the event.  We could pass last_executed
+      time to this function, and see if the execution has already
+      happened this month, but for that we will have to convert
+      last_executed from seconds since epoch to local broken-down
+      time, and this will greatly reduce the effect of the
+      optimization.  So instead we keep the code simple and clean.
+    */
+    interval.month= (ulong) (diff_months - diff_months % months);
+    next_time= add_interval(&local_start, time_zone,
+                            INTERVAL_MONTH, interval);
+    if (next_time == 0)
+      goto done;
+
+    if (next_time <= time_now)
+    {
+      interval.month= (ulong) months;
+      next_time= add_interval(&local_start, time_zone,
+                              INTERVAL_MONTH, interval);
+      if (next_time == 0)
+        goto done;
+    }
+  }
+
+  DBUG_ASSERT(time_now < next_time);
+
+  *next= next_time;
+
+done:
+  DBUG_PRINT("info", ("next_time: %ld", (long) next_time));
+  DBUG_RETURN(next_time == 0);
+}
+
+
+/*
+  Computes next execution time.
+
+  SYNOPSIS
+    Event_queue_element::compute_next_execution_time()
+
+  RETURN VALUE
+    FALSE  OK
+    TRUE   Error
+
+  NOTES
+    The time is set in execute_at, if no more executions the latter is
+    set to 0.
+*/
+
+bool
+Event_queue_element::compute_next_execution_time()
+{
+  my_time_t time_now;
+  DBUG_ENTER("Event_queue_element::compute_next_execution_time");
+  DBUG_PRINT("enter", ("starts: %lu  ends: %lu  last_executed: %lu  this: %p",
+                       (long) starts, (long) ends, (long) last_executed,
+                       this));
+
+  if (status != Event_parse_data::ENABLED)
+  {
+    DBUG_PRINT("compute_next_execution_time",
+               ("Event %s is DISABLED", name.str));
+    goto ret;
+  }
+  /* If one-time, no need to do computation */
+  if (!expression)
+  {
+    /* Let's check whether it was executed */
+    if (last_executed)
+    {
+      DBUG_PRINT("info",("One-time event %s.%s of was already executed",
+                         dbname.str, name.str));
+      dropped= (on_completion == Event_parse_data::ON_COMPLETION_DROP);
+      DBUG_PRINT("info",("One-time event will be dropped: %d.", dropped));
+
+      status= Event_parse_data::DISABLED;
+    }
+    goto ret;
+  }
+
+  time_now= current_thd->query_start();
+
+  DBUG_PRINT("info",("NOW: [%lu]", (ulong) time_now));
+
+  /* if time_now is after ends don't execute anymore */
+  if (!ends_null && ends < time_now)
+  {
+    DBUG_PRINT("info", ("NOW after ENDS, don't execute anymore"));
+    /* time_now is after ends. don't execute anymore */
+    execute_at= 0;
+    execute_at_null= TRUE;
+    if (on_completion == Event_parse_data::ON_COMPLETION_DROP)
+      dropped= TRUE;
+    DBUG_PRINT("info", ("Dropped: %d", dropped));
+    status= Event_parse_data::DISABLED;
+
+    goto ret;
+  }
+
+  /*
+    Here time_now is before or equals ends if the latter is set.
+    Let's check whether time_now is before starts.
+    If so schedule for starts.
+  */
+  if (!starts_null && time_now <= starts)
+  {
+    if (time_now == starts && starts == last_executed)
+    {
+      /*
+        do nothing or we will schedule for second time execution at starts.
+      */
+    }
+    else
+    {
+      DBUG_PRINT("info", ("STARTS is future, NOW <= STARTS,sched for STARTS"));
+      /*
+        starts is in the future
+        time_now before starts. Scheduling for starts
+      */
+      execute_at= starts;
+      execute_at_null= FALSE;
+      goto ret;
+    }
+  }
+
+  if (!starts_null && !ends_null)
+  {
+    /*
+      Both starts and m_ends are set and time_now is between them (incl.)
+      If last_executed is set then increase with m_expression. The new MYSQL_TIME is
+      after m_ends set execute_at to 0. And check for on_completion
+      If not set then schedule for now.
+    */
+    DBUG_PRINT("info", ("Both STARTS & ENDS are set"));
+    if (!last_executed)
+    {
+      DBUG_PRINT("info", ("Not executed so far."));
+    }
+
+    {
+      my_time_t next_exec;
+
+      if (get_next_time(time_zone, &next_exec, starts, time_now,
+                        (int) expression, interval))
+        goto err;
+
+      /* There was previous execution */
+      if (ends < next_exec)
+      {
+        DBUG_PRINT("info", ("Next execution of %s after ENDS. Stop executing.",
+                   name.str));
+        /* Next execution after ends. No more executions */
+        execute_at= 0;
+        execute_at_null= TRUE;
+        if (on_completion == Event_parse_data::ON_COMPLETION_DROP)
+          dropped= TRUE;
+        status= Event_parse_data::DISABLED;
+      }
+      else
+      {
+        DBUG_PRINT("info",("Next[%lu]", (ulong) next_exec));
+        execute_at= next_exec;
+        execute_at_null= FALSE;
+      }
+    }
+    goto ret;
+  }
+  else if (starts_null && ends_null)
+  {
+    /* starts is always set, so this is a dead branch !! */
+    DBUG_PRINT("info", ("Neither STARTS nor ENDS are set"));
+    /*
+      Both starts and m_ends are not set, so we schedule for the next
+      based on last_executed.
+    */
+    if (last_executed)
+    {
+      my_time_t next_exec;
+      if (get_next_time(time_zone, &next_exec, starts, time_now,
+                        (int) expression, interval))
+        goto err;
+      execute_at= next_exec;
+      DBUG_PRINT("info",("Next[%lu]", (ulong) next_exec));
+    }
+    else
+    {
+      /* last_executed not set. Schedule the event for now */
+      DBUG_PRINT("info", ("Execute NOW"));
+      execute_at= time_now;
+    }
+    execute_at_null= FALSE;
+  }
+  else
+  {
+    /* either starts or m_ends is set */
+    if (!starts_null)
+    {
+      DBUG_PRINT("info", ("STARTS is set"));
+      /*
+        - starts is set.
+        - starts is not in the future according to check made before
+        Hence schedule for starts + m_expression in case last_executed
+        is not set, otherwise to last_executed + m_expression
+      */
+      if (!last_executed)
+      {
+        DBUG_PRINT("info", ("Not executed so far."));
+      }
+
+      {
+        my_time_t next_exec;
+        if (get_next_time(time_zone, &next_exec, starts, time_now,
+                          (int) expression, interval))
+          goto err;
+        execute_at= next_exec;
+        DBUG_PRINT("info",("Next[%lu]", (ulong) next_exec));
+      }
+      execute_at_null= FALSE;
+    }
+    else
+    {
+      /* this is a dead branch, because starts is always set !!! */
+      DBUG_PRINT("info", ("STARTS is not set. ENDS is set"));
+      /*
+        - m_ends is set
+        - m_ends is after time_now or is equal
+        Hence check for m_last_execute and increment with m_expression.
+        If last_executed is not set then schedule for now
+      */
+
+      if (!last_executed)
+        execute_at= time_now;
+      else
+      {
+        my_time_t next_exec;
+
+        if (get_next_time(time_zone, &next_exec, starts, time_now,
+                          (int) expression, interval))
+          goto err;
+
+        if (ends < next_exec)
+        {
+          DBUG_PRINT("info", ("Next execution after ENDS. Stop executing."));
+          execute_at= 0;
+          execute_at_null= TRUE;
+          status= Event_parse_data::DISABLED;
+          if (on_completion == Event_parse_data::ON_COMPLETION_DROP)
+            dropped= TRUE;
+        }
+        else
+        {
+          DBUG_PRINT("info", ("Next[%lu]", (ulong) next_exec));
+          execute_at= next_exec;
+          execute_at_null= FALSE;
+        }
+      }
+    }
+    goto ret;
+  }
+ret:
+  DBUG_PRINT("info", ("ret: 0 execute_at: %lu", (long) execute_at));
+  DBUG_RETURN(FALSE);
+err:
+  DBUG_PRINT("info", ("ret=1"));
+  DBUG_RETURN(TRUE);
+}
+
+
+/*
+  Set the internal last_executed MYSQL_TIME struct to now. NOW is the
+  time according to thd->query_start(), so the THD's clock.
+
+  SYNOPSIS
+    Event_queue_element::mark_last_executed()
+      thd   thread context
+*/
+
+void
+Event_queue_element::mark_last_executed(THD *thd)
+{
+  last_executed= thd->query_start();
+
+  execution_count++;
+}
+
+
+static
+void
+append_datetime(String *buf, Time_zone *time_zone, my_time_t secs,
+                const char *name, uint len)
+{
+  char dtime_buff[20*2+32];/* +32 to make my_snprintf_{8bit|ucs2} happy */
+  buf->append(STRING_WITH_LEN(" "));
+  buf->append(name, len);
+  buf->append(STRING_WITH_LEN(" '"));
+  /*
+    Pass the buffer and the second param tells fills the buffer and
+    returns the number of chars to copy.
+  */
+  MYSQL_TIME time;
+  time_zone->gmt_sec_to_TIME(&time, secs);
+  buf->append(dtime_buff, my_datetime_to_str(&time, dtime_buff, 0));
+  buf->append(STRING_WITH_LEN("'"));
+}
+
+
+/*
+  Get SHOW CREATE EVENT as string
+
+  SYNOPSIS
+    Event_timed::get_create_event(THD *thd, String *buf)
+      thd    Thread
+      buf    String*, should be already allocated. CREATE EVENT goes inside.
+
+  RETURN VALUE
+    0                       OK
+    EVEX_MICROSECOND_UNSUP  Error (for now if mysql.event has been
+                            tampered and MICROSECONDS interval or
+                            derivative has been put there.
+*/
+
+int
+Event_timed::get_create_event(THD *thd, String *buf)
+{
+  char tmp_buf[2 * STRING_BUFFER_USUAL_SIZE];
+  String expr_buf(tmp_buf, sizeof(tmp_buf), system_charset_info);
+  expr_buf.length(0);
+
+  DBUG_ENTER("get_create_event");
+  DBUG_PRINT("ret_info",("body_len=[%d]body=[%s]",
+                         (int) body.length, body.str));
+
+  if (expression && Events::reconstruct_interval_expression(&expr_buf, interval,
+                                                            expression))
+    DBUG_RETURN(EVEX_MICROSECOND_UNSUP);
+
+  buf->append(STRING_WITH_LEN("CREATE "));
+  append_definer(thd, buf, &definer_user, &definer_host);
+  buf->append(STRING_WITH_LEN("EVENT "));
+  append_identifier(thd, buf, &name);
+
+  if (expression)
+  {
+    buf->append(STRING_WITH_LEN(" ON SCHEDULE EVERY "));
+    buf->append(expr_buf);
+    buf->append(' ');
+    LEX_CSTRING *ival= &interval_type_to_name[interval];
+    buf->append(ival->str, ival->length);
+
+    if (!starts_null)
+      append_datetime(buf, time_zone, starts, STRING_WITH_LEN("STARTS"));
+
+    if (!ends_null)
+      append_datetime(buf, time_zone, ends, STRING_WITH_LEN("ENDS"));
+  }
+  else
+  {
+    append_datetime(buf, time_zone, execute_at,
+                    STRING_WITH_LEN("ON SCHEDULE AT"));
+  }
+
+  if (on_completion == Event_parse_data::ON_COMPLETION_DROP)
+    buf->append(STRING_WITH_LEN(" ON COMPLETION NOT PRESERVE "));
+  else
+    buf->append(STRING_WITH_LEN(" ON COMPLETION PRESERVE "));
+
+  if (status == Event_parse_data::ENABLED)
+    buf->append(STRING_WITH_LEN("ENABLE"));
+  else if (status == Event_parse_data::SLAVESIDE_DISABLED)
+    buf->append(STRING_WITH_LEN("DISABLE ON SLAVE"));
+  else
+    buf->append(STRING_WITH_LEN("DISABLE"));
+
+  if (comment.length)
+  {
+    buf->append(STRING_WITH_LEN(" COMMENT "));
+    append_unescaped(buf, comment.str, comment.length);
+  }
+  buf->append(STRING_WITH_LEN(" DO "));
+  buf->append(&body);
+
+  DBUG_RETURN(0);
+}
+
+
+/**
+  Get an artificial stored procedure to parse as an event definition.
+*/
+
+bool
+Event_job_data::construct_sp_sql(THD *thd, String *sp_sql)
+{
+  LEX_CSTRING buffer;
+  const uint STATIC_SQL_LENGTH= 44;
+
+  DBUG_ENTER("Event_job_data::construct_sp_sql");
+
+  /*
+    Allocate a large enough buffer on the thread execution memory
+    root to avoid multiple [re]allocations on system heap
+  */
+  buffer.length= STATIC_SQL_LENGTH + name.length + body.length;
+  if (! (buffer.str= (char*) thd->alloc(buffer.length)))
+    DBUG_RETURN(TRUE);
+
+  sp_sql->set(buffer.str, buffer.length, system_charset_info);
+  sp_sql->length(0);
+
+
+  sp_sql->append(STRING_WITH_LEN("CREATE "));
+  sp_sql->append(STRING_WITH_LEN("PROCEDURE "));
+  /*
+    Let's use the same name as the event name to perhaps produce a
+    better error message in case it is a part of some parse error.
+    We're using append_identifier here to successfully parse
+    events with reserved names.
+  */
+  append_identifier(thd, sp_sql, &name);
+
+  /*
+    The default SQL security of a stored procedure is DEFINER. We
+    have already activated the security context of the event, so
+    let's execute the procedure with the invoker rights to save on
+    resets of security contexts.
+  */
+  sp_sql->append(STRING_WITH_LEN("() SQL SECURITY INVOKER "));
+
+  if (thd->variables.sql_mode & MODE_ORACLE)
+    sp_sql->append(STRING_WITH_LEN(" AS BEGIN "));
+  sp_sql->append(&body);
+  if (thd->variables.sql_mode & MODE_ORACLE)
+    sp_sql->append(STRING_WITH_LEN("; END"));
+
+  DBUG_RETURN(thd->is_fatal_error);
+}
+
+
+/**
+  Get DROP EVENT statement to binlog the drop of ON COMPLETION NOT
+  PRESERVE event.
+*/
+
+bool
+Event_job_data::construct_drop_event_sql(THD *thd, String *sp_sql)
+{
+  LEX_CSTRING buffer;
+  const uint STATIC_SQL_LENGTH= 14;
+
+  DBUG_ENTER("Event_job_data::construct_drop_event_sql");
+
+  buffer.length= STATIC_SQL_LENGTH + name.length*2 + dbname.length*2;
+  if (! (buffer.str= (char*) thd->alloc(buffer.length)))
+    DBUG_RETURN(TRUE);
+
+  sp_sql->set(buffer.str, buffer.length, system_charset_info);
+  sp_sql->length(0);
+
+  sp_sql->append(STRING_WITH_LEN("DROP EVENT "));
+  append_identifier(thd, sp_sql, &dbname);
+  sp_sql->append('.');
+  append_identifier(thd, sp_sql, &name);
+
+  DBUG_RETURN(thd->is_fatal_error);
+}
+
+/**
+  Compiles and executes the event (the underlying sp_head object)
+
+  @retval TRUE  error (reported to the error log)
+  @retval FALSE success
+*/
+
+bool
+Event_job_data::execute(THD *thd, bool drop)
+{
+  String sp_sql;
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+  Security_context event_sctx, *save_sctx= NULL;
+#endif
+  List<Item> empty_item_list;
+  bool ret= TRUE;
+
+  DBUG_ENTER("Event_job_data::execute");
+
+  thd->reset_for_next_command();
+
+#ifdef WITH_WSREP
+  wsrep_open(thd);
+  wsrep_before_command(thd);
+#endif /* WITH_WSREP */
+  /*
+    MySQL parser currently assumes that current database is either
+    present in THD or all names in all statements are fully specified.
+    And yet not fully specified names inside stored programs must be 
+    be supported, even if the current database is not set:
+    CREATE PROCEDURE db1.p1() BEGIN CREATE TABLE t1; END//
+    -- in this example t1 should be always created in db1 and the statement
+    must parse even if there is no current database.
+
+    To support this feature and still address the parser limitation,
+    we need to set the current database here.
+    We don't have to call mysql_change_db, since the checks performed
+    in it are unnecessary for the purpose of parsing, and
+    mysql_change_db will be invoked anyway later, to activate the
+    procedure database before it's executed.
+  */
+  thd->set_db(&dbname);
+
+  lex_start(thd);
+
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+  if (event_sctx.change_security_context(thd,
+                                         &definer_user, &definer_host,
+                                         &dbname, &save_sctx))
+  {
+    sql_print_error("Event Scheduler: "
+                    "[%s].[%s.%s] execution failed, "
+                    "failed to authenticate the user.",
+                    definer.str, dbname.str, name.str);
+    goto end;
+  }
+#endif
+
+  if (check_access(thd, EVENT_ACL, dbname.str, NULL, NULL, 0, 0))
+  {
+    /*
+      This aspect of behavior is defined in the worklog,
+      and this is how triggers work too: if TRIGGER
+      privilege is revoked from trigger definer,
+      triggers are not executed.
+    */
+    sql_print_error("Event Scheduler: "
+                    "[%s].[%s.%s] execution failed, "
+                    "user no longer has EVENT privilege.",
+                    definer.str, dbname.str, name.str);
+    goto end;
+  }
+
+  /*
+    Set up global thread attributes to reflect the properties of
+    this Event. We can simply reset these instead of usual
+    backup/restore employed in stored programs since we know that
+    this is a top level statement and the worker thread is
+    allocated exclusively to execute this event.
+  */
+
+  thd->variables.sql_mode= sql_mode;
+  thd->variables.time_zone= time_zone;
+
+  if (construct_sp_sql(thd, &sp_sql))
+    goto end;
+
+  thd->set_query(sp_sql.c_ptr_safe(), sp_sql.length());
+
+  {
+    Parser_state parser_state;
+    sql_digest_state *parent_digest= thd->m_digest;
+    PSI_statement_locker *parent_locker= thd->m_statement_psi;
+    bool res;
+
+    if (parser_state.init(thd, thd->query(), thd->query_length()))
+      goto end;
+
+    thd->m_digest= NULL;
+    thd->m_statement_psi= NULL;
+    res= parse_sql(thd, & parser_state, creation_ctx);
+    thd->m_digest= parent_digest;
+    thd->m_statement_psi= parent_locker;
+
+    if (res)
+    {
+      sql_print_error("Event Scheduler: %serror during compilation of %s.%s",
+                      thd->is_fatal_error ? "fatal " : "", dbname.str, name.str);
+      goto end;
+    }
+  }
+
+  {
+    sp_head *sphead= thd->lex->sphead;
+
+    DBUG_ASSERT(sphead);
+
+    sphead->m_flags|= sp_head::LOG_SLOW_STATEMENTS;
+    sphead->m_flags|= sp_head::LOG_GENERAL_LOG;
+
+    /*
+      construct_sp_sql() + parse_sql() set suid to SP_IS_NOT_SUID,
+      because we have the security context already set to the event
+      definer here. See more comments in construct_sp_sql().
+    */
+    DBUG_ASSERT(sphead->suid() == SP_IS_NOT_SUID);
+    sphead->m_sql_mode= sql_mode;
+    sphead->set_creation_ctx(creation_ctx);
+    sphead->optimize();
+
+    sphead->m_sp_share= MYSQL_GET_SP_SHARE(SP_TYPE_EVENT,
+                                           dbname.str, static_cast<uint>(dbname.length),
+                                           name.str, static_cast<uint>(name.length));
+    ret= sphead->execute_procedure(thd, &empty_item_list);
+    /*
+      There is no pre-locking and therefore there should be no
+      tables open and locked left after execute_procedure.
+    */
+  }
+
+end:
+  if (drop && likely(!thd->is_fatal_error))
+  {
+    /*
+      We must do it here since here we're under the right authentication
+      ID of the event definer.
+    */
+    sql_print_information("Event Scheduler: Dropping %s.%s",
+                          (const char *) dbname.str, (const char *) name.str);
+    /*
+      Construct a query for the binary log, to ensure the event is dropped
+      on the slave
+    */
+    if (construct_drop_event_sql(thd, &sp_sql))
+      ret= 1;
+    else
+    {
+      thd->set_query(sp_sql.c_ptr_safe(), sp_sql.length());
+
+      /*
+        NOTE: even if we run in read-only mode, we should be able to lock
+        the mysql.event table for writing. In order to achieve this, we
+        should call mysql_lock_tables() under the super-user.
+
+        Same goes for transaction access mode.
+        Temporarily reset it to read-write.
+      */
+
+      privilege_t saved_master_access(thd->security_ctx->master_access);
+      thd->security_ctx->master_access |= PRIV_IGNORE_READ_ONLY;
+      bool save_tx_read_only= thd->tx_read_only;
+      thd->tx_read_only= false;
+
+      /*
+         This code is processing event execution and does not have client
+         connection. Here, event execution will now execute a prepared
+         DROP EVENT statement, but thd->lex->sql_command is set to
+         SQLCOM_CREATE_PROCEDURE
+         DROP EVENT will be logged in binlog, and we have to
+         replicate it to make all nodes have consistent event definitions
+         Wsrep DDL replication is triggered inside Events::drop_event(),
+         and here we need to prepare the THD so that DDL replication is
+         possible, essentially it requires setting sql_command to
+         SQLCOMM_DROP_EVENT, we will switch sql_command for the duration
+         of DDL replication only.
+      */
+      const enum_sql_command sql_command_save= thd->lex->sql_command;
+      const bool sql_command_set= WSREP(thd);
+
+      if (sql_command_set)
+        thd->lex->sql_command = SQLCOM_DROP_EVENT;
+
+      ret= Events::drop_event(thd, &dbname, &name, FALSE);
+
+      if (sql_command_set)
+      {
+#ifdef WITH_WSREP
+	wsrep_to_isolation_end(thd);
+#endif
+        thd->lex->sql_command = sql_command_save;
+      }
+
+      thd->tx_read_only= save_tx_read_only;
+      thd->security_ctx->master_access= saved_master_access;
+    }
+  }
+#ifndef NO_EMBEDDED_ACCESS_CHECKS
+  if (save_sctx)
+    event_sctx.restore_security_context(thd, save_sctx);
+#endif
+#ifdef WITH_WSREP
+  wsrep_after_command_ignore_result(thd);
+  wsrep_close(thd);
+#endif /* WITH_WSREP */
+  thd->lex->unit.cleanup();
+  thd->end_statement();
+  thd->cleanup_after_query();
+  /* Avoid races with SHOW PROCESSLIST */
+  thd->reset_query();
+
+  DBUG_PRINT("info", ("EXECUTED %s.%s  ret: %d", dbname.str, name.str, ret));
+
+  DBUG_RETURN(ret);
+}
+
+
+/*
+  Checks whether two events are in the same schema
+
+  SYNOPSIS
+    event_basic_db_equal()
+      db  Schema
+      et  Compare et->dbname to `db`
+
+  RETURN VALUE
+    TRUE   Equal
+    FALSE  Not equal
+*/
+
+bool
+event_basic_db_equal(const LEX_CSTRING *db, Event_basic *et)
+{
+  return !sortcmp_lex_string(&et->dbname, db, system_charset_info);
+}
+
+
+/*
+  Checks whether an event has equal `db` and `name`
+
+  SYNOPSIS
+    event_basic_identifier_equal()
+      db   Schema
+      name Name
+      et   The event object
+
+  RETURN VALUE
+    TRUE   Equal
+    FALSE  Not equal
+*/
+
+bool
+event_basic_identifier_equal(const LEX_CSTRING *db, const LEX_CSTRING *name,
+                             Event_basic *b)
+{
+  return !sortcmp_lex_string(name, &b->name, system_charset_info) &&
+         !sortcmp_lex_string(db, &b->dbname, system_charset_info);
+}
+
+/**
+  @} (End of group Event_Scheduler)
+*/