ddl_log.cc

/*
   Copyright (c) 2000, 2019, Oracle and/or its affiliates.
   Copyright (c) 2010, 2021, MariaDB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1335  USA
*/

#include "mariadb.h"
#include "mysqld.h"
#include "sql_class.h"                          // init_sql_alloc()
#include "log.h"                                // sql_print_error()
#include "ddl_log.h"
#include "ha_partition.h"                       // PAR_EXT
#include "sql_table.h"                          // build_table_filename
#include "sql_statistics.h"                     // rename_table_in_stats_tables
#include "sql_view.h"                           // mysql_rename_view()
#include "strfunc.h"                            // strconvert
#include "sql_show.h"                           // append_identifier()
#include "sql_db.h"                             // drop_database_objects()
#include <mysys_err.h>                          // EE_LINK


/*--------------------------------------------------------------------------

  MODULE: DDL log
  -----------------

  This module is used to ensure that we can recover from crashes that
  occur in the middle of a meta-data operation in MySQL. E.g. DROP
  TABLE t1, t2; We need to ensure that both t1 and t2 are dropped and
  not only t1 and also that each table drop is entirely done and not
  "half-baked".

  To support this we create log entries for each meta-data statement
  in the ddl log while we are executing. These entries are dropped
  when the operation is completed.

  At recovery those entries that were not completed will be executed.

  There is only one ddl log in the system and it is protected by a mutex
  and there is a global struct that contains information about its current
  state.

  DDL recovery after a crash works the following way:

  - ddl_log_initialize() initializes the global global_ddl_log variable
    and opens the binary log if it exists. If it doesn't exists a new one
    is created.
  - ddl_log_close_binlogged_events() loops over all log events and checks if
    their xid (stored in the EXECUTE_CODE event) is in the binary log.  If xid
    exists in the binary log the entry is marked as finished in the ddl log.
  - After a new binary log is created and is open for new entries,
    ddl_log_execute_recovery() is executed on remaining open events:
    - Loop over all events
     - For each entry with DDL_LOG_ENTRY_CODE execute the remaining phases
       in ddl_log_execute_entry_no_lock()

  The ddl_log.log file is created at startup and deleted when server goes down.
  After the final recovery phase is done, the file is truncated.

  History:
  First version written in 2006 by Mikael Ronstrom
  Second version in 2020 by Monty
--------------------------------------------------------------------------*/

#define DDL_LOG_MAGIC_LENGTH 4
/* How many times to try to execute a ddl log entry that causes crashes */
#define DDL_LOG_MAX_RETRY 3
#define DDL_LOG_RETRY_MASK 0xFF
#define DDL_LOG_RETRY_BITS 8

uchar ddl_log_file_magic[]=
{ (uchar) 254, (uchar) 254, (uchar) 11, (uchar) 2 };

/* Action names for ddl_log_action_code */

const char *ddl_log_action_name[DDL_LOG_LAST_ACTION]=
{
  "Unknown", "partitioning delete", "partitioning rename",
  "partitioning replace", "partitioning exchange",
  "rename table", "rename view",
  "initialize drop table", "drop table",
  "drop view", "drop trigger", "drop db", "create table", "create view",
  "delete tmp file", "create trigger", "alter table", "store query"
};

/* Number of phases per entry */
const uchar ddl_log_entry_phases[DDL_LOG_LAST_ACTION]=
{
  0, 1, 1, 2,
  (uchar) EXCH_PHASE_END, (uchar) DDL_RENAME_PHASE_END, 1, 1,
  (uchar) DDL_DROP_PHASE_END, 1, 1,
  (uchar) DDL_DROP_DB_PHASE_END, (uchar) DDL_CREATE_TABLE_PHASE_END,
  (uchar) DDL_CREATE_VIEW_PHASE_END, 0, (uchar) DDL_CREATE_TRIGGER_PHASE_END,
  DDL_ALTER_TABLE_PHASE_END, 1
};


struct st_global_ddl_log
{
  uchar *file_entry_buf;
  DDL_LOG_MEMORY_ENTRY *first_free;
  DDL_LOG_MEMORY_ENTRY *first_used;
  File file_id;
  uint num_entries;
  uint name_pos;
  uint io_size;
  bool initialized;
  bool open, backup_done, created;
};

/*
  The following structure is only used during startup recovery
  for writing queries to the binary log.
 */

class st_ddl_recovery {
public:
  String drop_table;
  String drop_view;
  String query;
  String db;
  size_t drop_table_init_length, drop_view_init_length;
  char   current_db[NAME_LEN];
  uint   execute_entry_pos;
  ulonglong xid;
};

static st_global_ddl_log global_ddl_log;
static st_ddl_recovery   recovery_state;

mysql_mutex_t LOCK_gdl;

/* Positions to different data in a ddl log block */
static constexpr unsigned DDL_LOG_ENTRY_TYPE_POS= 0;
/*
  Note that ACTION_TYPE and PHASE_POS must be after each other.
  See update_phase()
*/
static constexpr unsigned DDL_LOG_ACTION_TYPE_POS= 1;
static constexpr unsigned DDL_LOG_PHASE_POS= 2;
static constexpr unsigned DDL_LOG_NEXT_ENTRY_POS= 4;
/* Flags to remember something unique about the query, like if .frm was used */
static constexpr unsigned DDL_LOG_FLAG_POS= 8;
/* Used to store XID entry that was written to binary log */
static constexpr unsigned DDL_LOG_XID_POS= 10;
/* Used to store unique uuid from the .frm file */
static constexpr unsigned DDL_LOG_UUID_POS= 18;
/* ID_POS can be used to store something unique, like file size (4 bytes) */
static constexpr unsigned DDL_LOG_ID_POS= DDL_LOG_UUID_POS + MY_UUID_SIZE;
static constexpr unsigned DDL_LOG_END_POS= DDL_LOG_ID_POS + 8;

/*
  Position to where names are stored in the ddl log blocks. The current
  value is stored in the header and can thus be changed if we need more
  space for constants in the header than what is between DDL_LOG_ID_POS and
  DDL_LOG_TMP_NAME_POS.
*/
static constexpr unsigned DDL_LOG_TMP_NAME_POS= 56;

/* Definitions for the ddl log header, the first block in the file */
/* IO_SIZE is stored in the header and can thus be changed */
static constexpr unsigned DDL_LOG_IO_SIZE= IO_SIZE;

/* Header is stored in positions 0-3 */
static constexpr unsigned DDL_LOG_IO_SIZE_POS= 4;
static constexpr unsigned DDL_LOG_NAME_OFFSET_POS= 6;
/* Marks if we have done a backup of the ddl log */
static constexpr unsigned DDL_LOG_BACKUP_OFFSET_POS= 8;
/* Sum of the above variables */
static constexpr unsigned DDL_LOG_HEADER_SIZE= 4+2+2+1;

static void ddl_log_free_lists();

/**
  Sync the ddl log file.

  @return Operation status
    @retval FALSE  Success
    @retval TRUE   Error
*/

static bool ddl_log_sync_file()
{
  DBUG_ENTER("ddl_log_sync_file");
  DBUG_RETURN(mysql_file_sync(global_ddl_log.file_id, MYF(MY_WME)));
}

/* Same as above, but ensure we have the LOCK_gdl locked */

static bool ddl_log_sync_no_lock()
{
  DBUG_ENTER("ddl_log_sync_no_lock");

  mysql_mutex_assert_owner(&LOCK_gdl);
  DBUG_RETURN(ddl_log_sync_file());
}


/**
  Create ddl log file name.
  @param file_name                   Filename setup
*/

static inline void create_ddl_log_file_name(char *file_name, bool backup)
{
  fn_format(file_name, opt_ddl_recovery_file, mysql_data_home,
            backup ? "-backup.log" : ".log", MYF(MY_REPLACE_EXT));
}


/**
  Write ddl log header.

  @return Operation status
    @retval TRUE                      Error
    @retval FALSE                     Success
*/

static bool write_ddl_log_header()
{
  uchar header[DDL_LOG_HEADER_SIZE];
  DBUG_ENTER("write_ddl_log_header");

  memcpy(&header, ddl_log_file_magic, DDL_LOG_MAGIC_LENGTH);
  int2store(&header[DDL_LOG_IO_SIZE_POS],  global_ddl_log.io_size);
  int2store(&header[DDL_LOG_NAME_OFFSET_POS], global_ddl_log.name_pos);
  header[DDL_LOG_BACKUP_OFFSET_POS]= 0;

  if (mysql_file_pwrite(global_ddl_log.file_id,
                        header, sizeof(header), 0,
                        MYF(MY_WME | MY_NABP)))
    DBUG_RETURN(TRUE);
  DBUG_RETURN(ddl_log_sync_file());
}


/*
  Mark in the ddl log file that we have made a backup of it
*/

static void mark_ddl_log_header_backup_done()
{
  uchar marker[1];
  marker[0]= 1;
  (void) mysql_file_pwrite(global_ddl_log.file_id,
                           marker, sizeof(marker), DDL_LOG_BACKUP_OFFSET_POS,
                           MYF(MY_WME | MY_NABP));
}


void ddl_log_create_backup_file()
{
  char org_file_name[FN_REFLEN];
  char backup_file_name[FN_REFLEN];

  create_ddl_log_file_name(org_file_name, 0);
  create_ddl_log_file_name(backup_file_name, 1);

  my_copy(org_file_name, backup_file_name, MYF(MY_WME));
  mark_ddl_log_header_backup_done();
}


/**
  Read one entry from ddl log file.

  @param entry_pos                     Entry number to read

  @return Operation status
    @retval true   Error
    @retval false  Success
*/

static bool read_ddl_log_file_entry(uint entry_pos)
{
  uchar *file_entry_buf= global_ddl_log.file_entry_buf;
  size_t io_size= global_ddl_log.io_size;
  DBUG_ENTER("read_ddl_log_file_entry");

  mysql_mutex_assert_owner(&LOCK_gdl);
  DBUG_RETURN (mysql_file_pread(global_ddl_log.file_id,
                                file_entry_buf, io_size,
                                io_size * entry_pos,
                                MYF(MY_WME | MY_NABP)));
}


/**
  Write one entry to ddl log file.

  @param entry_pos  Entry number to write

  @return
    @retval true   Error
    @retval false  Success
*/

static bool write_ddl_log_file_entry(uint entry_pos)
{
  bool error= FALSE;
  File file_id= global_ddl_log.file_id;
  uchar *file_entry_buf= global_ddl_log.file_entry_buf;
  DBUG_ENTER("write_ddl_log_file_entry");

  mysql_mutex_assert_owner(&LOCK_gdl);          // To be removed
  DBUG_RETURN(mysql_file_pwrite(file_id, file_entry_buf,
                                global_ddl_log.io_size,
                                global_ddl_log.io_size * entry_pos,
                                MYF(MY_WME | MY_NABP)));
  DBUG_RETURN(error);
}


/**
  Update phase of ddl log entry

  @param entry_pos   ddl_log entry to update
  @param phase       New phase

  @return
  @retval 0           ok
  @retval 1           Write error. Error given

 This is done without locks as it's guaranteed to be atomic
*/

static bool update_phase(uint entry_pos, uchar phase)
{
  DBUG_ENTER("update_phase");
  DBUG_PRINT("ddl_log", ("pos: %u  phase: %u", entry_pos, (uint) phase));

  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, &phase, 1,
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_PHASE_POS,
                                MYF(MY_WME | MY_NABP)) ||
              ddl_log_sync_file());
}


/*
  Update flags in ddl log entry

  This is not synced as it usually followed by a phase change, which will sync.
*/

static bool update_flags(uint entry_pos, uint16 flags)
{
  uchar buff[2];
  DBUG_ENTER("update_flags");

  int2store(buff, flags);
  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, buff, sizeof(buff),
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_FLAG_POS,
                                MYF(MY_WME | MY_NABP)));
}


static bool update_next_entry_pos(uint entry_pos, uint next_entry)
{
  uchar buff[4];
  DBUG_ENTER("update_next_entry_pos");

  DBUG_PRINT("ddl_log", ("pos: %u->%u", entry_pos, next_entry));

  int4store(buff, next_entry);
  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, buff, sizeof(buff),
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_NEXT_ENTRY_POS,
                                MYF(MY_WME | MY_NABP)));
}


static bool update_xid(uint entry_pos, ulonglong xid)
{
  uchar buff[8];
  DBUG_ENTER("update_xid");

  int8store(buff, xid);
  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, buff, sizeof(buff),
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_XID_POS,
                                MYF(MY_WME | MY_NABP)) ||
              ddl_log_sync_file());
}


static bool update_unique_id(uint entry_pos, ulonglong id)
{
  uchar buff[8];
  DBUG_ENTER("update_unique_xid");

  int8store(buff, id);
  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, buff, sizeof(buff),
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_ID_POS,
                                MYF(MY_WME | MY_NABP)) ||
              ddl_log_sync_file());
}


/*
  Disable an execute entry

  @param entry_pos  ddl_log entry to update

  Notes:
  We don't need sync here as this is mainly done during
  recover phase to mark already done entries. We instead sync all entries
  at the same time.
*/

static bool disable_execute_entry(uint entry_pos)
{
  uchar buff[1];
  DBUG_ENTER("disable_execute_entry");
  DBUG_PRINT("ddl_log", ("pos: {%u}", entry_pos));

  buff[0]= DDL_LOG_IGNORE_ENTRY_CODE;
  DBUG_RETURN(mysql_file_pwrite(global_ddl_log.file_id, buff, sizeof(buff),
                                global_ddl_log.io_size * entry_pos +
                                DDL_LOG_ENTRY_TYPE_POS,
                                MYF(MY_WME | MY_NABP)));
}

/*
  Disable an execute entry
*/

bool ddl_log_disable_execute_entry(DDL_LOG_MEMORY_ENTRY **active_entry)
{
  bool res= disable_execute_entry((*active_entry)->entry_pos);
  ddl_log_sync_no_lock();
  return res;
}


/*
  Check if an executive entry is active

  @return 0  Entry is active
  @return 1  Entry is not active
*/

static bool is_execute_entry_active(uint entry_pos)
{
  uchar buff[1];
  DBUG_ENTER("disable_execute_entry");

  if (mysql_file_pread(global_ddl_log.file_id, buff, sizeof(buff),
                       global_ddl_log.io_size * entry_pos +
                       DDL_LOG_ENTRY_TYPE_POS,
                       MYF(MY_WME | MY_NABP)))
    DBUG_RETURN(1);
  DBUG_RETURN(buff[0] == (uchar) DDL_LOG_EXECUTE_CODE);
}


/**
  Read header of ddl log file.

  When we read the ddl log header we get information about maximum sizes
  of names in the ddl log and we also get information about the number
  of entries in the ddl log.

  This is read only once at server startup, so no mutex is needed.

  @return Last entry in ddl log (0 if no entries).
  @return -1 if log could not be opened or could not be read
*/

static int read_ddl_log_header(const char *file_name)
{
  uchar header[DDL_LOG_HEADER_SIZE];
  int max_entry;
  int file_id;
  uint io_size;
  DBUG_ENTER("read_ddl_log_header");

  if ((file_id= mysql_file_open(key_file_global_ddl_log,
                                file_name,
                                O_RDWR | O_BINARY, MYF(0))) < 0)
    DBUG_RETURN(-1);

  if (mysql_file_read(file_id,
                      header, sizeof(header), MYF(MY_WME | MY_NABP)))
  {
    /* Write message into error log */
    sql_print_error("DDL_LOG: Failed to read ddl log file '%s' during "
                    "recovery", file_name);
    goto err;
  }

  if (memcmp(header, ddl_log_file_magic, 4))
  {
    /* Probably upgrade from MySQL 10.5 or earlier */
    sql_print_warning("DDL_LOG: Wrong header in %s.  Assuming it is an old "
                      "recovery file from MariaDB 10.5 or earlier. "
                      "Skipping DDL recovery", file_name);
    goto err;
  }

  io_size=  uint2korr(&header[DDL_LOG_IO_SIZE_POS]);
  global_ddl_log.name_pos= uint2korr(&header[DDL_LOG_NAME_OFFSET_POS]);
  global_ddl_log.backup_done= header[DDL_LOG_BACKUP_OFFSET_POS];

  max_entry= (uint) (mysql_file_seek(file_id, 0L, MY_SEEK_END, MYF(0)) /
                     io_size);
  if (max_entry)
    max_entry--;                                // Don't count first block

  if (!(global_ddl_log.file_entry_buf= (uchar*)
        my_malloc(key_memory_DDL_LOG_MEMORY_ENTRY, io_size,
                  MYF(MY_WME | MY_ZEROFILL))))
    goto err;

  global_ddl_log.open= TRUE;
  global_ddl_log.created= 0;
  global_ddl_log.file_id= file_id;
  global_ddl_log.num_entries= max_entry;
  global_ddl_log.io_size= io_size;
  DBUG_RETURN(max_entry);

err:
  if (file_id >= 0)
    my_close(file_id, MYF(0));
  /* We return -1 to force the ddl log to be re-created */
  DBUG_RETURN(-1);
}


/*
  Store and read strings in ddl log buffers

  Format is:
    2 byte: length (not counting end \0)
    X byte: string value of length 'length'
    1 byte: \0
*/

static uchar *store_string(uchar *pos, uchar *end, const LEX_CSTRING *str)
{
  uint32 length= (uint32) str->length;
  if (unlikely(pos + 2 + length + 1 > end))
  {
    DBUG_ASSERT(0);
    return end;                                 // Overflow
  }

  int2store(pos, length);
  if (likely(length))
    memcpy(pos+2, str->str, length);
  pos[2+length]= 0;                             // Store end \0
  return pos + 2 + length +1;
}


static LEX_CSTRING get_string(uchar **pos, const uchar *end)
{
  LEX_CSTRING tmp;
  uint32 length;
  if (likely(*pos + 3 <= end))
  {
    length= uint2korr(*pos);
    if (likely(*pos + 2 + length + 1 <= end))
    {
      char *str= (char*) *pos+2;
      *pos= *pos + 2 + length + 1;
      tmp.str= str;
      tmp.length= length;
      return tmp;
    }
  }
  /*
    Overflow on read, should never happen
    Set *pos to end to ensure any future calls also returns empty string
  */
  DBUG_ASSERT(0);
  *pos= (uchar*) end;
  tmp.str= "";
  tmp.length= 0;
  return tmp;
}


/**
  Convert from ddl_log_entry struct to file_entry_buf binary blob.

  @param ddl_log_entry   filled in ddl_log_entry struct.
*/

static void set_global_from_ddl_log_entry(const DDL_LOG_ENTRY *ddl_log_entry)
{
  uchar *file_entry_buf= global_ddl_log.file_entry_buf, *pos, *end;

  mysql_mutex_assert_owner(&LOCK_gdl);

  file_entry_buf[DDL_LOG_ENTRY_TYPE_POS]=  (uchar) ddl_log_entry->entry_type;
  file_entry_buf[DDL_LOG_ACTION_TYPE_POS]= (uchar) ddl_log_entry->action_type;
  file_entry_buf[DDL_LOG_PHASE_POS]=       (uchar) ddl_log_entry->phase;
  int4store(file_entry_buf+DDL_LOG_NEXT_ENTRY_POS, ddl_log_entry->next_entry);
  int2store(file_entry_buf+DDL_LOG_FLAG_POS, ddl_log_entry->flags);
  int8store(file_entry_buf+DDL_LOG_XID_POS,  ddl_log_entry->xid);
  memcpy(file_entry_buf+DDL_LOG_UUID_POS,   ddl_log_entry->uuid, MY_UUID_SIZE);
  int8store(file_entry_buf+DDL_LOG_ID_POS,  ddl_log_entry->unique_id);
  bzero(file_entry_buf+DDL_LOG_END_POS,
        global_ddl_log.name_pos - DDL_LOG_END_POS);

  pos= file_entry_buf + global_ddl_log.name_pos;
  end= file_entry_buf + global_ddl_log.io_size;

  pos= store_string(pos, end, &ddl_log_entry->handler_name);
  pos= store_string(pos, end, &ddl_log_entry->db);
  pos= store_string(pos, end, &ddl_log_entry->name);
  pos= store_string(pos, end, &ddl_log_entry->from_handler_name);
  pos= store_string(pos, end, &ddl_log_entry->from_db);
  pos= store_string(pos, end, &ddl_log_entry->from_name);
  pos= store_string(pos, end, &ddl_log_entry->tmp_name);
  pos= store_string(pos, end, &ddl_log_entry->extra_name);
  bzero(pos, global_ddl_log.io_size - (pos - file_entry_buf));
}


/*
  Calculate how much space we have left in the log entry for one string

  This can be used to check if we have space to store the query string
  in the block.
*/

static size_t ddl_log_free_space_in_entry(const DDL_LOG_ENTRY *ddl_log_entry)
{
  size_t length= global_ddl_log.name_pos + 3*7;   // 3 byte per string below
  length+= ddl_log_entry->handler_name.length;
  length+= ddl_log_entry->db.length;
  length+= ddl_log_entry->name.length;
  length+= ddl_log_entry->from_handler_name.length;
  length+= ddl_log_entry->from_db.length;
  length+= ddl_log_entry->from_name.length;
  length+= ddl_log_entry->tmp_name.length;
  length+= ddl_log_entry->extra_name.length;
  return global_ddl_log.io_size - length - 3;   // 3 is for storing next string
}


/**
  Convert from file_entry_buf binary blob to ddl_log_entry struct.

  @param[out] ddl_log_entry   struct to fill in.

  @note Strings (names) are pointing to the global_ddl_log structure,
  so LOCK_gdl needs to be hold until they are read or copied.
*/

static void set_ddl_log_entry_from_global(DDL_LOG_ENTRY *ddl_log_entry,
                                          const uint read_entry)
{
  uchar *file_entry_buf= global_ddl_log.file_entry_buf, *pos;
  const uchar *end= file_entry_buf + global_ddl_log.io_size;
  uchar single_char;

  mysql_mutex_assert_owner(&LOCK_gdl);
  ddl_log_entry->entry_pos= read_entry;
  single_char= file_entry_buf[DDL_LOG_ENTRY_TYPE_POS];
  ddl_log_entry->entry_type= (enum ddl_log_entry_code) single_char;
  single_char= file_entry_buf[DDL_LOG_ACTION_TYPE_POS];
  ddl_log_entry->action_type= (enum ddl_log_action_code) single_char;
  ddl_log_entry->phase= file_entry_buf[DDL_LOG_PHASE_POS];
  ddl_log_entry->next_entry= uint4korr(&file_entry_buf[DDL_LOG_NEXT_ENTRY_POS]);
  ddl_log_entry->flags= uint2korr(file_entry_buf + DDL_LOG_FLAG_POS);
  ddl_log_entry->xid=   uint8korr(file_entry_buf + DDL_LOG_XID_POS);
  ddl_log_entry->unique_id=  uint8korr(file_entry_buf + DDL_LOG_ID_POS);
  memcpy(ddl_log_entry->uuid, file_entry_buf+ DDL_LOG_UUID_POS, MY_UUID_SIZE);

  pos= file_entry_buf + global_ddl_log.name_pos;
  ddl_log_entry->handler_name= get_string(&pos, end);
  ddl_log_entry->db=           get_string(&pos, end);
  ddl_log_entry->name=         get_string(&pos, end);
  ddl_log_entry->from_handler_name= get_string(&pos, end);
  ddl_log_entry->from_db=      get_string(&pos, end);
  ddl_log_entry->from_name=    get_string(&pos, end);
  ddl_log_entry->tmp_name=     get_string(&pos, end);
  ddl_log_entry->extra_name=   get_string(&pos, end);
}


/**
  Read a ddl log entry.

  Read a specified entry in the ddl log.

  @param read_entry               Number of entry to read
  @param[out] entry_info          Information from entry

  @return Operation status
    @retval TRUE                     Error
    @retval FALSE                    Success
*/

static bool read_ddl_log_entry(uint read_entry, DDL_LOG_ENTRY *ddl_log_entry)
{
  DBUG_ENTER("read_ddl_log_entry");

  if (read_ddl_log_file_entry(read_entry))
  {
    sql_print_error("DDL_LOG: Failed to read entry %u", read_entry);
    DBUG_RETURN(TRUE);
  }
  set_ddl_log_entry_from_global(ddl_log_entry, read_entry);
  DBUG_RETURN(FALSE);
}


/**
   Create the ddl log file

  @return Operation status
    @retval TRUE                     Error
    @retval FALSE                    Success
*/

static bool create_ddl_log()
{
  char file_name[FN_REFLEN];
  DBUG_ENTER("create_ddl_log");

  ddl_log_free_lists();
  global_ddl_log.open= 0;
  global_ddl_log.created= 1;
  global_ddl_log.num_entries= 0;
  global_ddl_log.name_pos= DDL_LOG_TMP_NAME_POS;
  global_ddl_log.num_entries= 0;
  global_ddl_log.backup_done= 0;

  /*
    Fix file_entry_buf if the old log had a different io_size or if open of old
    log didn't succeed.
  */
  if (global_ddl_log.io_size != DDL_LOG_IO_SIZE)
  {
    uchar *ptr= (uchar*)
      my_realloc(key_memory_DDL_LOG_MEMORY_ENTRY,
                 global_ddl_log.file_entry_buf, DDL_LOG_IO_SIZE,
                 MYF(MY_WME | MY_ALLOW_ZERO_PTR));
    if (ptr)                                    // Resize succeded */
    {
      global_ddl_log.file_entry_buf= ptr;
      global_ddl_log.io_size= DDL_LOG_IO_SIZE;
    }
    if (!global_ddl_log.file_entry_buf)
      DBUG_RETURN(TRUE);
  }
  DBUG_ASSERT(global_ddl_log.file_entry_buf);
  bzero(global_ddl_log.file_entry_buf, global_ddl_log.io_size);
  create_ddl_log_file_name(file_name, 0);
  if ((global_ddl_log.file_id=
       mysql_file_create(key_file_global_ddl_log,
                         file_name, CREATE_MODE,
                         O_RDWR | O_TRUNC | O_BINARY,
                         MYF(MY_WME | ME_ERROR_LOG))) < 0)
  {
    /* Couldn't create ddl log file, this is serious error */
    sql_print_error("DDL_LOG: Failed to create ddl log file: %s", file_name);
    my_free(global_ddl_log.file_entry_buf);
    global_ddl_log.file_entry_buf= 0;
    DBUG_RETURN(TRUE);
  }
  if (write_ddl_log_header())
  {
    (void) mysql_file_close(global_ddl_log.file_id, MYF(MY_WME));
    my_free(global_ddl_log.file_entry_buf);
    global_ddl_log.file_entry_buf= 0;
    DBUG_RETURN(TRUE);
  }
  global_ddl_log.open= TRUE;
  DBUG_RETURN(FALSE);
}


/**
  Open ddl log and initialise ddl log variables
  Create a backuip of of
*/

bool ddl_log_initialize()
{
  char file_name[FN_REFLEN];
  DBUG_ENTER("ddl_log_initialize");

  bzero(&global_ddl_log, sizeof(global_ddl_log));
  global_ddl_log.file_id= (File) -1;
  global_ddl_log.initialized= 1;

  mysql_mutex_init(key_LOCK_gdl, &LOCK_gdl, MY_MUTEX_INIT_SLOW);

  create_ddl_log_file_name(file_name, 0);
  if (unlikely(read_ddl_log_header(file_name) < 0))
  {
    /* Fatal error, log not opened. Recreate it */
    if (create_ddl_log())
      DBUG_RETURN(1);
  }
  DBUG_RETURN(0);
}


/**
  @brief Deactivate an individual entry.

  @details For complex rename operations we need to deactivate individual
  entries.

  During replace operations where we start with an existing table called
  t1 and a replacement table called t1#temp or something else and where
  we want to delete t1 and rename t1#temp to t1 this is not possible to
  do in a safe manner unless the ddl log is informed of the phases in
  the change.

  Delete actions are 1-phase actions that can be ignored immediately after
  being executed.
  Rename actions from x to y is also a 1-phase action since there is no
  interaction with any other handlers named x and y.
  Replace action where drop y and x -> y happens needs to be a two-phase
  action. Thus the first phase will drop y and the second phase will
  rename x -> y.

  @param entry_pos     Entry position of record to change

  @return Operation status
    @retval TRUE      Error
    @retval FALSE     Success
*/

static bool ddl_log_increment_phase_no_lock(uint entry_pos)
{
  uchar *file_entry_buf= global_ddl_log.file_entry_buf;
  DBUG_ENTER("ddl_log_increment_phase_no_lock");

  mysql_mutex_assert_owner(&LOCK_gdl);
  if (!read_ddl_log_file_entry(entry_pos))
  {
    ddl_log_entry_code  code=   ((ddl_log_entry_code)
                                 file_entry_buf[DDL_LOG_ENTRY_TYPE_POS]);
    ddl_log_action_code action= ((ddl_log_action_code)
                                 file_entry_buf[DDL_LOG_ACTION_TYPE_POS]);

    if (code == DDL_LOG_ENTRY_CODE && action < (uint) DDL_LOG_LAST_ACTION)
    {
      /*
        Log entry:
        Increase the phase by one. If complete mark it done (IGNORE).
      */
      char phase= file_entry_buf[DDL_LOG_PHASE_POS]+ 1;
      if (ddl_log_entry_phases[action] <= phase)
      {
        DBUG_ASSERT(phase == ddl_log_entry_phases[action]);
        /* Same effect as setting DDL_LOG_IGNORE_ENTRY_CODE */
        phase= DDL_LOG_FINAL_PHASE;
      }
      file_entry_buf[DDL_LOG_PHASE_POS]= phase;
      if (update_phase(entry_pos, phase))
        DBUG_RETURN(TRUE);
    }
    else
    {
      /*
        Trying to deactivate an execute entry or already inactive entry.
        This should not happen
      */
      DBUG_ASSERT(0);
    }
  }
  else
  {
    sql_print_error("DDL_LOG: Failed in reading entry before updating it");
    DBUG_RETURN(TRUE);
  }
  DBUG_RETURN(FALSE);
}


/*
  Increment phase and sync ddl log. This expects LOCK_gdl to be locked
*/

static bool increment_phase(uint entry_pos)
{
  if (ddl_log_increment_phase_no_lock(entry_pos))
    return 1;
  ddl_log_sync_no_lock();
  return 0;
}


/*
  Ignore errors from the file system about:
  - Non existing tables or file (from drop table or delete file)
  - Error about tables files that already exists.
  - Error from delete table (from Drop_table_error_handler)
  - Wrong trigger definer   (from Drop_table_error_handler)
*/

class ddl_log_error_handler : public Internal_error_handler
{
public:
  int handled_errors;
  int unhandled_errors;
  int first_error;
  bool only_ignore_non_existing_errors;

  ddl_log_error_handler() : handled_errors(0), unhandled_errors(0),
                            first_error(0), only_ignore_non_existing_errors(0)
  {}

  bool handle_condition(THD *,
                        uint sql_errno,
                        const char*,
                        Sql_condition::enum_warning_level *level,
                        const char*,
                        Sql_condition **cond_hdl) override
  {
    *cond_hdl= NULL;
    if (non_existing_table_error(sql_errno) ||
        (!only_ignore_non_existing_errors &&
         (sql_errno == EE_LINK ||
          sql_errno == EE_DELETE || sql_errno == ER_TRG_NO_DEFINER)))
    {
      handled_errors++;
      return TRUE;
    }
    if (!first_error)
      first_error= sql_errno;

    if (*level == Sql_condition::WARN_LEVEL_ERROR)
      unhandled_errors++;
    return FALSE;
  }
  bool safely_trapped_errors()
  {
    return (handled_errors > 0 && unhandled_errors == 0);
  }
};


/*
  Build a filename for a table, trigger file or .frm
  Delete also any temporary file suffixed with ~

  @return 0  Temporary file deleted
  @return 1  No temporary file found
*/

static bool build_filename_and_delete_tmp_file(char *path, size_t path_length,
                                               const LEX_CSTRING *db,
                                               const LEX_CSTRING *name,
                                               const char *ext,
                                               PSI_file_key psi_key)
{
  bool deleted;
  uint length= build_table_filename(path, path_length-1,
                                    db->str, name->str, ext, 0);
  path[length]= '~';
  path[length+1]= 0;
  deleted= mysql_file_delete(psi_key, path, MYF(0)) != 0;
  path[length]= 0;
  return deleted;
}


static LEX_CSTRING end_comment=
{ STRING_WITH_LEN(" /* generated by ddl recovery */")};


/**
  Log DROP query to binary log with comment

  This function is only run during recovery
*/

static void ddl_log_to_binary_log(THD *thd, String *query)
{
  LEX_CSTRING thd_db= thd->db;

  lex_string_set(&thd->db, recovery_state.current_db);
  query->length(query->length()-1);             // Removed end ','
  query->append(&end_comment);
  mysql_mutex_unlock(&LOCK_gdl);
  (void) thd->binlog_query(THD::STMT_QUERY_TYPE,
                           query->ptr(), query->length(),
                           TRUE, FALSE, FALSE, 0);
  mysql_mutex_lock(&LOCK_gdl);
  thd->db= thd_db;
}


/**
   Log DROP TABLE/VIEW to binary log when needed

   @result 0  Nothing was done
   @result 1  Query was logged to binary log & query was reset

   Logging happens in the following cases
   - This is the last DROP entry
   - The query could be longer than max_packet_length if we would add another
     table name to the query

   When we log, we always log all found tables and views at the same time. This
   is done to simplify the execute code as otherwise we would have to keep
   information of what was logged.
*/

static bool ddl_log_drop_to_binary_log(THD *thd, DDL_LOG_ENTRY *ddl_log_entry,
                                  String *query)
{
  DBUG_ENTER("ddl_log_drop_to_binary_log");
  if (mysql_bin_log.is_open())
  {
    if (!ddl_log_entry->next_entry ||
        query->length() + end_comment.length + NAME_LEN + 100 >
        thd->variables.max_allowed_packet)
    {
      if (recovery_state.drop_table.length() >
          recovery_state.drop_table_init_length)
      {
        ddl_log_to_binary_log(thd, &recovery_state.drop_table);
        recovery_state.drop_table.length(recovery_state.drop_table_init_length);
      }
      if (recovery_state.drop_view.length() >
          recovery_state.drop_view_init_length)
      {
        ddl_log_to_binary_log(thd, &recovery_state.drop_view);
        recovery_state.drop_view.length(recovery_state.drop_view_init_length);
      }
      DBUG_RETURN(1);
    }
  }
  DBUG_RETURN(0);
}

/*
  Create a new handler based on handlerton name
*/

static handler *create_handler(THD *thd, MEM_ROOT *mem_root,
                               LEX_CSTRING *name)
{
  handlerton *hton;
  handler *file;
  plugin_ref plugin= my_plugin_lock_by_name(thd, name,
                                            MYSQL_STORAGE_ENGINE_PLUGIN);
  if (!plugin)
  {
    my_error(ER_UNKNOWN_STORAGE_ENGINE, MYF(ME_ERROR_LOG), name->str);
    return 0;
  }
  hton= plugin_hton(plugin);
  if (!ha_storage_engine_is_enabled(hton))
  {
    my_error(ER_STORAGE_ENGINE_DISABLED, MYF(ME_ERROR_LOG), name->str);
    return 0;
  }
  if ((file= hton->create(hton, (TABLE_SHARE*) 0, mem_root)))
    file->init();
  return file;
}


/*
  Rename a table and its .frm file for a ddl_log_entry

  We first rename the table and then the .frm file as some engines,
  like connect, needs the .frm file to exists to be able to do an rename.
*/

static void execute_rename_table(THD *thd, DDL_LOG_ENTRY *ddl_log_entry,
                                 handler *file,
                                 const LEX_CSTRING *from_db,
                                 const LEX_CSTRING *from_table,
                                 const LEX_CSTRING *to_db,
                                 const LEX_CSTRING *to_table,
                                 uint flags,
                                 char *from_path, char *to_path)
{
  uint to_length=0, fr_length=0;
  DBUG_ENTER("execute_rename_table");

  if (file->needs_lower_case_filenames())
  {
    build_lower_case_table_filename(from_path, FN_REFLEN,
                                    from_db, from_table,
                                    flags & FN_FROM_IS_TMP);
    build_lower_case_table_filename(to_path, FN_REFLEN,
                                    to_db, to_table, flags & FN_TO_IS_TMP);
  }
  else
  {
    fr_length= build_table_filename(from_path, FN_REFLEN,
                                    from_db->str, from_table->str, "",
                                    flags & FN_FROM_IS_TMP);
    to_length= build_table_filename(to_path, FN_REFLEN,
                                    to_db->str, to_table->str, "",
                                    flags & FN_TO_IS_TMP);
  }

  uint keys, total_keys;

  if (!get_hlindex_keys_by_open(thd, from_db, from_table, from_path, &keys,
                                &total_keys))
  {
    char idx_from[FN_REFLEN + 1], idx_to[FN_REFLEN + 1];
    char *idx_from_end= strmov(idx_from, from_path);
    char *idx_to_end= strmov(idx_to, to_path);

    for (uint i= keys; i < total_keys; i++)
    {
      my_snprintf(idx_from_end, HLINDEX_BUF_LEN, HLINDEX_TEMPLATE, i);
      my_snprintf(idx_to_end, HLINDEX_BUF_LEN, HLINDEX_TEMPLATE, i);
      file->ha_rename_table(idx_from, idx_to);
    }
  }

  file->ha_rename_table(from_path, to_path);
  if (file->needs_lower_case_filenames())
  {
    /*
      We have to rebuild the file names as the .frm file should be used
      without lower case conversion
    */
    fr_length= build_table_filename(from_path, FN_REFLEN,
                                    from_db->str, from_table->str, reg_ext,
                                    flags & FN_FROM_IS_TMP);
    to_length= build_table_filename(to_path, FN_REFLEN,
                                    to_db->str, to_table->str, reg_ext,
                                    flags & FN_TO_IS_TMP);
  }
  else
  {
    strmov(from_path+fr_length, reg_ext);
    strmov(to_path+to_length,   reg_ext);
  }
  if (!access(from_path, F_OK))
    (void) mysql_file_rename(key_file_frm, from_path, to_path, MYF(MY_WME));
  DBUG_VOID_RETURN;
}


static int execute_drop_table(THD *thd, handlerton *hton, const LEX_CSTRING *db,
                              const LEX_CSTRING *table, const char *path)
{
  uint keys, total_keys;
  int error, first_error= 0;
  DBUG_ENTER("execute_drop_table");

  if (get_hlindex_keys_by_open(thd, db, table, path, &keys, &total_keys) == 0)
  {
    char idx_path[FN_REFLEN + 1];
    char *idx_path_end= strmov(idx_path, path);

    for (uint i= keys; i < total_keys; i++)
    {
      my_snprintf(idx_path_end, HLINDEX_BUF_LEN, HLINDEX_TEMPLATE, i);
      error= hton->drop_table(hton, idx_path);
      if (!non_existing_table_error(error) && !first_error)
        first_error= error;
    }
  }
  if (!first_error)
  {
    error= hton->drop_table(hton, path);
    if (!non_existing_table_error(error))
      first_error= error;
  }
  DBUG_RETURN(first_error);
}


/*
  Update triggers

  If swap_tables == 0  (Restoring the original in case of failed rename)
    Convert triggers for db.name -> from_db.from_name
  else (Doing the rename in case of ALTER TABLE ... RENAME)
    Convert triggers for from_db.from_name -> db.extra_name
*/

static void rename_triggers(THD *thd, DDL_LOG_ENTRY *ddl_log_entry,
                            bool swap_tables)
{
  Lex_ident_table to_table, from_table, from_converted_name;
  Lex_ident_db to_db, from_db;
  char to_path[FN_REFLEN+1], from_path[FN_REFLEN+1], conv_path[FN_REFLEN+1];

  if (!swap_tables)
  {
    from_db=    Lex_ident_db(ddl_log_entry->db);
    from_table= Lex_ident_table(ddl_log_entry->name);
    to_db=      Lex_ident_db(ddl_log_entry->from_db);
    to_table=   Lex_ident_table(ddl_log_entry->from_name);
  }
  else
  {
    from_db=    Lex_ident_db(ddl_log_entry->from_db);
    from_table= Lex_ident_table(ddl_log_entry->from_name);
    to_db=      Lex_ident_db(ddl_log_entry->db);
    to_table=   Lex_ident_table(ddl_log_entry->extra_name);
  }

  build_filename_and_delete_tmp_file(from_path, sizeof(from_path),
                                     &from_db, &from_table,
                                     TRG_EXT, key_file_trg);
  build_filename_and_delete_tmp_file(to_path, sizeof(to_path),
                                     &to_db, &to_table,
                                     TRG_EXT, key_file_trg);
  if (lower_case_table_names)
  {
    uint errors;
    from_converted_name.str= conv_path;
    from_converted_name.length=
      strconvert(system_charset_info, from_table.str, from_table.length,
                 files_charset_info, conv_path, FN_REFLEN, &errors);
  }
  else
    from_converted_name= from_table;

  if (!access(to_path, F_OK))
  {
    /*
      The original file was never renamed or we crashed in recovery
      just after renaming back the file.
      In this case the current file is correct and we can remove any
      left over copied files
    */
    (void) mysql_file_delete(key_file_trg, from_path, MYF(0));
  }
  else if (!access(from_path, F_OK))
  {
    /* .TRG file was renamed. Rename it back */
    /*
      We have to create a MDL lock as change_table_names() checks that we
      have a mdl locks for the table
    */
    MDL_request mdl_request;
    TRIGGER_RENAME_PARAM trigger_param;
    int error __attribute__((unused));
    MDL_REQUEST_INIT(&mdl_request, MDL_key::TABLE,
                     from_db.str,
                     from_converted_name.str,
                     MDL_EXCLUSIVE, MDL_EXPLICIT);
    error= thd->mdl_context.acquire_lock(&mdl_request, 1);
    /* acquire_locks() should never fail during recovery */
    DBUG_ASSERT(error == 0);

    (void) Table_triggers_list::prepare_for_rename(thd,
                                                   &trigger_param,
                                                   from_db,
                                                   from_table,
                                                   from_converted_name,
                                                   to_db,
                                                   to_table);
    (void) Table_triggers_list::change_table_name(thd,
                                                  &trigger_param,
                                                  &from_db,
                                                  &from_table,
                                                  &from_converted_name,
                                                  &to_db,
                                                  &to_table);
    thd->mdl_context.release_lock(mdl_request.ticket);
  }
}


/*
  Update stat tables

  If swap_tables == 0
    Convert stats for from_db.from_table -> db.name
  else
    Convert stats for db.name -> from_db.from_table
*/

static void rename_in_stat_tables(THD *thd, DDL_LOG_ENTRY *ddl_log_entry,
                                  bool swap_tables)
{
  LEX_CSTRING from_table, to_table, from_db, to_db, from_converted_name;
  char conv_path[FN_REFLEN+1];

  if (!swap_tables)
  {
    from_db=    ddl_log_entry->db;
    from_table= ddl_log_entry->name;
    to_db=      ddl_log_entry->from_db;
    to_table=   ddl_log_entry->from_name;
  }
  else
  {
    from_db=    ddl_log_entry->from_db;
    from_table= ddl_log_entry->from_name;
    to_db=      ddl_log_entry->db;
    to_table=   ddl_log_entry->extra_name;
  }
  if (lower_case_table_names)
  {
    uint errors;
    from_converted_name.str= conv_path;
    from_converted_name.length=
      strconvert(system_charset_info, from_table.str, from_table.length,
                 files_charset_info, conv_path, FN_REFLEN, &errors);
  }
  else
    from_converted_name= from_table;

  (void) rename_table_in_stat_tables(thd,
                                     &from_db,
                                     &from_converted_name,
                                     &to_db,
                                     &to_table);
}


/**
  Execute one action in a ddl log entry

  @param ddl_log_entry              Information in action entry to execute

  @return Operation status
    @retval TRUE                       Error
    @retval FALSE                      Success
*/

static int ddl_log_execute_action(THD *thd, MEM_ROOT *mem_root,
                                  DDL_LOG_ENTRY *ddl_log_entry)
{
  LEX_CSTRING handler_name;
  handler *file= NULL;
  char to_path[FN_REFLEN+1], from_path[FN_REFLEN+1];
  handlerton *hton= 0;
  ddl_log_error_handler no_such_table_handler;
  uint entry_pos= ddl_log_entry->entry_pos;
  int error;
  bool frm_action= FALSE;
  DBUG_ENTER("ddl_log_execute_action");

  mysql_mutex_assert_owner(&LOCK_gdl);
  DBUG_PRINT("ddl_log",
             ("pos: %u=>%u->%u  type: %u  action: %u (%s) phase: %u  "
              "handler: '%s'  name: '%s'  from_name: '%s'  tmp_name: '%s'",
              recovery_state.execute_entry_pos,
              ddl_log_entry->entry_pos,
              ddl_log_entry->next_entry,
              (uint) ddl_log_entry->entry_type,
              (uint) ddl_log_entry->action_type,
              ddl_log_action_name[ddl_log_entry->action_type],
              (uint) ddl_log_entry->phase,
              ddl_log_entry->handler_name.str,
              ddl_log_entry->name.str,
              ddl_log_entry->from_name.str,
              ddl_log_entry->tmp_name.str));

  if (ddl_log_entry->entry_type == DDL_LOG_IGNORE_ENTRY_CODE ||
      ddl_log_entry->phase == DDL_LOG_FINAL_PHASE)
    DBUG_RETURN(FALSE);

  handler_name=    ddl_log_entry->handler_name;
  thd->push_internal_handler(&no_such_table_handler);

  if (!strcmp(ddl_log_entry->handler_name.str, reg_ext))
    frm_action= TRUE;
  else if (ddl_log_entry->handler_name.length)
  {
    if (!(file= create_handler(thd, mem_root, &handler_name)))
      goto end;
    hton= file->ht;
  }

  switch (ddl_log_entry->action_type) {
  case DDL_LOG_REPLACE_ACTION:
  case DDL_LOG_DELETE_ACTION:
  {
    if (ddl_log_entry->phase == 0)
    {
      if (frm_action)
      {
        strxmov(to_path, ddl_log_entry->name.str, reg_ext, NullS);
        if (unlikely((error= mysql_file_delete(key_file_frm, to_path,
                                               MYF(MY_WME |
                                                   MY_IGNORE_ENOENT)))))
          break;
#ifdef WITH_PARTITION_STORAGE_ENGINE
        strxmov(to_path, ddl_log_entry->name.str, PAR_EXT, NullS);
        (void) mysql_file_delete(key_file_partition_ddl_log, to_path,
                                 MYF(0));
#endif
      }
      else
      {
        if (unlikely((error= hton->drop_table(hton, ddl_log_entry->name.str))))
        {
          if (!non_existing_table_error(error))
            break;
        }
      }
      if (increment_phase(entry_pos))
        break;
      error= 0;
      if (ddl_log_entry->action_type == DDL_LOG_DELETE_ACTION)
        break;
    }
  }
  DBUG_ASSERT(ddl_log_entry->action_type == DDL_LOG_REPLACE_ACTION);
  /*
    Fall through and perform the rename action of the replace
    action. We have already indicated the success of the delete
    action in the log entry by stepping up the phase.
  */
  /* fall through */
  case DDL_LOG_RENAME_ACTION:
  {
    error= TRUE;
    if (frm_action)
    {
      strxmov(to_path, ddl_log_entry->name.str, reg_ext, NullS);
      strxmov(from_path, ddl_log_entry->from_name.str, reg_ext, NullS);
      (void) mysql_file_rename(key_file_frm, from_path, to_path, MYF(MY_WME));
#ifdef WITH_PARTITION_STORAGE_ENGINE
      strxmov(to_path, ddl_log_entry->name.str, PAR_EXT, NullS);
      strxmov(from_path, ddl_log_entry->from_name.str, PAR_EXT, NullS);
      (void) mysql_file_rename(key_file_partition_ddl_log, from_path, to_path,
                               MYF(MY_WME));
#endif
    }
    else
      (void) file->ha_rename_table(ddl_log_entry->from_name.str,
                                   ddl_log_entry->name.str);
    if (increment_phase(entry_pos))
      break;
    break;
  }
  case DDL_LOG_EXCHANGE_ACTION:
  {
    /* We hold LOCK_gdl, so we can alter global_ddl_log.file_entry_buf */
    uchar *file_entry_buf= global_ddl_log.file_entry_buf;
    /* not yet implemented for frm */
    DBUG_ASSERT(!frm_action);
    /*
      Using a case-switch here to revert all currently done phases,
      since it will fall through until the first phase is undone.
    */
    switch (ddl_log_entry->phase) {
    case EXCH_PHASE_TEMP_TO_FROM:
      /* tmp_name -> from_name possibly done */
      (void) file->ha_rename_table(ddl_log_entry->from_name.str,
                                   ddl_log_entry->tmp_name.str);
      /* decrease the phase and sync */
      file_entry_buf[DDL_LOG_PHASE_POS]--;
      if (write_ddl_log_file_entry(entry_pos))
        break;
      (void) ddl_log_sync_no_lock();
      /* fall through */
    case EXCH_PHASE_FROM_TO_NAME:
      /* from_name -> name possibly done */
      (void) file->ha_rename_table(ddl_log_entry->name.str,
                                   ddl_log_entry->from_name.str);
      /* decrease the phase and sync */
      file_entry_buf[DDL_LOG_PHASE_POS]--;
      if (write_ddl_log_file_entry(entry_pos))
        break;
      (void) ddl_log_sync_no_lock();
      /* fall through */
    case EXCH_PHASE_NAME_TO_TEMP:
      /* name -> tmp_name possibly done */
      (void) file->ha_rename_table(ddl_log_entry->tmp_name.str,
                                   ddl_log_entry->name.str);
      /* disable the entry and sync */
      file_entry_buf[DDL_LOG_ENTRY_TYPE_POS]= DDL_LOG_IGNORE_ENTRY_CODE;
      (void) write_ddl_log_file_entry(entry_pos);
      (void) ddl_log_sync_no_lock();
      break;
    }
    break;
  }
  case DDL_LOG_RENAME_TABLE_ACTION:
  {
    /*
      We should restore things by renaming from
      'entry->name' to 'entry->from_name'
    */
    switch (ddl_log_entry->phase) {
    case DDL_RENAME_PHASE_TRIGGER:
      rename_triggers(thd, ddl_log_entry, 0);
      if (increment_phase(entry_pos))
        break;
    /* fall through */
    case DDL_RENAME_PHASE_STAT:
      /*
        Stat tables must be updated last so that we can handle a rename of
        a stat table. For now we just remember that we have to update it
      */
      update_flags(ddl_log_entry->entry_pos, DDL_LOG_FLAG_UPDATE_STAT);
      ddl_log_entry->flags|= DDL_LOG_FLAG_UPDATE_STAT;
    /* fall through */
    case DDL_RENAME_PHASE_TABLE:
      /* Restore frm and table to original names */
      execute_rename_table(thd, ddl_log_entry, file,
                           &ddl_log_entry->db, &ddl_log_entry->name,
                           &ddl_log_entry->from_db, &ddl_log_entry->from_name,
                           0,
                           from_path, to_path);

      if (ddl_log_entry->flags & DDL_LOG_FLAG_UPDATE_STAT)
      {
        /* Update stat tables last */
        rename_in_stat_tables(thd, ddl_log_entry, 0);
      }

      /* disable the entry and sync */
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    default:
      DBUG_ASSERT(0);
      break;
    }
    break;
  }
  case DDL_LOG_RENAME_VIEW_ACTION:
  {
    LEX_CSTRING from_table, to_table;
    from_table= ddl_log_entry->from_name;
    to_table=   ddl_log_entry->name;

    /* Delete any left over .frm~ files */
    build_filename_and_delete_tmp_file(to_path, sizeof(to_path) - 1,
                                       &ddl_log_entry->db,
                                       &ddl_log_entry->name,
                                       reg_ext,
                                       key_file_fileparser);
    build_filename_and_delete_tmp_file(from_path, sizeof(from_path) - 1,
                                       &ddl_log_entry->from_db,
                                       &ddl_log_entry->from_name,
                                       reg_ext, key_file_fileparser);

    /* Rename view back if the original rename did succeed */
    if (!access(to_path, F_OK))
      (void) mysql_rename_view(thd,
                               &ddl_log_entry->from_db, &from_table,
                               &ddl_log_entry->db, &to_table);
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
  }
  break;
  /*
    Initialize variables for DROP TABLE and DROP VIEW
    In normal cases a query only contains one action. However in case of
    DROP DATABASE we may get a mix of both and we have to keep these
    separate.
  */
  case DDL_LOG_DROP_INIT_ACTION:
  {
    LEX_CSTRING *comment= &ddl_log_entry->tmp_name;
    recovery_state.drop_table.length(0);
    recovery_state.drop_table.set_charset(system_charset_info);
    recovery_state.drop_table.append(STRING_WITH_LEN("DROP TABLE IF EXISTS "));
    if (comment->length)
    {
      recovery_state.drop_table.append(comment);
      recovery_state.drop_table.append(' ');
    }
    recovery_state.drop_table_init_length= recovery_state.drop_table.length();

    recovery_state.drop_view.length(0);
    recovery_state.drop_view.set_charset(system_charset_info);
    recovery_state.drop_view.append(STRING_WITH_LEN("DROP VIEW IF EXISTS "));
    recovery_state.drop_view_init_length= recovery_state.drop_view.length();

    strmake(recovery_state.current_db,
            ddl_log_entry->from_db.str, sizeof(recovery_state.current_db)-1);
    /* We don't increment phase as we want to retry this in case of crash */
    break;
  }
  case DDL_LOG_DROP_TABLE_ACTION:
  {
    LEX_CSTRING db, table, path;
    db=     ddl_log_entry->db;
    table=  ddl_log_entry->name;
    /* Note that path is without .frm extension */
    path=   ddl_log_entry->tmp_name;

    switch (ddl_log_entry->phase) {
    case DDL_DROP_PHASE_TABLE:
      if (hton)
      {
        no_such_table_handler.only_ignore_non_existing_errors= 1;
        error= execute_drop_table(thd, hton, &db, &table, path.str);
        no_such_table_handler.only_ignore_non_existing_errors= 0;
        if (error)
          break;
      }
      else
        error= ha_delete_table_force(thd, path.str, &db, &table);
      if (error <= 0)
      {
        /* Not found or already deleted. Delete .frm if it exists */
        strxnmov(to_path, sizeof(to_path)-1, path.str, reg_ext, NullS);
        mysql_file_delete(key_file_frm, to_path, MYF(MY_WME|MY_IGNORE_ENOENT));
        error= 0;
      }
      if (increment_phase(entry_pos))
        break;
      /* Fall through */
    case DDL_DROP_PHASE_TRIGGER:
      Table_triggers_list::drop_all_triggers(thd, &db, &table,
                                             MYF(MY_WME | MY_IGNORE_ENOENT));
      if (increment_phase(entry_pos))
        break;
      /* Fall through */
    case DDL_DROP_PHASE_BINLOG:
      if (strcmp(recovery_state.current_db, db.str))
      {
        append_identifier(thd, &recovery_state.drop_table, &db);
        recovery_state.drop_table.append('.');
      }
      append_identifier(thd, &recovery_state.drop_table, &table);
      recovery_state.drop_table.append(',');
      /* We don't increment phase as we want to retry this in case of crash */

      if (ddl_log_drop_to_binary_log(thd, ddl_log_entry,
                                     &recovery_state.drop_table))
      {
        if (increment_phase(entry_pos))
          break;
      }
      break;
    case DDL_DROP_PHASE_RESET:
      /* We have already logged all previous drop's. Clear the query */
      recovery_state.drop_table.length(recovery_state.drop_table_init_length);
      recovery_state.drop_view.length(recovery_state.drop_view_init_length);
      break;
    }
    break;
  }
  case DDL_LOG_DROP_VIEW_ACTION:
  {
    LEX_CSTRING db, table, path;
    db=     ddl_log_entry->db;
    table=  ddl_log_entry->name;
    /* Note that for views path is WITH .frm extension */
    path=   ddl_log_entry->tmp_name;

    if (ddl_log_entry->phase == 0)
    {
      mysql_file_delete(key_file_frm, path.str, MYF(MY_WME|MY_IGNORE_ENOENT));
      if (strcmp(recovery_state.current_db, db.str))
      {
        append_identifier(thd, &recovery_state.drop_view, &db);
        recovery_state.drop_view.append('.');
      }
      append_identifier(thd, &recovery_state.drop_view, &table);
      recovery_state.drop_view.append(',');

      if (ddl_log_drop_to_binary_log(thd, ddl_log_entry,
                                     &recovery_state.drop_view))
      {
        if (increment_phase(entry_pos))
          break;
      }
    }
    else
    {
      /* We have already logged all previous drop's. Clear the query */
      recovery_state.drop_table.length(recovery_state.drop_table_init_length);
      recovery_state.drop_view.length(recovery_state.drop_table_init_length);
    }
    break;
  }
  case DDL_LOG_DROP_TRIGGER_ACTION:
  {
    MY_STAT stat_info;
    off_t frm_length= 1;                        // Impossible length
    LEX_CSTRING thd_db= thd->db;

    /* Delete trigger temporary file if it still exists */
    if (!build_filename_and_delete_tmp_file(to_path, sizeof(to_path) - 1,
                                            &ddl_log_entry->db,
                                            &ddl_log_entry->name,
                                            TRG_EXT,
                                            key_file_fileparser))
    {
      /* Temporary file existed and was deleted, nothing left to do */
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    /*
      We can use length of TRG file as an indication if trigger was removed.
      If there is no file, then it means that this was the last trigger
      and the file was removed.
     */
    if (my_stat(to_path, &stat_info, MYF(0)))
      frm_length= (off_t) stat_info.st_size;
    if (frm_length != (off_t) ddl_log_entry->unique_id &&
        mysql_bin_log.is_open())
    {
      /*
        File size changed and it was not binlogged (as this entry was
        executed)
      */
      (void) rm_trigname_file(to_path, &ddl_log_entry->db,
                              &ddl_log_entry->from_name,
                              MYF(0));

      recovery_state.drop_table.length(0);
      recovery_state.drop_table.set_charset(system_charset_info);
      if (ddl_log_entry->tmp_name.length)
      {
        /* We can use the original query */
        recovery_state.drop_table.append(&ddl_log_entry->tmp_name);
      }
      else
      {
        /* Generate new query */
        recovery_state.drop_table.append(STRING_WITH_LEN("DROP TRIGGER IF "
                                                         "EXISTS "));
        append_identifier(thd, &recovery_state.drop_table,
                          &ddl_log_entry->from_name);
        recovery_state.drop_table.append(&end_comment);
      }
      if (mysql_bin_log.is_open())
      {
        mysql_mutex_unlock(&LOCK_gdl);
        thd->db= ddl_log_entry->db;
        (void) thd->binlog_query(THD::STMT_QUERY_TYPE,
                                 recovery_state.drop_table.ptr(),
                                 recovery_state.drop_table.length(), TRUE, FALSE,
                                 FALSE, 0);
        thd->db= thd_db;
        mysql_mutex_lock(&LOCK_gdl);
      }
    }
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
    break;
  }
  case DDL_LOG_DROP_DB_ACTION:
  {
    LEX_CSTRING db, path;
    db=     ddl_log_entry->db;
    path=   ddl_log_entry->tmp_name;

    switch (ddl_log_entry->phase) {
    case DDL_DROP_DB_PHASE_INIT:
      drop_database_objects(thd, &path, &db, MYSQL_SCHEMA_NAME.streq(db));

      strxnmov(to_path, sizeof(to_path)-1, path.str, MY_DB_OPT_FILE, NullS);
      mysql_file_delete_with_symlink(key_file_misc, to_path, "", MYF(0));

      (void) rm_dir_w_symlink(path.str, 0);
      if (increment_phase(entry_pos))
        break;
      /* fall through */
    case DDL_DROP_DB_PHASE_LOG:
    {
      String *query= &recovery_state.drop_table;

      query->length(0);
      query->append(STRING_WITH_LEN("DROP DATABASE IF EXISTS "));
      append_identifier(thd, query, &db);
      query->append(&end_comment);

      if (mysql_bin_log.is_open())
      {
        mysql_mutex_unlock(&LOCK_gdl);
        (void) thd->binlog_query(THD::STMT_QUERY_TYPE,
                                 query->ptr(), query->length(),
                                 TRUE, FALSE, FALSE, 0);
        mysql_mutex_lock(&LOCK_gdl);
      }
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    }
    break;
  }
  case DDL_LOG_CREATE_TABLE_ACTION:
  {
    LEX_CSTRING db, table, path;
    db=     ddl_log_entry->db;
    table=  ddl_log_entry->name;
    path=   ddl_log_entry->tmp_name;

    /* Don't delete the table if we didn't create it */
    if (ddl_log_entry->flags == 0)
    {
      if (hton)
        error= execute_drop_table(thd, hton, &db, &table, path.str);
      else
        error= ha_delete_table_force(thd, path.str, &db, &table);
    }
    strxnmov(to_path, sizeof(to_path)-1, path.str, reg_ext, NullS);
    mysql_file_delete(key_file_frm, to_path, MYF(MY_WME|MY_IGNORE_ENOENT));
    if (ddl_log_entry->phase == DDL_CREATE_TABLE_PHASE_LOG)
    {
      /*
        The server logged CREATE TABLE ... SELECT into binary log
        before crashing. As the commit failed and we have delete the
        table above, we have now to log the DROP of the created table.
      */

      String *query= &recovery_state.drop_table;
      query->length(0);
      query->append(STRING_WITH_LEN("DROP TABLE IF EXISTS "));
      append_identifier(thd, query, &db);
      query->append('.');
      append_identifier(thd, query, &table);
      query->append(&end_comment);

      if (mysql_bin_log.is_open())
      {
        mysql_mutex_unlock(&LOCK_gdl);
        (void) thd->binlog_query(THD::STMT_QUERY_TYPE,
                                 query->ptr(), query->length(),
                                 TRUE, FALSE, FALSE, 0);
        mysql_mutex_lock(&LOCK_gdl);
      }
    }
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
    error= 0;
    break;
  }
  case DDL_LOG_CREATE_VIEW_ACTION:
  {
    char *path= to_path;
    size_t path_length= ddl_log_entry->tmp_name.length;
    memcpy(path, ddl_log_entry->tmp_name.str, path_length+1);
    path[path_length+1]= 0;               // Prepare for extending

    /* Remove temporary parser file */
    path[path_length]='~';
    mysql_file_delete(key_file_fileparser, path,
                      MYF(MY_WME|MY_IGNORE_ENOENT));
    path[path_length]= 0;

    switch (ddl_log_entry->phase) {
    case DDL_CREATE_VIEW_PHASE_NO_OLD_VIEW:
    {
      /*
        No old view exists, so we can just delete the .frm and temporary files
      */
      path[path_length]='-';
      mysql_file_delete(key_file_fileparser, path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      path[path_length]= 0;
      mysql_file_delete(key_file_frm, path, MYF(MY_WME|MY_IGNORE_ENOENT));
      break;
    }
    case DDL_CREATE_VIEW_PHASE_DELETE_VIEW_COPY:
    {
      /*
        Old view existed. We crashed before we had done a copy and change
        state to DDL_CREATE_VIEW_PHASE_OLD_VIEW_COPIED
      */
      path[path_length]='-';
      mysql_file_delete(key_file_fileparser, path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      path[path_length]= 0;
      break;
    }
    case DDL_CREATE_VIEW_PHASE_OLD_VIEW_COPIED:
    {
      /*
        Old view existed copied to '-' file. Restore it
      */
      memcpy(from_path, path, path_length+2);
      from_path[path_length]='-';
      if (!access(from_path, F_OK))
        mysql_file_rename(key_file_fileparser, from_path, path, MYF(MY_WME));
      break;
    }
    }
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
    break;
  }
  case DDL_LOG_DELETE_TMP_FILE_ACTION:
  {
    LEX_CSTRING path= ddl_log_entry->tmp_name;
    DBUG_ASSERT(ddl_log_entry->unique_id <= UINT_MAX32);
    if (!ddl_log_entry->unique_id ||
        !is_execute_entry_active((uint) ddl_log_entry->unique_id))
      mysql_file_delete(key_file_fileparser, path.str,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
    break;
  }
  case DDL_LOG_CREATE_TRIGGER_ACTION:
  {
    LEX_CSTRING db, table, trigger;
    db=      ddl_log_entry->db;
    table=   ddl_log_entry->name;
    trigger= ddl_log_entry->tmp_name;

    /* Delete backup .TRG (trigger file) if it exists */
    (void) build_filename_and_delete_tmp_file(to_path, sizeof(to_path) - 1,
                                              &db, &table,
                                              TRG_EXT,
                                              key_file_fileparser);
    (void) build_filename_and_delete_tmp_file(to_path, sizeof(to_path) - 1,
                                              &db, &trigger,
                                              TRN_EXT,
                                              key_file_fileparser);
    switch (ddl_log_entry->phase) {
    case DDL_CREATE_TRIGGER_PHASE_DELETE_COPY:
    {
      size_t length;
      /* Delete copy of .TRN and .TRG files */
      length= build_table_filename(to_path, sizeof(to_path) - 1,
                                   db.str, table.str, TRG_EXT, 0);
      to_path[length]= '-';
      to_path[length+1]= 0;
      mysql_file_delete(key_file_fileparser, to_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));

      length= build_table_filename(to_path, sizeof(to_path) - 1,
                                   db.str, trigger.str, TRN_EXT, 0);
      to_path[length]= '-';
      to_path[length+1]= 0;
      mysql_file_delete(key_file_fileparser, to_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
    }
    /* Nothing else to do */
    (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
    break;
    case DDL_CREATE_TRIGGER_PHASE_OLD_COPIED:
    {
      LEX_CSTRING path= {to_path, 0};
      size_t length;
      /* Restore old version if the .TRN and .TRG files */
      length= build_table_filename(to_path, sizeof(to_path) - 1,
                                   db.str, table.str, TRG_EXT, 0);
      to_path[length]='-';
      to_path[length+1]= 0;
      path.length= length+1;
      /* an old TRN file only exist in the case if REPLACE was used */
      if (!access(to_path, F_OK))
        sql_restore_definition_file(&path);

      length= build_table_filename(to_path, sizeof(to_path) - 1,
                                   db.str, trigger.str, TRN_EXT, 0);
      to_path[length]='-';
      to_path[length+1]= 0;
      path.length= length+1;
      if (!access(to_path, F_OK))
        sql_restore_definition_file(&path);
      else
      {
        /*
          There was originally no .TRN for this trigger.
          Delete the newly created one.
        */
        to_path[length]= 0;
        mysql_file_delete(key_file_fileparser, to_path,
                          MYF(MY_WME|MY_IGNORE_ENOENT));
      }
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    case DDL_CREATE_TRIGGER_PHASE_NO_OLD_TRIGGER:
    {
      /* No old trigger existed. We can just delete the .TRN and .TRG files */
      build_table_filename(to_path, sizeof(to_path) - 1,
                           db.str, table.str, TRG_EXT, 0);
      mysql_file_delete(key_file_fileparser, to_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      build_table_filename(to_path, sizeof(to_path) - 1,
                           db.str, trigger.str, TRN_EXT, 0);
      mysql_file_delete(key_file_fileparser, to_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    }
    break;
  }
  case DDL_LOG_ALTER_TABLE_ACTION:
  {
    handlerton *org_hton, *partition_hton;
    handler *org_file;
    bool is_renamed= ddl_log_entry->flags & DDL_LOG_FLAG_ALTER_RENAME;
    bool new_version_ready= 0, new_version_unusable= 0;
    LEX_CSTRING db, table;
    db=     ddl_log_entry->db;
    table=  ddl_log_entry->name;

    if (!(org_file= create_handler(thd, mem_root,
                                   &ddl_log_entry->from_handler_name)))
      goto end;
    /* Handlerton of the final table and any temporary tables */
    org_hton= org_file->ht;
    /*
      partition_hton is the hton for the new file, or
      in case of ALTER of a partitioned table, the underlying
      table
    */
    partition_hton= hton;

    if (ddl_log_entry->flags & DDL_LOG_FLAG_ALTER_PARTITION)
    {
      /*
        The from and to tables where both using the partition engine.
      */
      hton= org_hton;
    }
    switch (ddl_log_entry->phase) {
    case DDL_ALTER_TABLE_PHASE_RENAME_FAILED:
      /*
        We come here when the final rename of temporary table (#sql-alter) to
        the original name failed. Now we have to delete the temporary table
        and restore the backup.
      */
      quick_rm_table(thd, hton, &db, &table, QRMT_DEFAULT | FN_IS_TMP);
      if (!is_renamed)
      {
        execute_rename_table(thd, ddl_log_entry, file,
                             &ddl_log_entry->from_db,
                             &ddl_log_entry->extra_name, // #sql-backup
                             &ddl_log_entry->from_db,
                             &ddl_log_entry->from_name,
                             FN_FROM_IS_TMP,
                             from_path, to_path);
      }
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    case DDL_ALTER_TABLE_PHASE_PREPARE_INPLACE:
      /* We crashed before ddl_log_update_unique_id() was called */
      new_version_unusable= 1;
      /* fall through */
    case DDL_ALTER_TABLE_PHASE_INPLACE_COPIED:
      /* The inplace alter table is committed and ready to be used */
      if (!new_version_unusable)
        new_version_ready= 1;
    /* fall through */
    case DDL_ALTER_TABLE_PHASE_INPLACE:
    {
      int fr_length, to_length;
      /*
        Inplace alter table was used.
        On disk there are now a table with the original name, the
        original .frm file and potentially a #sql-alter...frm file
        with the new definition.
      */
      fr_length= build_table_filename(from_path, sizeof(from_path) - 1,
                                      ddl_log_entry->db.str,
                                      ddl_log_entry->name.str,
                                      reg_ext, 0);
      to_length= build_table_filename(to_path, sizeof(to_path) - 1,
                                      ddl_log_entry->from_db.str,
                                      ddl_log_entry->from_name.str,
                                      reg_ext, 0);
      if (!access(from_path, F_OK))             // Does #sql-alter.. exists?
      {
        LEX_CUSTRING version= {ddl_log_entry->uuid, MY_UUID_SIZE};
        /*
          Temporary .frm file exists.  This means that that the table in
          the storage engine can be of either old or new version.
          If old version, delete the new .frm table and keep the old one.
          If new version, replace the old .frm with the new one.
        */
        to_path[to_length - reg_ext_length]= 0;  // Remove .frm
        if (!new_version_unusable &&
            ( !partition_hton->check_version || new_version_ready ||
              !partition_hton->check_version(partition_hton,
                                             to_path, &version,
                                             ddl_log_entry->unique_id)))
        {
          /* Table is up to date */

          /*
            Update state so that if we crash and retry the ddl log entry,
            we know that we can use the new table even if .frm is renamed.
          */
          if (ddl_log_entry->phase != DDL_ALTER_TABLE_PHASE_INPLACE_COPIED)
            (void) update_phase(entry_pos,
                                DDL_ALTER_TABLE_PHASE_INPLACE_COPIED);
          /* Replace old .frm file with new one */
          to_path[to_length - reg_ext_length]= FN_EXTCHAR;
          (void) mysql_file_rename(key_file_frm, from_path, to_path,
                                   MYF(MY_WME));
          new_version_ready= 1;
        }
        else
        {
          DBUG_ASSERT(!new_version_ready);
          /*
            Use original version of the .frm file.
            Remove temporary #sql-alter.frm file and the #sql-alter table.
            We have also to remove the temporary table as some storage engines,
            like InnoDB, may use it as an internal temporary table
            during inplace alter table.
          */
          from_path[fr_length - reg_ext_length]= 0;
          error= org_hton->drop_table(org_hton, from_path);
          if (non_existing_table_error(error))
            error= 0;
          from_path[fr_length - reg_ext_length]= FN_EXTCHAR;
          mysql_file_delete(key_file_frm, from_path,
                            MYF(MY_WME|MY_IGNORE_ENOENT));
          (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
          break;
        }
      }
      if (is_renamed && new_version_ready)
      {
        /* After the renames above, the original table is now in from_name */
        ddl_log_entry->name= ddl_log_entry->from_name;
        /* Rename db.name -> db.extra_name */
        execute_rename_table(thd, ddl_log_entry, file,
                             &ddl_log_entry->db, &ddl_log_entry->name,
                             &ddl_log_entry->db, &ddl_log_entry->extra_name,
                             0,
                             from_path, to_path);
      }
      (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_UPDATE_TRIGGERS);
      goto update_triggers;
    }
    case DDL_ALTER_TABLE_PHASE_COPIED:
    {
      char *from_end;
      /*
        New table is created and we have the query for the binary log.
        We should remove the original table and in the next stage replace
        it with the new one.
      */
      build_table_filename(from_path, sizeof(from_path) - 1,
                           ddl_log_entry->from_db.str,
                           ddl_log_entry->from_name.str,
                           "", 0);
      build_table_filename(to_path, sizeof(to_path) - 1,
                           ddl_log_entry->db.str,
                           ddl_log_entry->name.str,
                           "", 0);
      from_end= strend(from_path);
      if (likely(org_hton))
      {
        error= execute_drop_table(thd, org_hton, &ddl_log_entry->from_db,
                                  &ddl_log_entry->from_name, from_path);
      }
      strmov(from_end, reg_ext);
      mysql_file_delete(key_file_frm, from_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      *from_end= 0;                             // Remove extension

      (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_OLD_RENAMED);
    }
    /* fall through */
    case DDL_ALTER_TABLE_PHASE_OLD_RENAMED:
    {
      /*
        The new table (from_path) is up to date.
        Original table is either renamed as backup table (normal case),
        only frm is renamed (in case of engine change) or deleted above.
      */
      if (!is_renamed)
      {
        uint length;
        /* Rename new "temporary" table to the original wanted name */
        execute_rename_table(thd, ddl_log_entry, file,
                             &ddl_log_entry->db,
                             &ddl_log_entry->name,
                             &ddl_log_entry->from_db,
                             &ddl_log_entry->from_name,
                             FN_FROM_IS_TMP,
                             from_path, to_path);

        /*
          Remove backup (only happens if alter table used without rename).
          Backup name is always in lower case, so there is no need for
          converting table names.
        */
        length= build_table_filename(from_path, sizeof(from_path) - 1,
                                     ddl_log_entry->from_db.str,
                                     ddl_log_entry->extra_name.str,
                                     "", FN_IS_TMP);
        if (likely(org_hton))
        {
          if (ddl_log_entry->flags & DDL_LOG_FLAG_ALTER_ENGINE_CHANGED)
          {
            /* Only frm is renamed, storage engine files have original name */
            build_table_filename(to_path, sizeof(from_path) - 1,
                                 ddl_log_entry->from_db.str,
                                 ddl_log_entry->from_name.str,
                                 "", 0);
            error= execute_drop_table(thd, org_hton, &ddl_log_entry->from_db,
                                      &ddl_log_entry->from_name, to_path);
          }
          else
            error= execute_drop_table(thd, org_hton, &ddl_log_entry->from_db,
                                      &ddl_log_entry->from_name, from_path);
        }
        strmov(from_path + length, reg_ext);
        mysql_file_delete(key_file_frm, from_path,
                          MYF(MY_WME|MY_IGNORE_ENOENT));
      }
      else
        execute_rename_table(thd, ddl_log_entry, file,
                             &ddl_log_entry->db, &ddl_log_entry->name,
                             &ddl_log_entry->db, &ddl_log_entry->extra_name,
                             FN_FROM_IS_TMP,
                             from_path, to_path);
      (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_UPDATE_TRIGGERS);
    }
    /* fall through */
    case DDL_ALTER_TABLE_PHASE_UPDATE_TRIGGERS:
    update_triggers:
    {
      if (is_renamed)
      {
        // rename_triggers will rename from: from_db.from_name -> db.extra_name
        rename_triggers(thd, ddl_log_entry, 1);
        (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_UPDATE_STATS);
      }
    }
    /* fall through */
    case DDL_ALTER_TABLE_PHASE_UPDATE_STATS:
      if (is_renamed)
      {
        ddl_log_entry->name= ddl_log_entry->from_name;
        ddl_log_entry->from_name= ddl_log_entry->extra_name;
        rename_in_stat_tables(thd, ddl_log_entry, 1);
        (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_UPDATE_STATS);
      }
      /* fall through */
    case DDL_ALTER_TABLE_PHASE_UPDATE_BINARY_LOG:
    {
      /* Write ALTER TABLE query to binary log */
      if (recovery_state.query.length() && mysql_bin_log.is_open())
      {
        LEX_CSTRING save_db;
        /* Reuse old xid value if possible */
        if (!recovery_state.xid)
          recovery_state.xid= server_uuid_value();
        thd->binlog_xid= recovery_state.xid;
        update_xid(recovery_state.execute_entry_pos, thd->binlog_xid);

        mysql_mutex_unlock(&LOCK_gdl);
        save_db= thd->db;
        thd->db= recovery_state.db.to_lex_cstring();
        (void) thd->binlog_query(THD::STMT_QUERY_TYPE,
                                 recovery_state.query.ptr(),
                                 recovery_state.query.length(),
                                 TRUE, FALSE, FALSE, 0);
        thd->binlog_xid= 0;
        thd->db= save_db;
        mysql_mutex_lock(&LOCK_gdl);
      }
      recovery_state.query.length(0);
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    /*
      The following cases are when alter table failed and we have to roll
      back
    */
    case DDL_ALTER_TABLE_PHASE_CREATED:
    {
      /*
        Temporary table should have been created. Delete it.
      */
      if (likely(hton))
      {
        error= execute_drop_table(thd, hton, &ddl_log_entry->from_db,
                                  &ddl_log_entry->from_name,
                                  ddl_log_entry->tmp_name.str);
      }
      (void) update_phase(entry_pos, DDL_ALTER_TABLE_PHASE_INIT);
    }
    /* fall through */
    case DDL_ALTER_TABLE_PHASE_INIT:
    {
      /*
        A temporary .frm and possible a .par files should have been created
      */
      strxmov(to_path, ddl_log_entry->tmp_name.str, reg_ext, NullS);
      mysql_file_delete(key_file_frm, to_path, MYF(MY_WME|MY_IGNORE_ENOENT));
      strxmov(to_path, ddl_log_entry->tmp_name.str, PAR_EXT, NullS);
      mysql_file_delete(key_file_partition_ddl_log, to_path,
                        MYF(MY_WME|MY_IGNORE_ENOENT));
      (void) update_phase(entry_pos, DDL_LOG_FINAL_PHASE);
      break;
    }
    }
    delete org_file;
    break;
  }
  case DDL_LOG_STORE_QUERY_ACTION:
  {
    /*
      Read query for next ddl command
    */
    if (ddl_log_entry->flags)
    {
      /*
        First QUERY event. Allocate query string.
        Query length is stored in unique_id
      */
      if (recovery_state.query.alloc((size_t) (ddl_log_entry->unique_id+1)))
        goto end;
      recovery_state.query.length(0);
      recovery_state.db.copy(ddl_log_entry->db.str, ddl_log_entry->db.length,
                             system_charset_info);
    }
    if (unlikely(recovery_state.query.length() +
                 ddl_log_entry->extra_name.length >
                 recovery_state.query.alloced_length()))
    {
      /* Impossible length. Ignore query */
      recovery_state.query.length(0);
      error= 1;
      my_error(ER_INTERNAL_ERROR, MYF(0),
               "DDL log: QUERY event has impossible length");
      break;
    }
    recovery_state.query.qs_append(&ddl_log_entry->extra_name);
    break;
  }
  default:
    DBUG_ASSERT(0);
    break;
  }

end:
  delete file;
  /* We are only interested in errors that where not ignored */
  if ((error= (no_such_table_handler.unhandled_errors > 0)))
    my_errno= no_such_table_handler.first_error;
  thd->pop_internal_handler();
  DBUG_RETURN(error);
}


/**
  Get a free entry in the ddl log

  @param[out] active_entry     A ddl log memory entry returned
  @param[out] write_header     Set to 1 if ddl log was enlarged

  @return Operation status
    @retval TRUE               Error
    @retval FALSE              Success
*/

static bool ddl_log_get_free_entry(DDL_LOG_MEMORY_ENTRY **active_entry)
{
  DDL_LOG_MEMORY_ENTRY *used_entry;
  DDL_LOG_MEMORY_ENTRY *first_used= global_ddl_log.first_used;
  DBUG_ENTER("ddl_log_get_free_entry");

  if (global_ddl_log.first_free == NULL)
  {
    if (!(used_entry= ((DDL_LOG_MEMORY_ENTRY*)
                       my_malloc(key_memory_DDL_LOG_MEMORY_ENTRY,
                                 sizeof(DDL_LOG_MEMORY_ENTRY), MYF(MY_WME)))))
    {
      sql_print_error("DDL_LOG: Failed to allocate memory for ddl log free "
                      "list");
      *active_entry= 0;
      DBUG_RETURN(TRUE);
    }
    global_ddl_log.num_entries++;
    used_entry->entry_pos= global_ddl_log.num_entries;
  }
  else
  {
    used_entry= global_ddl_log.first_free;
    global_ddl_log.first_free= used_entry->next_log_entry;
  }
  /*
    Move from free list to used list
  */
  used_entry->next_log_entry= first_used;
  used_entry->prev_log_entry= NULL;
  used_entry->next_active_log_entry= NULL;
  global_ddl_log.first_used= used_entry;
  if (first_used)
    first_used->prev_log_entry= used_entry;

  *active_entry= used_entry;
  DBUG_RETURN(FALSE);
}


/**
  Release a log memory entry.
  @param log_memory_entry                Log memory entry to release
*/

void ddl_log_release_memory_entry(DDL_LOG_MEMORY_ENTRY *log_entry)
{
  DDL_LOG_MEMORY_ENTRY *next_log_entry= log_entry->next_log_entry;
  DDL_LOG_MEMORY_ENTRY *prev_log_entry= log_entry->prev_log_entry;
  DBUG_ENTER("ddl_log_release_memory_entry");

  mysql_mutex_assert_owner(&LOCK_gdl);
  log_entry->next_log_entry= global_ddl_log.first_free;
  global_ddl_log.first_free= log_entry;

  if (prev_log_entry)
    prev_log_entry->next_log_entry= next_log_entry;
  else
    global_ddl_log.first_used= next_log_entry;
  if (next_log_entry)
    next_log_entry->prev_log_entry= prev_log_entry;
  // Ensure we get a crash if we try to access this link again.
  log_entry->next_active_log_entry= (DDL_LOG_MEMORY_ENTRY*) 0x1;
  DBUG_VOID_RETURN;
}


/**
  Execute one entry in the ddl log.

  Executing an entry means executing a linked list of actions.

  @param first_entry           Reference to first action in entry

  @return Operation status
    @retval TRUE               Error
    @retval FALSE              Success
*/

static bool ddl_log_execute_entry_no_lock(THD *thd, uint first_entry)
{
  DDL_LOG_ENTRY ddl_log_entry;
  uint read_entry= first_entry;
  MEM_ROOT mem_root;
  DBUG_ENTER("ddl_log_execute_entry_no_lock");

  mysql_mutex_assert_owner(&LOCK_gdl);
  init_sql_alloc(key_memory_gdl, &mem_root, TABLE_ALLOC_BLOCK_SIZE, 0,
                 MYF(MY_THREAD_SPECIFIC));
  do
  {
    if (read_ddl_log_entry(read_entry, &ddl_log_entry))
    {
      /* Error logged to error log. Continue with next log entry */
      break;
    }
    DBUG_ASSERT(ddl_log_entry.entry_type == DDL_LOG_ENTRY_CODE ||
                ddl_log_entry.entry_type == DDL_LOG_IGNORE_ENTRY_CODE);

    if (ddl_log_execute_action(thd, &mem_root, &ddl_log_entry))
    {
      uint action_type= ddl_log_entry.action_type;
      if (action_type >= DDL_LOG_LAST_ACTION)
        action_type= 0;

      /* Write to error log and continue with next log entry */
      sql_print_error("DDL_LOG: Got error %d when trying to execute action "
                      "for entry %u of type '%s'",
                      (int) my_errno, read_entry,
                      ddl_log_action_name[action_type]);
      break;
    }
    read_entry= ddl_log_entry.next_entry;
  } while (read_entry);

  free_root(&mem_root, MYF(0));
  DBUG_RETURN(FALSE);
}


/*
  External interface methods for the DDL log Module
  ---------------------------------------------------
*/

/**
  Write a ddl log entry.

  A careful write of the ddl log is performed to ensure that we can
  handle crashes occurring during CREATE and ALTER TABLE processing.

  @param ddl_log_entry         Information about log entry
  @param[out] entry_written    Entry information written into

  @return Operation status
    @retval TRUE               Error
    @retval FALSE              Success
*/

bool ddl_log_write_entry(DDL_LOG_ENTRY *ddl_log_entry,
                         DDL_LOG_MEMORY_ENTRY **active_entry)
{
  bool error;
  DBUG_ENTER("ddl_log_write_entry");

  *active_entry= 0;
  mysql_mutex_assert_owner(&LOCK_gdl);
  DBUG_ASSERT(global_ddl_log.open);
  if (unlikely(!global_ddl_log.open))
  {
    my_error(ER_INTERNAL_ERROR, MYF(0), "ddl log not initialized");
    DBUG_RETURN(TRUE);
  }

  ddl_log_entry->entry_type= DDL_LOG_ENTRY_CODE;
  set_global_from_ddl_log_entry(ddl_log_entry);
  if (ddl_log_get_free_entry(active_entry))
    DBUG_RETURN(TRUE);

  error= FALSE;
  DBUG_PRINT("ddl_log",
             ("pos: %u->%u  action: %u (%s) phase: %u  "
              "handler: '%s'  name: '%s'  from_name: '%s'  tmp_name: '%s'",
              (*active_entry)->entry_pos,
              (uint) ddl_log_entry->next_entry,
              (uint) ddl_log_entry->action_type,
              ddl_log_action_name[ddl_log_entry->action_type],
              (uint) ddl_log_entry->phase,
              ddl_log_entry->handler_name.str,
              ddl_log_entry->name.str,
              ddl_log_entry->from_name.str,
              ddl_log_entry->tmp_name.str));

  if (unlikely(write_ddl_log_file_entry((*active_entry)->entry_pos)))
  {
    sql_print_error("DDL_LOG: Failed to write entry %u",
                    (*active_entry)->entry_pos);
    ddl_log_release_memory_entry(*active_entry);
    *active_entry= 0;
    error= TRUE;
  }
  DBUG_RETURN(error);
}


/**
  @brief Write or update execute entry in the ddl log.

  @details An execute entry points to the first entry that should
  be executed during recovery. In some cases it's only written once,
  in other cases it's updated for each log entry to point to the new
  header for the list.

  When called, the previous log entries have already been written but not yet
  synched to disk.  We write a couple of log entries that describes
  action to perform.  This entries are set-up in a linked list,
  however only when an execute entry is put as the first entry these will be
  executed during recovery.

  @param first_entry               First entry in linked list of entries
                                   to execute.
  @param cond_entry                Check and don't execute if cond_entry is active
  @param[in,out] active_entry      Entry to execute, 0 = NULL if the entry
                                   is written first time and needs to be
                                   returned. In this case the entry written
                                   is returned in this parameter
  @return Operation status
    @retval TRUE                   Error
    @retval FALSE                  Success
*/

bool ddl_log_write_execute_entry(uint first_entry,
                                 uint cond_entry,
                                 DDL_LOG_MEMORY_ENTRY **active_entry)
{
  uchar *file_entry_buf= global_ddl_log.file_entry_buf;
  bool got_free_entry= 0;
  DBUG_ENTER("ddl_log_write_execute_entry");

  mysql_mutex_assert_owner(&LOCK_gdl);
  /*
    We haven't synched the log entries yet, we sync them now before
    writing the execute entry.
  */
  (void) ddl_log_sync_no_lock();
  bzero(file_entry_buf, global_ddl_log.io_size);

  file_entry_buf[DDL_LOG_ENTRY_TYPE_POS]= (uchar)DDL_LOG_EXECUTE_CODE;
  int4store(file_entry_buf + DDL_LOG_NEXT_ENTRY_POS, first_entry);
  int8store(file_entry_buf + DDL_LOG_ID_POS, ((ulonglong)cond_entry << DDL_LOG_RETRY_BITS));

  if (!(*active_entry))
  {
    if (ddl_log_get_free_entry(active_entry))
      DBUG_RETURN(TRUE);
    got_free_entry= TRUE;
  }
  DBUG_PRINT("ddl_log",
             ("pos: %u=>%u",
             (*active_entry)->entry_pos, first_entry));
  if (write_ddl_log_file_entry((*active_entry)->entry_pos))
  {
    sql_print_error("DDL_LOG: Error writing execute entry %u",
                    (*active_entry)->entry_pos);
    if (got_free_entry)
    {
      ddl_log_release_memory_entry(*active_entry);
      *active_entry= 0;
    }
    DBUG_RETURN(TRUE);
  }
  (void) ddl_log_sync_no_lock();
  DBUG_RETURN(FALSE);
}


/**
  Increment phase for entry. Will deactivate entry after all phases are done

  @details see ddl_log_increment_phase_no_lock.

  @param entry_pos     Entry position of record to change

  @return Operation status
    @retval TRUE      Error
    @retval FALSE     Success
*/

bool ddl_log_increment_phase(uint entry_pos)
{
  bool error;
  DBUG_ENTER("ddl_log_increment_phase");
  DBUG_PRINT("ddl_log", ("pos: %u", entry_pos));

  mysql_mutex_lock(&LOCK_gdl);
  error= ddl_log_increment_phase_no_lock(entry_pos);
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(error);
}


/**
  Sync ddl log file.

  @return Operation status
    @retval TRUE        Error
    @retval FALSE       Success
*/

bool ddl_log_sync()
{
  bool error;
  DBUG_ENTER("ddl_log_sync");

  mysql_mutex_lock(&LOCK_gdl);
  error= ddl_log_sync_no_lock();
  mysql_mutex_unlock(&LOCK_gdl);

  DBUG_RETURN(error);
}


/**
  Execute one entry in the ddl log.

  Executing an entry means executing a linked list of actions.

  This function is called for recovering partitioning in case of error.

  @param first_entry           Reference to first action in entry

  @return Operation status
    @retval TRUE               Error
    @retval FALSE              Success
*/

bool ddl_log_execute_entry(THD *thd, uint first_entry)
{
  bool error;
  DBUG_ENTER("ddl_log_execute_entry");

  mysql_mutex_lock(&LOCK_gdl);
  error= ddl_log_execute_entry_no_lock(thd, first_entry);
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(error);
}


/**
  Close the ddl log.
*/

static void close_ddl_log()
{
  DBUG_ENTER("close_ddl_log");
  if (global_ddl_log.file_id >= 0)
  {
    (void) mysql_file_close(global_ddl_log.file_id, MYF(MY_WME));
    global_ddl_log.file_id= (File) -1;
  }
  global_ddl_log.open= 0;
  DBUG_VOID_RETURN;
}


/**
  Loop over ddl log excute entries and mark those that are already stored
  in the binary log as completed

  @return
  @retval 0 ok
  @return 1 fail (write error)

*/

bool ddl_log_close_binlogged_events(HASH *xids)
{
  uint i;
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_close_binlogged_events");

  if (global_ddl_log.num_entries == 0 || xids->records == 0)
    DBUG_RETURN(0);

  mysql_mutex_lock(&LOCK_gdl);
  for (i= 1; i <= global_ddl_log.num_entries; i++)
  {
    if (read_ddl_log_entry(i, &ddl_log_entry))
      break;                                    // Read error. Stop reading
    DBUG_PRINT("xid",("xid: %llu", ddl_log_entry.xid));
    if (ddl_log_entry.entry_type == DDL_LOG_EXECUTE_CODE &&
        ddl_log_entry.xid != 0 &&
        my_hash_search(xids, (uchar*) &ddl_log_entry.xid,
                       sizeof(ddl_log_entry.xid)))
    {
      if (disable_execute_entry(i))
      {
        mysql_mutex_unlock(&LOCK_gdl);
        DBUG_RETURN(1);                         // Write error. Fatal!
      }
    }
  }
  (void) ddl_log_sync_no_lock();
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(0);
}


/**
  Execute the ddl log at recovery of MySQL Server.

  @return
  @retval 0     Ok.
  @retval > 0   Fatal error. We have to abort (can't create ddl log)
  @return < -1  Recovery failed, but new log exists and is usable

*/

int ddl_log_execute_recovery()
{
  uint i, count= 0;
  int error= 0;
  THD *thd, *original_thd;
  DDL_LOG_ENTRY ddl_log_entry;
  static char recover_query_string[]= "INTERNAL DDL LOG RECOVER IN PROGRESS";
  DBUG_ENTER("ddl_log_execute_recovery");

  if (!global_ddl_log.backup_done && !global_ddl_log.created)
    ddl_log_create_backup_file();

  if (global_ddl_log.num_entries == 0)
    DBUG_RETURN(0);

  /*
    To be able to run this from boot, we allocate a temporary THD
  */
  if (!(thd=new THD(0)))
  {
    DBUG_ASSERT(0);                             // Fatal error
    DBUG_RETURN(1);
  }
  original_thd= current_thd;                    // Probably NULL
  thd->store_globals();
  thd->init();                                  // Needed for error messages
  thd->set_query_inner((char*) STRING_WITH_LEN("intern:ddl_log_execute_recovery"),
                       default_charset_info);

  thd->log_all_errors= (global_system_variables.log_warnings >= 3);
  recovery_state.drop_table.free();
  recovery_state.drop_view.free();
  recovery_state.query.free();
  recovery_state.db.free();

  thd->set_query(recover_query_string, strlen(recover_query_string));

  mysql_mutex_lock(&LOCK_gdl);
  for (i= 1; i <= global_ddl_log.num_entries; i++)
  {
    if (read_ddl_log_entry(i, &ddl_log_entry))
    {
      error= -1;
      continue;
    }
    if (ddl_log_entry.entry_type == DDL_LOG_EXECUTE_CODE)
    {
      /*
        Remeber information about executive ddl log entry,
        used for binary logging during recovery
      */
      recovery_state.execute_entry_pos= i;
      recovery_state.xid= ddl_log_entry.xid;

      /* purecov: begin tested */
      if ((ddl_log_entry.unique_id & DDL_LOG_RETRY_MASK) > DDL_LOG_MAX_RETRY)
      {
        error= -1;
        continue;
      }
      update_unique_id(i, ++ddl_log_entry.unique_id);
      if ((ddl_log_entry.unique_id & DDL_LOG_RETRY_MASK) > DDL_LOG_MAX_RETRY)
      {
        sql_print_error("DDL_LOG: Aborting executing entry %u after %llu "
                        "retries", i, ddl_log_entry.unique_id);
        error= -1;
        continue;
      }
      /* purecov: end tested */

      uint cond_entry= (uint)(ddl_log_entry.unique_id >> DDL_LOG_RETRY_BITS);

      if (cond_entry && is_execute_entry_active(cond_entry))
      {
        if (disable_execute_entry(i))
          error= -1;
        continue;
      }

      if (ddl_log_execute_entry_no_lock(thd, ddl_log_entry.next_entry))
      {
        /* Real unpleasant scenario but we have to continue anyway  */
        error= -1;
        continue;
      }
      count++;
    }
  }
  recovery_state.drop_table.free();
  recovery_state.drop_view.free();
  recovery_state.query.free();
  recovery_state.db.free();
  close_ddl_log();
  mysql_mutex_unlock(&LOCK_gdl);
  thd->reset_query();
  delete thd;
  set_current_thd(original_thd);

  /*
    Create a new ddl_log to get rid of old stuff and ensure that header matches
    the current source version
   */
  if (create_ddl_log())
    error= 1;
  if (count > 0)
    sql_print_information("DDL_LOG: Crash recovery executed %u entries",
                          count);

  set_current_thd(original_thd);
  DBUG_RETURN(error);
}


static void ddl_log_free_lists()
{
  DDL_LOG_MEMORY_ENTRY *free_list= global_ddl_log.first_free;
  DDL_LOG_MEMORY_ENTRY *used_list= global_ddl_log.first_used;

  while (used_list)
  {
    DDL_LOG_MEMORY_ENTRY *tmp= used_list->next_log_entry;
    my_free(used_list);
    used_list= tmp;
  }
  while (free_list)
  {
    DDL_LOG_MEMORY_ENTRY *tmp= free_list->next_log_entry;
    my_free(free_list);
    free_list= tmp;
  }
  global_ddl_log.first_free= global_ddl_log.first_used= 0;
}


/**
  Release all memory allocated to the ddl log and delete the ddl log
*/

void ddl_log_release()
{
  char file_name[FN_REFLEN];
  DBUG_ENTER("ddl_log_release");

  if (!global_ddl_log.initialized)
    DBUG_VOID_RETURN;

  global_ddl_log.initialized= 0;
  ddl_log_free_lists();

  my_free(global_ddl_log.file_entry_buf);
  global_ddl_log.file_entry_buf= 0;
  close_ddl_log();

  create_ddl_log_file_name(file_name, 0);
  (void) mysql_file_delete(key_file_global_ddl_log, file_name, MYF(0));
  mysql_mutex_destroy(&LOCK_gdl);
  DBUG_VOID_RETURN;
}


/**
   Methods for DDL_LOG_STATE
*/

void ddl_log_add_entry(DDL_LOG_STATE *state, DDL_LOG_MEMORY_ENTRY *log_entry)
{
  log_entry->next_active_log_entry= state->list;
  state->main_entry= state->list= log_entry;
}


void ddl_log_release_entries(DDL_LOG_STATE *ddl_log_state)
{
  DDL_LOG_MEMORY_ENTRY *next;
  for (DDL_LOG_MEMORY_ENTRY *log_entry= ddl_log_state->list;
       log_entry;
       log_entry= next)
  {
    next= log_entry->next_active_log_entry;
    ddl_log_release_memory_entry(log_entry);
  }
  ddl_log_state->list= 0;

  if (ddl_log_state->execute_entry)
  {
    ddl_log_release_memory_entry(ddl_log_state->execute_entry);
    ddl_log_state->execute_entry= 0;            // Not needed but future safe
  }
}


/****************************************************************************
   Implementations of common ddl entries
*****************************************************************************/

/**
   Complete ddl logging.  This is done when all statements has completed
   successfully and we can disable the execute log entry.
*/

void ddl_log_complete(DDL_LOG_STATE *state)
{
  DBUG_ENTER("ddl_log_complete");

  if (unlikely(!state->list))
    DBUG_VOID_RETURN;                           // ddl log not used

  mysql_mutex_lock(&LOCK_gdl);
  if (likely(state->execute_entry))
    ddl_log_disable_execute_entry(&state->execute_entry);
  ddl_log_release_entries(state);
  mysql_mutex_unlock(&LOCK_gdl);
  state->list= 0;
  DBUG_VOID_RETURN;
};


/**
  Revert (execute) all entries in the ddl log

  This is called for failed rename table, create trigger or drop trigger.
*/

bool ddl_log_revert(THD *thd, DDL_LOG_STATE *state)
{
  bool res= 0;
  DBUG_ENTER("ddl_log_revert");

  if (unlikely(!state->list))
    DBUG_RETURN(0);                             // ddl log not used

  mysql_mutex_lock(&LOCK_gdl);
  if (likely(state->execute_entry))
  {
    res= ddl_log_execute_entry_no_lock(thd, state->list->entry_pos);
    ddl_log_disable_execute_entry(&state->execute_entry);
  }
  ddl_log_release_entries(state);
  mysql_mutex_unlock(&LOCK_gdl);
  state->list= 0;
  DBUG_RETURN(res);
}


/*
  Update phase of main ddl log entry (usually the last one created,
  except in case of query events, the one before the query event).
*/

bool ddl_log_update_phase(DDL_LOG_STATE *state, uchar phase)
{
  DBUG_ENTER("ddl_log_update_phase");
  if (likely(state->list))
    DBUG_RETURN(update_phase(state->main_entry->entry_pos, phase));
  DBUG_RETURN(0);
}


/*
  Update flag bits in main ddl log entry (usually last created, except in case
  of query events, the one before the query event.
*/

bool ddl_log_add_flag(DDL_LOG_STATE *state, uint16 flags)
{
  DBUG_ENTER("ddl_log_update_phase");
  if (likely(state->list))
  {
    state->flags|= flags;
    DBUG_RETURN(update_flags(state->main_entry->entry_pos, state->flags));
  }
  DBUG_RETURN(0);
}


/**
   Update unique_id (used for inplace alter table)
*/

bool ddl_log_update_unique_id(DDL_LOG_STATE *state, ulonglong id)
{
  DBUG_ENTER("ddl_log_update_unique_id");
  DBUG_PRINT("enter", ("id: %llu", id));
  /* The following may not be true in case of temporary tables */
  if (likely(state->list))
    DBUG_RETURN(update_unique_id(state->main_entry->entry_pos, id));
  DBUG_RETURN(0);
}


/**
   Disable last ddl entry
*/

bool ddl_log_disable_entry(DDL_LOG_STATE *state)
{
  DBUG_ENTER("ddl_log_disable_entry");
  /* The following may not be true in case of temporary tables */
  if (likely(state->list))
    DBUG_RETURN(update_phase(state->list->entry_pos, DDL_LOG_FINAL_PHASE));
  DBUG_RETURN(0);
}


/**
   Update XID for execute event
*/

bool ddl_log_update_xid(DDL_LOG_STATE *state, ulonglong xid)
{
  DBUG_ENTER("ddl_log_update_xid");
  DBUG_PRINT("enter", ("xid: %llu", xid));
  /* The following may not be true in case of temporary tables */
  if (likely(state->execute_entry))
    DBUG_RETURN(update_xid(state->execute_entry->entry_pos, xid));
  DBUG_RETURN(0);
}


/*
  Write ddl_log_entry and write or update ddl_execute_entry

  Will update DDL_LOG_STATE->flags
*/

static bool ddl_log_write(DDL_LOG_STATE *ddl_state,
                          DDL_LOG_ENTRY *ddl_log_entry)
{
  int error;
  DDL_LOG_MEMORY_ENTRY *log_entry;
  DBUG_ENTER("ddl_log_write");

  mysql_mutex_lock(&LOCK_gdl);
  error= ((ddl_log_write_entry(ddl_log_entry, &log_entry)) ||
          ddl_log_write_execute_entry(log_entry->entry_pos, 0,
                                      &ddl_state->execute_entry));
  mysql_mutex_unlock(&LOCK_gdl);
  if (error)
  {
    if (log_entry)
      ddl_log_release_memory_entry(log_entry);
    DBUG_RETURN(1);
  }
  ddl_log_add_entry(ddl_state, log_entry);
  ddl_state->flags|= ddl_log_entry->flags;      // Update cache
  DBUG_RETURN(0);
}


/**
   Logging of rename table
*/

bool ddl_log_rename_table(DDL_LOG_STATE *ddl_state,
                          handlerton *hton,
                          const LEX_CSTRING *org_db,
                          const LEX_CSTRING *org_alias,
                          const LEX_CSTRING *new_db,
                          const LEX_CSTRING *new_alias)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_rename_file");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));

  ddl_log_entry.action_type=  DDL_LOG_RENAME_TABLE_ACTION;
  ddl_log_entry.next_entry=   ddl_state->list ? ddl_state->list->entry_pos : 0;
  lex_string_set(&ddl_log_entry.handler_name,
                 ha_resolve_storage_engine_name(hton));
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(new_db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(new_alias);
  ddl_log_entry.from_db=      *const_cast<LEX_CSTRING*>(org_db);
  ddl_log_entry.from_name=    *const_cast<LEX_CSTRING*>(org_alias);
  ddl_log_entry.phase=        DDL_RENAME_PHASE_TABLE;

  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}

/*
  Logging of rename view
*/

bool ddl_log_rename_view(DDL_LOG_STATE *ddl_state,
                         const LEX_CSTRING *org_db,
                         const LEX_CSTRING *org_alias,
                         const LEX_CSTRING *new_db,
                         const LEX_CSTRING *new_alias)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_rename_file");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));

  ddl_log_entry.action_type=  DDL_LOG_RENAME_VIEW_ACTION;
  ddl_log_entry.next_entry=   ddl_state->list ? ddl_state->list->entry_pos : 0;
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(new_db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(new_alias);
  ddl_log_entry.from_db=      *const_cast<LEX_CSTRING*>(org_db);
  ddl_log_entry.from_name=    *const_cast<LEX_CSTRING*>(org_alias);

  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Logging of DROP TABLE and DROP VIEW

   Note that in contrast to rename, which are re-done in reverse order,
   deletes are stored in a linked list according to delete order. This
   is to ensure that the tables, for the query generated for binlog,
   is in original delete order.
*/

static bool ddl_log_drop_init(DDL_LOG_STATE *ddl_state,
                              ddl_log_action_code action_code,
                              const LEX_CSTRING *db,
                              const LEX_CSTRING *comment)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_drop_file");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));

  ddl_log_entry.action_type=  action_code;
  ddl_log_entry.from_db=      *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(comment);

  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


bool ddl_log_drop_table_init(DDL_LOG_STATE *ddl_state,
                             const LEX_CSTRING *db,
                             const LEX_CSTRING *comment)
{
  return ddl_log_drop_init(ddl_state, DDL_LOG_DROP_INIT_ACTION,
                           db, comment);
}

bool ddl_log_drop_view_init(DDL_LOG_STATE *ddl_state,
                            const LEX_CSTRING *db)
{
  return ddl_log_drop_init(ddl_state, DDL_LOG_DROP_INIT_ACTION,
                           db, &empty_clex_str);
}


/**
   Log DROP TABLE to the ddl log.

   This code does not call ddl_log_write() as we want the events to
   be stored in call order instead of reverse order, which is the normal
   case for all other events.
   See also comment before ddl_log_drop_init().
*/

static bool ddl_log_drop(DDL_LOG_STATE *ddl_state,
                         ddl_log_action_code action_code,
                         uint phase,
                         handlerton *hton,
                         const LEX_CSTRING *path,
                         const LEX_CSTRING *db,
                         const LEX_CSTRING *table)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DDL_LOG_MEMORY_ENTRY *log_entry;
  DBUG_ENTER("ddl_log_drop");

  DBUG_ASSERT(ddl_state->list);
  bzero(&ddl_log_entry, sizeof(ddl_log_entry));

  ddl_log_entry.action_type=  action_code;
  if (hton)
    lex_string_set(&ddl_log_entry.handler_name,
                   ha_resolve_storage_engine_name(hton));
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(table);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(path);
  ddl_log_entry.phase=        (uchar) phase;

  mysql_mutex_lock(&LOCK_gdl);
  if (ddl_log_write_entry(&ddl_log_entry, &log_entry))
    goto error;

  (void) ddl_log_sync_no_lock();
  if (update_next_entry_pos(ddl_state->list->entry_pos,
                            log_entry->entry_pos))
  {
    ddl_log_release_memory_entry(log_entry);
    goto error;
  }

  mysql_mutex_unlock(&LOCK_gdl);
  ddl_log_add_entry(ddl_state, log_entry);
  DBUG_RETURN(0);

error:
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(1);
}


bool ddl_log_drop_table(DDL_LOG_STATE *ddl_state,
                        handlerton *hton,
                        const LEX_CSTRING *path,
                        const LEX_CSTRING *db,
                        const LEX_CSTRING *table)
{
  DBUG_ENTER("ddl_log_drop_table");
  DBUG_RETURN(ddl_log_drop(ddl_state,
                           DDL_LOG_DROP_TABLE_ACTION, DDL_DROP_PHASE_TABLE,
                           hton, path, db, table));
}


bool ddl_log_drop_view(DDL_LOG_STATE *ddl_state,
                        const LEX_CSTRING *path,
                        const LEX_CSTRING *db,
                        const LEX_CSTRING *table)
{
  DBUG_ENTER("ddl_log_drop_view");
  DBUG_RETURN(ddl_log_drop(ddl_state,
                           DDL_LOG_DROP_VIEW_ACTION, 0,
                           (handlerton*) 0, path, db, table));
}


bool ddl_log_drop_trigger(DDL_LOG_STATE *ddl_state,
                          const LEX_CSTRING *db,
                          const LEX_CSTRING *table,
                          const LEX_CSTRING *trigger_name,
                          const LEX_CSTRING *query)
{
  DDL_LOG_ENTRY ddl_log_entry;
  MY_STAT stat_info;
  char path[FN_REFLEN+1];
  off_t frm_length= 0;
  size_t max_query_length;
  DBUG_ENTER("ddl_log_drop_trigger");

  build_table_filename(path, sizeof(path)-1, db->str, table->str, TRG_EXT, 0);

  /* We can use length of frm file as an indication if trigger was removed */
  if (my_stat(path, &stat_info, MYF(MY_WME | ME_WARNING)))
    frm_length= (off_t) stat_info.st_size;

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));

  ddl_log_entry.action_type=  DDL_LOG_DROP_TRIGGER_ACTION;
  ddl_log_entry.unique_id=    (ulonglong) frm_length;
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(table);
  ddl_log_entry.from_name=    *const_cast<LEX_CSTRING*>(trigger_name);

  /*
    If we can store query as is, we store it. Otherwise it will be
    re-generated on recovery
  */

  max_query_length= ddl_log_free_space_in_entry(&ddl_log_entry);
  if (max_query_length >= query->length)
    ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(query);

  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Log DROP DATABASE

   This is logged after all DROP TABLE's for the database.
   As now know we are going to log DROP DATABASE to the binary log, we want
   to ignore want to ignore all preceding DROP TABLE entries. We do that by
   linking this entry directly after the execute entry and forgetting the
   link to the previous entries (not setting ddl_log_entry.next_entry)
*/

bool ddl_log_drop_db(DDL_LOG_STATE *ddl_state,
                     const LEX_CSTRING *db, const LEX_CSTRING *path)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_drop_db");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_DROP_DB_ACTION;
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(path);
  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Log CREATE TABLE

   @param only_frm  On recovery, only drop the .frm. This is needed for
                    example when deleting a table that was discovered.
*/

bool ddl_log_create_table(DDL_LOG_STATE *ddl_state,
                          handlerton *hton,
                          const LEX_CSTRING *path,
                          const LEX_CSTRING *db,
                          const LEX_CSTRING *table,
                          bool only_frm)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_create_table");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type= DDL_LOG_CREATE_TABLE_ACTION;
  if (hton)
    lex_string_set(&ddl_log_entry.handler_name,
                   ha_resolve_storage_engine_name(hton));
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(table);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(path);
  ddl_log_entry.flags=        only_frm ? DDL_LOG_FLAG_ONLY_FRM : 0;

  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Log CREATE VIEW
*/

bool ddl_log_create_view(DDL_LOG_STATE *ddl_state,
                         const LEX_CSTRING *path,
                         enum_ddl_log_create_view_phase phase)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_create_view");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_CREATE_VIEW_ACTION;
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(path);
  ddl_log_entry.phase=        (uchar) phase;
  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
  Log creation of temporary file that should be deleted during recovery

  @param ddl_log_state   ddl_state
  @param path            Path to file to be deleted
  @param depending_state If not NULL, then do not delete the temp file if this
                         entry exists and is active.
*/

bool ddl_log_delete_tmp_file(DDL_LOG_STATE *ddl_state,
                             const LEX_CSTRING *path,
                             DDL_LOG_STATE *depending_state)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_delete_tmp_file");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_DELETE_TMP_FILE_ACTION;
  ddl_log_entry.next_entry=   ddl_state->list ? ddl_state->list->entry_pos : 0;
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(path);
  if (depending_state)
    ddl_log_entry.unique_id= depending_state->execute_entry->entry_pos;
  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Log CREATE TRIGGER
*/

bool ddl_log_create_trigger(DDL_LOG_STATE *ddl_state,
                            const LEX_CSTRING *db, const LEX_CSTRING *table,
                            const LEX_CSTRING *trigger_name,
                            enum_ddl_log_create_trigger_phase phase)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_create_view");

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_CREATE_TRIGGER_ACTION;
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(table);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(trigger_name);
  ddl_log_entry.phase=        (uchar) phase;
  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/**
   Log ALTER TABLE

   $param backup_name   Name of backup table. In case of ALTER TABLE rename
                        this is the final table name
*/

bool ddl_log_alter_table(DDL_LOG_STATE *ddl_state,
                         handlerton *org_hton,
                         const LEX_CSTRING *db, const LEX_CSTRING *table,
                         handlerton *new_hton,
                         handlerton *partition_underlying_hton,
                         const LEX_CSTRING *new_db,
                         const LEX_CSTRING *new_table,
                         const LEX_CSTRING *frm_path,
                         const LEX_CSTRING *backup_name,
                         const LEX_CUSTRING *version,
                         ulonglong table_version,
                         bool is_renamed)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DBUG_ENTER("ddl_log_alter_table");
  DBUG_ASSERT(new_hton);
  DBUG_ASSERT(org_hton);

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_ALTER_TABLE_ACTION;
  if (new_hton)
    lex_string_set(&ddl_log_entry.handler_name,
                   ha_resolve_storage_engine_name(new_hton));
  /* Store temporary table name */
  ddl_log_entry.db=           *const_cast<LEX_CSTRING*>(new_db);
  ddl_log_entry.name=         *const_cast<LEX_CSTRING*>(new_table);
  if (org_hton)
    lex_string_set(&ddl_log_entry.from_handler_name,
                   ha_resolve_storage_engine_name(org_hton));
  ddl_log_entry.from_db=      *const_cast<LEX_CSTRING*>(db);
  ddl_log_entry.from_name=    *const_cast<LEX_CSTRING*>(table);
  ddl_log_entry.tmp_name=     *const_cast<LEX_CSTRING*>(frm_path);
  ddl_log_entry.extra_name=   *const_cast<LEX_CSTRING*>(backup_name);
  ddl_log_entry.flags=        is_renamed ? DDL_LOG_FLAG_ALTER_RENAME : 0;
  ddl_log_entry.unique_id=    table_version;

  /*
    If we are doing an inplace of a partition engine, we need to log the
    underlaying engine. We store this is in ddl_log_entry.handler_name
  */
  if (new_hton == org_hton && partition_underlying_hton != new_hton)
  {
    lex_string_set(&ddl_log_entry.handler_name,
                   ha_resolve_storage_engine_name(partition_underlying_hton));
    ddl_log_entry.flags|= DDL_LOG_FLAG_ALTER_PARTITION;
  }
  DBUG_ASSERT(version->length == MY_UUID_SIZE);
  memcpy(ddl_log_entry.uuid, version->str, version->length);
  DBUG_RETURN(ddl_log_write(ddl_state, &ddl_log_entry));
}


/*
  Store query that later should be logged to binary log

  The links of the query log event is

  execute_log_event -> first log_query_event [-> log_query_event...] ->
  action_log_event (probably a LOG_ALTER_TABLE_ACTION event)

  This ensures that when we execute the log_query_event it can collect
  the full query from the log_query_events and then execute the
  action_log_event with the original query stored in 'recovery_state.query'.

  The query is stored in ddl_log_entry.extra_name as this is the last string
  stored in the log block (makes it easier to check and debug).
*/

bool ddl_log_store_query(THD *thd, DDL_LOG_STATE *ddl_state,
                         const char *query, size_t length)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DDL_LOG_MEMORY_ENTRY *first_entry, *next_entry= 0;
  DDL_LOG_MEMORY_ENTRY *original_entry= ddl_state->list;
  size_t max_query_length;
  uint entry_pos, next_entry_pos= 0, parent_entry_pos;
  DBUG_ENTER("ddl_log_store_query");
  DBUG_ASSERT(length <= UINT_MAX32);
  DBUG_ASSERT(length > 0);
  DBUG_ASSERT(ddl_state->list);

  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type=  DDL_LOG_STORE_QUERY_ACTION;
  ddl_log_entry.unique_id=    length;
  ddl_log_entry.flags=        1;                // First entry
  ddl_log_entry.db= thd->db;                    // Current database

  max_query_length= ddl_log_free_space_in_entry(&ddl_log_entry);

  mysql_mutex_lock(&LOCK_gdl);
  ddl_log_entry.entry_type= DDL_LOG_ENTRY_CODE;

  if (ddl_log_get_free_entry(&first_entry))
    goto err;
  parent_entry_pos= ddl_state->list->entry_pos;
  entry_pos= first_entry->entry_pos;
  ddl_log_add_entry(ddl_state, first_entry);

  while (length)
  {
    size_t write_length= MY_MIN(length, max_query_length);
    ddl_log_entry.extra_name.str= query;
    ddl_log_entry.extra_name.length= write_length;

    query+= write_length;
    length-= write_length;

    if (length > 0)
    {
      if (ddl_log_get_free_entry(&next_entry))
        goto err;
      ddl_log_entry.next_entry= next_entry_pos= next_entry->entry_pos;
      ddl_log_add_entry(ddl_state, next_entry);
    }
    else
    {
      /* point next link of last query_action event to the original action */
      ddl_log_entry.next_entry= parent_entry_pos;
    }
    set_global_from_ddl_log_entry(&ddl_log_entry);
    if (unlikely(write_ddl_log_file_entry(entry_pos)))
      goto err;
    entry_pos= next_entry_pos;
    ddl_log_entry.flags= 0;           // Only first entry has this set
    ddl_log_entry.db.length= 0;       // Don't need DB anymore
    ddl_log_entry.extra_name.length= 0;
    max_query_length= ddl_log_free_space_in_entry(&ddl_log_entry);
  }
  if (ddl_log_write_execute_entry(first_entry->entry_pos,
                                  &ddl_state->execute_entry))
    goto err;

  /* Set the original entry to be used for future PHASE updates */
  ddl_state->main_entry= original_entry;
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(0);
err:
  /*
    Allocated ddl_log entries will be released by the
    ddl_log_release_entries() call in dl_log_complete()
  */
  mysql_mutex_unlock(&LOCK_gdl);
  DBUG_RETURN(1);
}


/*
  Log an delete frm file
*/

/*
  TODO: Partitioning atomic DDL refactoring: this should be replaced with
        ddl_log_create_table().
*/
bool ddl_log_delete_frm(DDL_LOG_STATE *ddl_state, const char *to_path)
{
  DDL_LOG_ENTRY ddl_log_entry;
  DDL_LOG_MEMORY_ENTRY *log_entry;
  DBUG_ENTER("ddl_log_delete_frm");
  bzero(&ddl_log_entry, sizeof(ddl_log_entry));
  ddl_log_entry.action_type= DDL_LOG_DELETE_ACTION;
  ddl_log_entry.next_entry= ddl_state->list ? ddl_state->list->entry_pos : 0;

  lex_string_set(&ddl_log_entry.handler_name, reg_ext);
  lex_string_set(&ddl_log_entry.name, to_path);

  mysql_mutex_assert_owner(&LOCK_gdl);
  if (ddl_log_write_entry(&ddl_log_entry, &log_entry))
    DBUG_RETURN(1);

  ddl_log_add_entry(ddl_state, log_entry);
  DBUG_RETURN(0);
}