~drizzle-trunk/drizzle/development

/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
 *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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 *  Copyright (C) 2008 Sun Microsystems
 *
 *  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  02110-1301  USA
 */

/**
  @addtogroup Replication
  @{

  @file
  
  @brief Binary log event definitions.  This includes generic code
  common to all types of log events, as well as specific code for each
  type of log event.
*/


#ifndef DRIZZLED_LOG_EVENT_H
#define DRIZZLED_LOG_EVENT_H


#include <mysys/my_bitmap.h>
#include <drizzled/replication/constants.h>
#include <drizzled/replication/record.h>
#include <drizzled/replication/reporting.h>
#include <drizzled/session.h>
#include <string>

#include <drizzled/sql_string.h>       /* append_query_string() needs String declaration */

/**
   Either assert or return an error.

   In debug build, the condition will be checked, but in non-debug
   builds, the error code given will be returned instead.

   @param COND   Condition to check
   @param ERRNO  Error number to return in non-debug builds
*/
#define ASSERT_OR_RETURN_ERROR(COND, ERRNO) \
  assert(COND)

#define LOG_READ_EOF    -1
#define LOG_READ_BOGUS  -2
#define LOG_READ_IO     -3
#define LOG_READ_MEM    -5
#define LOG_READ_TRUNC  -6
#define LOG_READ_TOO_LARGE -7

#define LOG_EVENT_OFFSET 4

/*
   3 is MySQL 4.x; 4 is MySQL 5.0.0.
   Compared to version 3, version 4 has:
   - a different Start_log_event, which includes info about the binary log
   (sizes of headers); this info is included for better compatibility if the
   master's MySQL version is different from the slave's.
   - all events have a unique ID (the triplet (server_id, timestamp at server
   start, other) to be sure an event is not executed more than once in a
   multimaster setup, example:
                M1
              /   \
             v     v
             M2    M3
             \     /
              v   v
                S
   if a query is run on M1, it will arrive twice on S, so we need that S
   remembers the last unique ID it has processed, to compare and know if the
   event should be skipped or not. Example of ID: we already have the server id
   (4 bytes), plus:
   timestamp_when_the_master_started (4 bytes), a counter (a sequence number
   which increments every time we write an event to the binlog) (3 bytes).
   Q: how do we handle when the counter is overflowed and restarts from 0 ?

   - Query and Load (Create or Execute) events may have a more precise
     timestamp (with microseconds), number of matched/affected/warnings rows
   and fields of session variables: SQL_MODE,
   FOREIGN_KEY_CHECKS, UNIQUE_CHECKS, SQL_AUTO_IS_NULL, the collations and
   charsets, the PASSWORD() version (old/new/...).
*/
#define BINLOG_VERSION    4

/*
 We could have used SERVER_VERSION_LENGTH, but this introduces an
 obscure dependency - if somebody decided to change SERVER_VERSION_LENGTH
 this would break the replication protocol
*/
#define ST_SERVER_VER_LEN 50

/*
  These are flags and structs to handle all the LOAD DATA INFILE options (LINES
  TERMINATED etc).
*/

/*
  These are flags and structs to handle all the LOAD DATA INFILE options (LINES
  TERMINATED etc).
  DUMPFILE_FLAG is probably useless (DUMPFILE is a clause of SELECT, not of LOAD
  DATA).
*/
#define DUMPFILE_FLAG		0x1
#define OPT_ENCLOSED_FLAG	0x2
#define REPLACE_FLAG		0x4
#define IGNORE_FLAG		0x8

#define FIELD_TERM_EMPTY	0x1
#define ENCLOSED_EMPTY		0x2
#define LINE_TERM_EMPTY		0x4
#define LINE_START_EMPTY	0x8
#define ESCAPED_EMPTY		0x10

#define NUM_LOAD_DELIM_STRS 5

/*****************************************************************************

  sql_ex_info struct

 ****************************************************************************/
struct sql_ex_info
{
  sql_ex_info() {}                            /* Remove gcc warning */
  const char* field_term;
  const char* enclosed;
  const char* line_term;
  const char* line_start;
  const char* escaped;
  int cached_new_format;
  uint8_t field_term_len,enclosed_len,line_term_len,line_start_len, escaped_len;
  char opt_flags;
  char empty_flags;

  /* store in new format even if old is possible */
  void force_new_format() { cached_new_format = 1;}
  int data_size()
  {
    return (new_format() ?
	    field_term_len + enclosed_len + line_term_len +
	    line_start_len + escaped_len + 6 : 7);
  }
  bool write_data(IO_CACHE* file);
  const char* init(const char* buf, const char* buf_end, bool use_new_format);
  bool new_format()
  {
    return ((cached_new_format != -1) ? cached_new_format :
	    (cached_new_format=(field_term_len > 1 ||
				enclosed_len > 1 ||
				line_term_len > 1 || line_start_len > 1 ||
				escaped_len > 1)));
  }
};

/*****************************************************************************

  MySQL Binary Log

  This log consists of events.  Each event has a fixed-length header,
  possibly followed by a variable length data body.

  The data body consists of an optional fixed length segment (post-header)
  and  an optional variable length segment.

  See the #defines below for the format specifics.

  The events which really update data are Query_log_event,
  Execute_load_query_log_event and old Load_log_event and
  Execute_load_log_event events (Execute_load_query is used together with
  Begin_load_query and Append_block events to replicate LOAD DATA INFILE.
  Create_file/Append_block/Execute_load (which includes Load_log_event)
  were used to replicate LOAD DATA before the 5.0.3).

 ****************************************************************************/

#define LOG_EVENT_HEADER_LEN 19     /* the fixed header length */
#define OLD_HEADER_LEN       13     /* the fixed header length in 3.23 */
/*
   Fixed header length, where 4.x and 5.0 agree. That is, 5.0 may have a longer
   header (it will for sure when we have the unique event's ID), but at least
   the first 19 bytes are the same in 4.x and 5.0. So when we have the unique
   event's ID, LOG_EVENT_HEADER_LEN will be something like 26, but
   LOG_EVENT_MINIMAL_HEADER_LEN will remain 19.
*/
#define LOG_EVENT_MINIMAL_HEADER_LEN (uint8_t)19

/* event-specific post-header sizes */
// where 3.23, 4.x and 5.0 agree
#define QUERY_HEADER_MINIMAL_LEN     (4 + 4 + 1 + 2)
// where 5.0 differs: 2 for len of N-bytes vars.
#define QUERY_HEADER_LEN     (QUERY_HEADER_MINIMAL_LEN + 2)
#define LOAD_HEADER_LEN      (4 + 4 + 4 + 1 +1 + 4)
#define START_V3_HEADER_LEN     (2 + ST_SERVER_VER_LEN + 4)
#define ROTATE_HEADER_LEN    8 // this is FROZEN (the Rotate post-header is frozen)
#define CREATE_FILE_HEADER_LEN 4
#define APPEND_BLOCK_HEADER_LEN 4
#define EXEC_LOAD_HEADER_LEN   4
#define DELETE_FILE_HEADER_LEN 4
#define FORMAT_DESCRIPTION_HEADER_LEN (START_V3_HEADER_LEN+1+LOG_EVENT_TYPES)
#define ROWS_HEADER_LEN        8
#define TABLE_MAP_HEADER_LEN   8
#define EXECUTE_LOAD_QUERY_EXTRA_HEADER_LEN (4 + 4 + 4 + 1)
#define EXECUTE_LOAD_QUERY_HEADER_LEN  (QUERY_HEADER_LEN + EXECUTE_LOAD_QUERY_EXTRA_HEADER_LEN)
#define INCIDENT_HEADER_LEN    2
#define HEARTBEAT_HEADER_LEN   0
/* 
  Max number of possible extra bytes in a replication event compared to a
  packet (i.e. a query) sent from client to master;
  First, an auxiliary log_event status vars estimation:
*/
#define MAX_SIZE_LOG_EVENT_STATUS (4 /* flags2 */   + \
                                   8 /* sql mode */ + \
                                   1 + 1 + 255 /* catalog */ + \
                                   4 /* autoinc */ + \
                                   6 /* charset */ + \
                                   MAX_TIME_ZONE_NAME_LENGTH)
#define MAX_LOG_EVENT_HEADER   ( /* in order of Query_log_event::write */ \
  LOG_EVENT_HEADER_LEN + /* write_header */ \
  QUERY_HEADER_LEN     + /* write_data */   \
  EXECUTE_LOAD_QUERY_EXTRA_HEADER_LEN + /*write_post_header_for_derived */ \
  MAX_SIZE_LOG_EVENT_STATUS + /* status */ \
  NAME_LEN + 1)

/* 
   Event header offsets; 
   these point to places inside the fixed header.
*/

#define EVENT_TYPE_OFFSET    4
#define SERVER_ID_OFFSET     5
#define EVENT_LEN_OFFSET     9
#define LOG_POS_OFFSET       13
#define FLAGS_OFFSET         17

/* start event post-header (for v3 and v4) */

#define ST_BINLOG_VER_OFFSET  0
#define ST_SERVER_VER_OFFSET  2
#define ST_CREATED_OFFSET     (ST_SERVER_VER_OFFSET + ST_SERVER_VER_LEN)
#define ST_COMMON_HEADER_LEN_OFFSET (ST_CREATED_OFFSET + 4)

/* slave event post-header (this event is never written) */

#define SL_MASTER_PORT_OFFSET   8
#define SL_MASTER_POS_OFFSET    0
#define SL_MASTER_HOST_OFFSET   10

/* query event post-header */

#define Q_THREAD_ID_OFFSET	0
#define Q_EXEC_TIME_OFFSET	4
#define Q_DB_LEN_OFFSET		8
#define Q_ERR_CODE_OFFSET	9
#define Q_STATUS_VARS_LEN_OFFSET 11
#define Q_DATA_OFFSET		QUERY_HEADER_LEN
/* these are codes, not offsets; not more than 256 values (1 byte). */
#define Q_FLAGS2_CODE           0

#define Q_LC_TIME_NAMES_CODE    7

#define Q_CHARSET_DATABASE_CODE 8
/* Intvar event post-header */

#define I_TYPE_OFFSET        0
#define I_VAL_OFFSET         1

/* Rand event post-header */

#define RAND_SEED1_OFFSET 0
#define RAND_SEED2_OFFSET 8

/* User_var event post-header */

#define UV_VAL_LEN_SIZE        4
#define UV_VAL_IS_NULL         1
#define UV_VAL_TYPE_SIZE       1
#define UV_NAME_LEN_SIZE       4
#define UV_CHARSET_NUMBER_SIZE 4

/* Load event post-header */

#define L_THREAD_ID_OFFSET   0
#define L_EXEC_TIME_OFFSET   4
#define L_SKIP_LINES_OFFSET  8
#define L_TBL_LEN_OFFSET     12
#define L_DB_LEN_OFFSET      13
#define L_NUM_FIELDS_OFFSET  14
#define L_SQL_EX_OFFSET      18
#define L_DATA_OFFSET        LOAD_HEADER_LEN

/* Rotate event post-header */

#define R_POS_OFFSET       0
#define R_IDENT_OFFSET     8

/* CF to DF handle LOAD DATA INFILE */

/* CF = "Create File" */
#define CF_FILE_ID_OFFSET  0
#define CF_DATA_OFFSET     CREATE_FILE_HEADER_LEN

/* AB = "Append Block" */
#define AB_FILE_ID_OFFSET  0
#define AB_DATA_OFFSET     APPEND_BLOCK_HEADER_LEN

/* EL = "Execute Load" */
#define EL_FILE_ID_OFFSET  0

/* DF = "Delete File" */
#define DF_FILE_ID_OFFSET  0

/* TM = "Table Map" */
#define TM_MAPID_OFFSET    0
#define TM_FLAGS_OFFSET    6

/* RW = "RoWs" */
#define RW_MAPID_OFFSET    0
#define RW_FLAGS_OFFSET    6

/* ELQ = "Execute Load Query" */
#define ELQ_FILE_ID_OFFSET QUERY_HEADER_LEN
#define ELQ_FN_POS_START_OFFSET ELQ_FILE_ID_OFFSET + 4
#define ELQ_FN_POS_END_OFFSET ELQ_FILE_ID_OFFSET + 8
#define ELQ_DUP_HANDLING_OFFSET ELQ_FILE_ID_OFFSET + 12

/* 4 bytes which all binlogs should begin with */
#define BINLOG_MAGIC        "\xfe\x62\x69\x6e"

/*
   This flag only makes sense for Format_description_log_event. It is set
   when the event is written, and *reset* when a binlog file is
   closed (yes, it's the only case when MySQL modifies already written
   part of binlog).  Thus it is a reliable indicator that binlog was
   closed correctly.  (Stop_log_event is not enough, there's always a
   small chance that mysqld crashes in the middle of insert and end of
   the binlog would look like a Stop_log_event).

   This flag is used to detect a restart after a crash, and to provide
   "unbreakable" binlog. The problem is that on a crash storage engines
   rollback automatically, while binlog does not.  To solve this we use this
   flag and automatically append ROLLBACK to every non-closed binlog (append
   virtually, on reading, file itself is not changed). If this flag is found,
   mysqlbinlog simply prints "ROLLBACK" Replication master does not abort on
   binlog corruption, but takes it as EOF, and replication slave forces a
   rollback in this case.

   Note, that old binlogs does not have this flag set, so we get a
   a backward-compatible behaviour.
*/

#define LOG_EVENT_BINLOG_IN_USE_F       0x1

/**
  @def LOG_EVENT_THREAD_SPECIFIC_F

  If the query depends on the thread (for example: TEMPORARY Table).
  Currently this is used by mysqlbinlog to know it must print
  SET @@PSEUDO_THREAD_ID=xx; before the query (it would not hurt to print it
  for every query but this would be slow).
*/
#define LOG_EVENT_THREAD_SPECIFIC_F 0x4

/**
  @def LOG_EVENT_SUPPRESS_USE_F

  Suppress the generation of 'USE' statements before the actual
  statement. This flag should be set for any events that does not need
  the current database set to function correctly. Most notable cases
  are 'CREATE DATABASE' and 'DROP DATABASE'.

  This flags should only be used in exceptional circumstances, since
  it introduce a significant change in behaviour regarding the
  replication logic together with the flags --binlog-do-db and
  --replicated-do-db.
 */
#define LOG_EVENT_SUPPRESS_USE_F    0x8

/*
  The table map version internal to the log should be increased after
  the event has been written to the binary log.
 */
#define LOG_EVENT_UPDATE_TABLE_MAP_VERSION_F 0x10

/**
  @def OPTIONS_WRITTEN_TO_BIN_LOG

  OPTIONS_WRITTEN_TO_BIN_LOG are the bits of session->options which must
  be written to the binlog. OPTIONS_WRITTEN_TO_BIN_LOG could be
  written into the Format_description_log_event, so that if later we
  don't want to replicate a variable we did replicate, or the
  contrary, it's doable. But it should not be too hard to decide once
  for all of what we replicate and what we don't, among the fixed 32
  bits of session->options.

  I (Guilhem) have read through every option's usage, and it looks
  like OPTION_AUTO_IS_NULL and OPTION_NO_FOREIGN_KEYS are the only
  ones which alter how the query modifies the table. It's good to
  replicate OPTION_RELAXED_UNIQUE_CHECKS too because otherwise, the
  slave may insert data slower than the master, in InnoDB.
  OPTION_BIG_SELECTS is not needed (the slave thread runs with
  max_join_size=HA_POS_ERROR) and OPTION_BIG_TABLES is not needed
  either, as the manual says (because a too big in-memory temp table
  is automatically written to disk).
*/
#define OPTIONS_WRITTEN_TO_BIN_LOG \
  (OPTION_AUTO_IS_NULL | OPTION_NO_FOREIGN_KEY_CHECKS |  \
   OPTION_RELAXED_UNIQUE_CHECKS | OPTION_NOT_AUTOCOMMIT)

/* Shouldn't be defined before */
#define EXPECTED_OPTIONS \
  ((1U << 14) | (1U << 26) | (1U << 27) | (1U << 19))

#if OPTIONS_WRITTEN_TO_BIN_LOG != EXPECTED_OPTIONS
#error OPTIONS_WRITTEN_TO_BIN_LOG must NOT change their values!
#endif
#undef EXPECTED_OPTIONS         /* You shouldn't use this one */

/**
  @enum Log_event_type

  Enumeration type for the different types of log events.
*/
enum Log_event_type
{
  /*
    Every time you update this enum (when you add a type), you have to
    fix Format_description_log_event::Format_description_log_event().
  */
  UNKNOWN_EVENT= 0,
  START_EVENT_V3= 1,
  QUERY_EVENT= 2,
  STOP_EVENT= 3,
  ROTATE_EVENT= 4,
  INTVAR_EVENT= 5,
  LOAD_EVENT= 6,
  SLAVE_EVENT= 7,
  CREATE_FILE_EVENT= 8,
  APPEND_BLOCK_EVENT= 9,
  EXEC_LOAD_EVENT= 10,
  DELETE_FILE_EVENT= 11,
  /*
    NEW_LOAD_EVENT is like LOAD_EVENT except that it has a longer
    sql_ex, allowing multibyte TERMINATED BY etc; both types share the
    same class (Load_log_event)
  */
  NEW_LOAD_EVENT= 12,
  RAND_EVENT= 13,
  USER_VAR_EVENT= 14,
  FORMAT_DESCRIPTION_EVENT= 15,
  XID_EVENT= 16,
  BEGIN_LOAD_QUERY_EVENT= 17,
  EXECUTE_LOAD_QUERY_EVENT= 18,

  TABLE_MAP_EVENT = 19,

  /*
    These event numbers are used from 5.1.16 and forward
   */
  WRITE_ROWS_EVENT = 23,
  UPDATE_ROWS_EVENT = 24,
  DELETE_ROWS_EVENT = 25,

  /*
    Something out of the ordinary happened on the master
   */
  INCIDENT_EVENT= 26,

  /*
    Heartbeat event to be send by master at its idle time 
    to ensure master's online status to slave 
  */
  HEARTBEAT_LOG_EVENT= 27,
  
  /*
    Add new events here - right above this comment!
    Existing events (except ENUM_END_EVENT) should never change their numbers
  */

  ENUM_END_EVENT /* end marker */
};

/*
   The number of types we handle in Format_description_log_event (UNKNOWN_EVENT
   is not to be handled, it does not exist in binlogs, it does not have a
   format).
*/
#define LOG_EVENT_TYPES (ENUM_END_EVENT-1)

enum Int_event_type
{
  INVALID_INT_EVENT = 0, LAST_INSERT_ID_EVENT = 1, INSERT_ID_EVENT = 2
};


class String;
class DRIZZLE_BIN_LOG;
class Session;

class Format_description_log_event;
class Relay_log_info;

/**
  the struct aggregates two paramenters that identify an event
  uniquely in scope of communication of a particular master and slave couple.
  I.e there can not be 2 events from the same staying connected master which
  have the same coordinates.
  @note
  Such identifier is not yet unique generally as the event originating master
  is resetable. Also the crashed master can be replaced with some other.
*/
struct event_coordinates
{
  char * file_name; // binlog file name (directories stripped)
  my_off_t  pos;       // event's position in the binlog file
};

/**
  @class Log_event

  This is the abstract base class for binary log events.
  
  @section Log_event_binary_format Binary Format

  Any @c Log_event saved on disk consists of the following three
  components.

  - Common-Header
  - Post-Header
  - Body

  The Common-Header, documented in the table @ref Table_common_header
  "below", always has the same form and length within one version of
  MySQL.  Each event type specifies a format and length of the
  Post-Header.  The length of the Common-Header is the same for all
  events of the same type.  The Body may be of different format and
  length even for different events of the same type.  The binary
  formats of Post-Header and Body are documented separately in each
  subclass.  The binary format of Common-Header is as follows.

  <table>
  <caption>Common-Header</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>timestamp</td>
    <td>4 byte unsigned integer</td>
    <td>The time when the query started, in seconds since 1970.
    </td>
  </tr>

  <tr>
    <td>type</td>
    <td>1 byte enumeration</td>
    <td>See enum #Log_event_type.</td>
  </tr>

  <tr>
    <td>server_id</td>
    <td>4 byte unsigned integer</td>
    <td>Server ID of the server that created the event.</td>
  </tr>

  <tr>
    <td>total_size</td>
    <td>4 byte unsigned integer</td>
    <td>The total size of this event, in bytes.  In other words, this
    is the sum of the sizes of Common-Header, Post-Header, and Body.
    </td>
  </tr>

  <tr>
    <td>master_position</td>
    <td>4 byte unsigned integer</td>
    <td>The position of the next event in the master binary log, in
    bytes from the beginning of the file.  In a binlog that is not a
    relay log, this is just the position of the next event, in bytes
    from the beginning of the file.  In a relay log, this is
    the position of the next event in the master's binlog.
    </td>
  </tr>

  <tr>
    <td>flags</td>
    <td>2 byte bitfield</td>
    <td>See Log_event::flags.</td>
  </tr>
  </table>

  Summing up the numbers above, we see that the total size of the
  common header is 19 bytes.

  @subsection Log_event_format_of_atomic_primitives Format of Atomic Primitives

  - All numbers, whether they are 16-, 24-, 32-, or 64-bit numbers,
  are stored in little endian, i.e., the least significant byte first,
  unless otherwise specified.

  @anchor packed_integer
  - Some events use a special format for efficient representation of
  unsigned integers, called Packed Integer.  A Packed Integer has the
  capacity of storing up to 8-byte integers, while small integers
  still can use 1, 3, or 4 bytes.  The value of the first byte
  determines how to read the number, according to the following table:

  <table>
  <caption>Format of Packed Integer</caption>

  <tr>
    <th>First byte</th>
    <th>Format</th>
  </tr>

  <tr>
    <td>0-250</td>
    <td>The first byte is the number (in the range 0-250), and no more
    bytes are used.</td>
  </tr>

  <tr>
    <td>252</td>
    <td>Two more bytes are used.  The number is in the range
    251-0xffff.</td>
  </tr>

  <tr>
    <td>253</td>
    <td>Three more bytes are used.  The number is in the range
    0xffff-0xffffff.</td>
  </tr>

  <tr>
    <td>254</td>
    <td>Eight more bytes are used.  The number is in the range
    0xffffff-0xffffffffffffffff.</td>
  </tr>

  </table>

  - Strings are stored in various formats.  The format of each string
  is documented separately.
*/
class Log_event
{
public:
  /**
     Enumeration of what kinds of skipping (and non-skipping) that can
     occur when the slave executes an event.

     @see shall_skip
     @see do_shall_skip
   */
  enum enum_skip_reason {
    /**
       Don't skip event.
    */
    EVENT_SKIP_NOT,

    /**
       Skip event by ignoring it.

       This means that the slave skip counter will not be changed.
    */
    EVENT_SKIP_IGNORE,

    /**
       Skip event and decrease skip counter.
    */
    EVENT_SKIP_COUNT
  };


  /*
    The following type definition is to be used whenever data is placed 
    and manipulated in a common buffer. Use this typedef for buffers
    that contain data containing binary and character data.
  */
  typedef unsigned char Byte;

  /*
    The offset in the log where this event originally appeared (it is
    preserved in relay logs, making SHOW SLAVE STATUS able to print
    coordinates of the event in the master's binlog). Note: when a
    transaction is written by the master to its binlog (wrapped in
    BEGIN/COMMIT) the log_pos of all the queries it contains is the
    one of the BEGIN (this way, when one does SHOW SLAVE STATUS it
    sees the offset of the BEGIN, which is logical as rollback may
    occur), except the COMMIT query which has its real offset.
  */
  off_t log_pos;
  /*
     A temp buffer for read_log_event; it is later analysed according to the
     event's type, and its content is distributed in the event-specific fields.
  */
  char *temp_buf;
  /*
    Timestamp on the master(for debugging and replication of
    NOW()/TIMESTAMP).  It is important for queries and LOAD DATA
    INFILE. This is set at the event's creation time, except for Query
    and Load (et al.) events where this is set at the query's
    execution time, which guarantees good replication (otherwise, we
    could have a query and its event with different timestamps).
  */
  time_t when;
  /* The number of seconds the query took to run on the master. */
  ulong exec_time;
  /* Number of bytes written by write() function */
  ulong data_written;

  /*
    The master's server id (is preserved in the relay log; used to
    prevent from infinite loops in circular replication).
  */
  uint32_t server_id;

  /**
    Some 16 flags. See the definitions above for LOG_EVENT_TIME_F,
    LOG_EVENT_FORCED_ROTATE_F, LOG_EVENT_THREAD_SPECIFIC_F, and
    LOG_EVENT_SUPPRESS_USE_F for notes.
  */
  uint16_t flags;

  bool cache_stmt;

  /**
    A storage to cache the global system variable's value.
    Handling of a separate event will be governed its member.
  */
  ulong slave_exec_mode;

  Session* session;

  Log_event();
  Log_event(Session* session_arg, uint16_t flags_arg, bool cache_stmt);
  /*
    read_log_event() functions read an event from a binlog or relay
    log; used by SHOW BINLOG EVENTS, the binlog_dump thread on the
    master (reads master's binlog), the slave IO thread (reads the
    event sent by binlog_dump), the slave SQL thread (reads the event
    from the relay log).  If mutex is 0, the read will proceed without
    mutex.  We need the description_event to be able to parse the
    event (to know the post-header's size); in fact in read_log_event
    we detect the event's type, then call the specific event's
    constructor and pass description_event as an argument.
  */
  static Log_event* read_log_event(IO_CACHE* file,
                                   pthread_mutex_t* log_lock,
                                   const Format_description_log_event
                                   *description_event);
  static int read_log_event(IO_CACHE* file, String* packet,
                            pthread_mutex_t* log_lock);
  /*
    init_show_field_list() prepares the column names and types for the
    output of SHOW BINLOG EVENTS; it is used only by SHOW BINLOG
    EVENTS.
  */
  static void init_show_field_list(List<Item>* field_list);
  int net_send(Protocol *protocol, const char* log_name, my_off_t pos);

  /*
    pack_info() is used by SHOW BINLOG EVENTS; as print() it prepares and sends
    a string to display to the user, so it resembles print().
  */

  virtual void pack_info(Protocol *protocol);

  virtual const char* get_db();

  static void *operator new(size_t size)
  {
    return (void*) my_malloc((uint)size, MYF(MY_WME|MY_FAE));
  }

  static void operator delete(void *ptr,
                              size_t)
  {
    free((unsigned char*) ptr);
  }

  /* Placement version of the above operators */
  static void *operator new(size_t, void* ptr) { return ptr; }
  static void operator delete(void*, void*) { }

  bool write_header(IO_CACHE* file, ulong data_length);
  virtual bool write(IO_CACHE* file)
  {
    return (write_header(file, get_data_size()) ||
            write_data_header(file) ||
            write_data_body(file));
  }
  virtual bool write_data_header(IO_CACHE*)
  { return 0; }
  virtual bool write_data_body(IO_CACHE*)
  { return 0; }
  time_t get_time();
  virtual Log_event_type get_type_code() = 0;
  virtual bool is_valid() const = 0;
  virtual bool is_artificial_event() { return 0; }
  inline bool get_cache_stmt() const { return cache_stmt; }
  Log_event(const char* buf, const Format_description_log_event
            *description_event);
  virtual ~Log_event() { free_temp_buf();}
  void register_temp_buf(char* buf) { temp_buf = buf; }
  void free_temp_buf()
  {
    if (temp_buf)
    {
      free(temp_buf);
      temp_buf = 0;
    }
  }
  /*
    Get event length for simple events. For complicated events the length
    is calculated during write()
  */
  virtual int get_data_size() { return 0;}
  static Log_event* read_log_event(const char* buf, uint32_t event_len,
				   const char **error,
                                   const Format_description_log_event
                                   *description_event);
  /**
    Returns the human readable name of the given event type.
  */
  static const char* get_type_str(Log_event_type type);
  /**
    Returns the human readable name of this event's type.
  */
  const char* get_type_str();

  /* Return start of query time or current time */

public:

  /**
     Apply the event to the database.

     This function represents the public interface for applying an
     event.

     @see do_apply_event
   */
  int apply_event(Relay_log_info const *rli)
  {
    return do_apply_event(rli);
  }


  /**
     Update the relay log position.

     This function represents the public interface for "stepping over"
     the event and will update the relay log information.

     @see do_update_pos
   */
  int update_pos(Relay_log_info *rli)
  {
    return do_update_pos(rli);
  }

  /**
     Decide if the event shall be skipped, and the reason for skipping
     it.

     @see do_shall_skip
   */
  enum_skip_reason shall_skip(Relay_log_info *rli)
  {
    return do_shall_skip(rli);
  }

protected:

  /**
     Helper function to ignore an event w.r.t. the slave skip counter.

     This function can be used inside do_shall_skip() for functions
     that cannot end a group. If the slave skip counter is 1 when
     seeing such an event, the event shall be ignored, the counter
     left intact, and processing continue with the next event.

     A typical usage is:
     @code
     enum_skip_reason do_shall_skip(Relay_log_info *rli) {
       return continue_group(rli);
     }
     @endcode

     @return Skip reason
   */
  enum_skip_reason continue_group(Relay_log_info *rli);

  /**
    Primitive to apply an event to the database.

    This is where the change to the database is made.

    @note The primitive is protected instead of private, since there
    is a hierarchy of actions to be performed in some cases.

    @see Format_description_log_event::do_apply_event()

    @param rli Pointer to relay log info structure

    @retval 0     Event applied successfully
    @retval errno Error code if event application failed
  */
  virtual int do_apply_event(Relay_log_info const *)
  {
    return 0;                /* Default implementation does nothing */
  }


  /**
     Advance relay log coordinates.

     This function is called to advance the relay log coordinates to
     just after the event.  It is essential that both the relay log
     coordinate and the group log position is updated correctly, since
     this function is used also for skipping events.

     Normally, each implementation of do_update_pos() shall:

     - Update the event position to refer to the position just after
       the event.

     - Update the group log position to refer to the position just
       after the event <em>if the event is last in a group</em>

     @param rli Pointer to relay log info structure

     @retval 0     Coordinates changed successfully
     @retval errno Error code if advancing failed (usually just
                   1). Observe that handler errors are returned by the
                   do_apply_event() function, and not by this one.
   */
  virtual int do_update_pos(Relay_log_info *rli);


  /**
     Decide if this event shall be skipped or not and the reason for
     skipping it.

     The default implementation decide that the event shall be skipped
     if either:

     - the server id of the event is the same as the server id of the
       server and <code>rli->replicate_same_server_id</code> is true,
       or

     - if <code>rli->slave_skip_counter</code> is greater than zero.

     @see do_apply_event
     @see do_update_pos

     @retval Log_event::EVENT_SKIP_NOT
     The event shall not be skipped and should be applied.

     @retval Log_event::EVENT_SKIP_IGNORE
     The event shall be skipped by just ignoring it, i.e., the slave
     skip counter shall not be changed. This happends if, for example,
     the originating server id of the event is the same as the server
     id of the slave.

     @retval Log_event::EVENT_SKIP_COUNT
     The event shall be skipped because the slave skip counter was
     non-zero. The caller shall decrease the counter by one.
   */
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);
};


/*
   One class for each type of event.
   Two constructors for each class:
   - one to create the event for logging (when the server acts as a master),
   called after an update to the database is done,
   which accepts parameters like the query, the database, the options for LOAD
   DATA INFILE...
   - one to create the event from a packet (when the server acts as a slave),
   called before reproducing the update, which accepts parameters (like a
   buffer). Used to read from the master, from the relay log, and in
   mysqlbinlog. This constructor must be format-tolerant.
*/

/**
  @class Query_log_event
   
  A @c Query_log_event is created for each query that modifies the
  database, unless the query is logged row-based.

  @section Query_log_event_binary_format Binary format

  See @ref Log_event_binary_format "Binary format for log events" for
  a general discussion and introduction to the binary format of binlog
  events.

  The Post-Header has five components:

  <table>
  <caption>Post-Header for Query_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>slave_proxy_id</td>
    <td>4 byte unsigned integer</td>
    <td>An integer identifying the client thread that issued the
    query.  The id is unique per server.  (Note, however, that two
    threads on different servers may have the same slave_proxy_id.)
    This is used when a client thread creates a temporary table local
    to the client.  The slave_proxy_id is used to distinguish
    temporary tables that belong to different clients.
    </td>
  </tr>

  <tr>
    <td>exec_time</td>
    <td>4 byte unsigned integer</td>
    <td>The time from when the query started to when it was logged in
    the binlog, in seconds.</td>
  </tr>

  <tr>
    <td>db_len</td>
    <td>1 byte integer</td>
    <td>The length of the name of the currently selected database.</td>
  </tr>

  <tr>
    <td>error_code</td>
    <td>2 byte unsigned integer</td>
    <td>Error code generated by the master.  If the master fails, the
    slave will fail with the same error code, except for the error
    codes ER_DB_CREATE_EXISTS == 1007 and ER_DB_DROP_EXISTS == 1008.
    </td>
  </tr>

  <tr>
    <td>status_vars_len</td>
    <td>2 byte unsigned integer</td>
    <td>The length of the status_vars block of the Body, in bytes. See
    @ref query_log_event_status_vars "below".
    </td>
  </tr>
  </table>

  The Body has the following components:

  <table>
  <caption>Body for Query_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>@anchor query_log_event_status_vars status_vars</td>
    <td>status_vars_len bytes</td>
    <td>Zero or more status variables.  Each status variable consists
    of one byte identifying the variable stored, followed by the value
    of the variable.  The possible variables are listed separately in
    the table @ref Table_query_log_event_status_vars "below".  MySQL
    always writes events in the order defined below; however, it is
    capable of reading them in any order.  </td>
  </tr>

  <tr>
    <td>db</td>
    <td>db_len+1</td>
    <td>The currently selected database, as a null-terminated string.

    (The trailing zero is redundant since the length is already known;
    it is db_len from Post-Header.)
    </td>
  </tr>

  <tr>
    <td>query</td>
    <td>variable length string without trailing zero, extending to the
    end of the event (determined by the length field of the
    Common-Header)
    </td>
    <td>The SQL query.</td>
  </tr>
  </table>

  The following table lists the status variables that may appear in
  the status_vars field.

  @anchor Table_query_log_event_status_vars
  <table>
  <caption>Status variables for Query_log_event</caption>

  <tr>
    <th>Status variable</th>
    <th>1 byte identifier</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>flags2</td>
    <td>Q_FLAGS2_CODE == 0</td>
    <td>4 byte bitfield</td>
    <td>The flags in @c session->options, binary AND-ed with @c
    OPTIONS_WRITTEN_TO_BIN_LOG.  The @c session->options bitfield contains
    options for "SELECT".  @c OPTIONS_WRITTEN identifies those options
    that need to be written to the binlog (not all do).  Specifically,
    @c OPTIONS_WRITTEN_TO_BIN_LOG equals (@c OPTION_AUTO_IS_NULL | @c
    OPTION_NO_FOREIGN_KEY_CHECKS | @c OPTION_RELAXED_UNIQUE_CHECKS |
    @c OPTION_NOT_AUTOCOMMIT), or 0x0c084000 in hex.

    These flags correspond to the SQL variables SQL_AUTO_IS_NULL,
    FOREIGN_KEY_CHECKS, UNIQUE_CHECKS, and AUTOCOMMIT, documented in
    the "SET Syntax" section of the MySQL Manual.

    This field is always written to the binlog in version >= 5.0, and
    never written in version < 5.0.
    </td>
  </tr>

  <tr>
    <td>sql_mode</td>
    <td>Q_SQL_MODE_CODE == 1</td>
    <td>8 byte bitfield</td>
    <td>The @c sql_mode variable.  See the section "SQL Modes" in the
    MySQL manual, and see mysql_priv.h for a list of the possible
    flags. Currently (2007-10-04), the following flags are available:
    <pre>
    MODE_REAL_AS_FLOAT==0x1
    MODE_PIPES_AS_CONCAT==0x2
    MODE_ANSI_QUOTES==0x4
    MODE_IGNORE_SPACE==0x8
    MODE_NOT_USED==0x10
    MODE_ONLY_FULL_GROUP_BY==0x20
    MODE_NO_UNSIGNED_SUBTRACTION==0x40
    MODE_NO_DIR_IN_CREATE==0x80
    MODE_POSTGRESQL==0x100
    MODE_ORACLE==0x200
    MODE_MSSQL==0x400
    MODE_DB2==0x800
    MODE_MAXDB==0x1000
    MODE_NO_KEY_OPTIONS==0x2000
    MODE_NO_TABLE_OPTIONS==0x4000
    MODE_NO_FIELD_OPTIONS==0x8000
    MODE_MYSQL323==0x10000
    MODE_MYSQL323==0x20000
    MODE_MYSQL40==0x40000
    MODE_ANSI==0x80000
    MODE_NO_AUTO_VALUE_ON_ZERO==0x100000
    MODE_NO_BACKSLASH_ESCAPES==0x200000
    MODE_STRICT_TRANS_TABLES==0x400000
    MODE_STRICT_ALL_TABLES==0x800000
    MODE_NO_ZERO_IN_DATE==0x1000000
    MODE_NO_ZERO_DATE==0x2000000
    MODE_INVALID_DATES==0x4000000
    MODE_ERROR_FOR_DIVISION_BY_ZERO==0x8000000
    MODE_TRADITIONAL==0x10000000
    MODE_NO_AUTO_CREATE_USER==0x20000000
    MODE_HIGH_NOT_PRECEDENCE==0x40000000
    MODE_PAD_CHAR_TO_FULL_LENGTH==0x80000000
    </pre>
    All these flags are replicated from the server.  However, all
    flags except @c MODE_NO_DIR_IN_CREATE are honored by the slave;
    the slave always preserves its old value of @c
    MODE_NO_DIR_IN_CREATE.  For a rationale, see comment in
    @c Query_log_event::do_apply_event in @c log_event.cc.

    This field is always written to the binlog.
    </td>
  </tr>

  <tr>
    <td>catalog</td>
    <td>Q_CATALOG_NZ_CODE == 6</td>
    <td>Variable-length string: the length in bytes (1 byte) followed
    by the characters (at most 255 bytes)
    </td>
    <td>Stores the client's current catalog.  Every database belongs
    to a catalog, the same way that every table belongs to a
    database.  Currently, there is only one catalog, "std".

    This field is written if the length of the catalog is > 0;
    otherwise it is not written.
    </td>
  </tr>

  <tr>
    <td>auto_increment</td>
    <td>Q_AUTO_INCREMENT == 3</td>
    <td>two 2 byte unsigned integers, totally 2+2=4 bytes</td>

    <td>The two variables auto_increment_increment and
    auto_increment_offset, in that order.  For more information, see
    "System variables" in the MySQL manual.

    This field is written if auto_increment > 1.  Otherwise, it is not
    written.
    </td>
  </tr>

  <tr>
    <td>charset</td>
    <td>Q_CHARSET_CODE == 4</td>
    <td>three 2 byte unsigned integers, totally 2+2+2=6 bytes</td>
    <td>The three variables character_set_client,
    collation_connection, and collation_server, in that order.
    character_set_client is a code identifying the character set and
    collation used by the client to encode the query.
    collation_connection identifies the character set and collation
    that the master converts the query to when it receives it; this is
    useful when comparing literal strings.  collation_server is the
    default character set and collation used when a new database is
    created.

    See also "Connection Character Sets and Collations" in the MySQL
    5.1 manual.

    All three variables are codes identifying a (character set,
    collation) pair.  To see which codes map to which pairs, run the
    query "SELECT id, character_set_name, collation_name FROM
    COLLATIONS".

    Cf. Q_CHARSET_DATABASE_CODE below.

    This field is always written.
    </td>
  </tr>

  <tr>
    <td>time_zone</td>
    <td>Q_TIME_ZONE_CODE == 5</td>
    <td>Variable-length string: the length in bytes (1 byte) followed
    by the characters (at most 255 bytes).
    <td>The time_zone of the master.

    See also "System Variables" and "MySQL Server Time Zone Support"
    in the MySQL manual.

    This field is written if the length of the time zone string is >
    0; otherwise, it is not written.
    </td>
  </tr>

  <tr>
    <td>lc_time_names_number</td>
    <td>Q_LC_TIME_NAMES_CODE == 7</td>
    <td>2 byte integer</td>
    <td>A code identifying a table of month and day names.  The
    mapping from codes to languages is defined in @c sql_locale.cc.

    This field is written if it is not 0, i.e., if the locale is not
    en_US.
    </td>
  </tr>

  <tr>
    <td>charset_database_number</td>
    <td>Q_CHARSET_DATABASE_CODE == 8</td>
    <td>2 byte integer</td>

    <td>The value of the collation_database system variable (in the
    source code stored in @c session->variables.collation_database), which
    holds the code for a (character set, collation) pair as described
    above (see Q_CHARSET_CODE).

    collation_database was used in old versions (???WHEN).  Its value
    was loaded when issuing a "use db" query and could be changed by
    issuing a "SET collation_database=xxx" query.  It used to affect
    the "LOAD DATA INFILE" and "CREATE TABLE" commands.

    In newer versions, "CREATE TABLE" has been changed to take the
    character set from the database of the created table, rather than
    the character set of the current database.  This makes a
    difference when creating a table in another database than the
    current one.  "LOAD DATA INFILE" has not yet changed to do this,
    but there are plans to eventually do it, and to make
    collation_database read-only.

    This field is written if it is not 0.
    </td>
  </tr>
  </table>

  @subsection Query_log_event_notes_on_previous_versions Notes on Previous Versions

  * Status vars were introduced in version 5.0.  To read earlier
  versions correctly, check the length of the Post-Header.

  * The status variable Q_CATALOG_CODE == 2 existed in MySQL 5.0.x,
  where 0<=x<=3.  It was identical to Q_CATALOG_CODE, except that the
  string had a trailing '\0'.  The '\0' was removed in 5.0.4 since it
  was redundant (the string length is stored before the string).  The
  Q_CATALOG_CODE will never be written by a new master, but can still
  be understood by a new slave.

  * See Q_CHARSET_DATABASE_CODE in the table above.

*/
class Query_log_event: public Log_event
{
protected:
  Log_event::Byte* data_buf;
public:
  const char* query;
  const char* catalog;
  const char* db;
  /*
    If we already know the length of the query string
    we pass it with q_len, so we would not have to call strlen()
    otherwise, set it to 0, in which case, we compute it with strlen()
  */
  uint32_t q_len;
  uint32_t db_len;
  uint16_t error_code;
  ulong thread_id;
  /*
    For events created by Query_log_event::do_apply_event (and
    Load_log_event::do_apply_event()) we need the *original* thread
    id, to be able to log the event with the original (=master's)
    thread id (fix for BUG#1686).
  */
  ulong slave_proxy_id;

  /*
    Binlog format 3 and 4 start to differ (as far as class members are
    concerned) from here.
  */

  uint32_t catalog_len;			// <= 255 char; 0 means uninited

  /*
    We want to be able to store a variable number of N-bit status vars:
    (generally N=32; but N=64 for SQL_MODE) a user may want to log the number
    of affected rows (for debugging) while another does not want to lose 4
    bytes in this.
    The storage on disk is the following:
    status_vars_len is part of the post-header,
    status_vars are in the variable-length part, after the post-header, before
    the db & query.
    status_vars on disk is a sequence of pairs (code, value) where 'code' means
    'sql_mode', 'affected' etc. Sometimes 'value' must be a short string, so
    its first byte is its length. For now the order of status vars is:
    flags2 - sql_mode - catalog - autoinc - charset
    We should add the same thing to Load_log_event, but in fact
    LOAD DATA INFILE is going to be logged with a new type of event (logging of
    the plain text query), so Load_log_event would be frozen, so no need. The
    new way of logging LOAD DATA INFILE would use a derived class of
    Query_log_event, so automatically benefit from the work already done for
    status variables in Query_log_event.
 */
  uint16_t status_vars_len;

  /*
    'flags2' is a second set of flags (on top of those in Log_event), for
    session variables. These are session->options which is & against a mask
    (OPTIONS_WRITTEN_TO_BIN_LOG).
    flags2_inited helps make a difference between flags2==0 (3.23 or 4.x
    master, we don't know flags2, so use the slave server's global options) and
    flags2==0 (5.0 master, we know this has a meaning of flags all down which
    must influence the query).
  */
  bool flags2_inited;
  bool sql_mode_inited;
  bool charset_inited;

  uint32_t flags2;
  /* In connections sql_mode is 32 bits now but will be 64 bits soon */
  ulong sql_mode;
  ulong auto_increment_increment, auto_increment_offset;
  char charset[6];
  uint32_t time_zone_len; /* 0 means uninited */
  const char *time_zone_str;
  uint32_t lc_time_names_number; /* 0 means en_US */
  uint32_t charset_database_number;


  Query_log_event(Session* session_arg, const char* query_arg, ulong query_length,
                  bool using_trans, bool suppress_use,
                  Session::killed_state killed_err_arg= Session::KILLED_NO_VALUE);
  const char* get_db() { return db; }
  void pack_info(Protocol* protocol);

  Query_log_event();
  Query_log_event(const char* buf, uint32_t event_len,
                  const Format_description_log_event *description_event,
                  Log_event_type event_type);
  ~Query_log_event()
  {
    if (data_buf)
      free((unsigned char*) data_buf);
  }
  Log_event_type get_type_code() { return QUERY_EVENT; }
  bool write(IO_CACHE* file);
  virtual bool write_post_header_for_derived(IO_CACHE*)
  { return false; }
  bool is_valid() const { return query != 0; }

  /*
    Returns number of bytes additionaly written to post header by derived
    events (so far it is only Execute_load_query event).
  */
  virtual ulong get_post_header_size_for_derived() { return 0; }
  /* Writes derived event-specific part of post header. */

public:        /* !!! Public in this patch to allow old usage */
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);
  virtual int do_apply_event(Relay_log_info const *rli);
  virtual int do_update_pos(Relay_log_info *rli);

  int do_apply_event(Relay_log_info const *rli,
                       const char *query_arg,
                       uint32_t q_len_arg);
};


/**
  @class Slave_log_event

  Note that this class is currently not used at all; no code writes a
  @c Slave_log_event (though some code in @c repl_failsafe.cc reads @c
  Slave_log_event).  So it's not a problem if this code is not
  maintained.

  @section Slave_log_event_binary_format Binary Format

  This event type has no Post-Header. The Body has the following
  four components.

  <table>
  <caption>Body for Slave_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>master_pos</td>
    <td>8 byte integer</td>
    <td>???TODO
    </td>
  </tr>

  <tr>
    <td>master_port</td>
    <td>2 byte integer</td>
    <td>???TODO</td>
  </tr>

  <tr>
    <td>master_host</td>
    <td>null-terminated string</td>
    <td>???TODO</td>
  </tr>

  <tr>
    <td>master_log</td>
    <td>null-terminated string</td>
    <td>???TODO</td>
  </tr>
  </table>
*/

class Slave_log_event: public Log_event
{
protected:
  char* mem_pool;
  void init_from_mem_pool();
public:
  off_t master_pos;
  std::string master_host;
  std::string master_log;
  uint16_t master_port;

  Slave_log_event(Session* session_arg, Relay_log_info* rli);
  void pack_info(Protocol* protocol);

  Slave_log_event(const char* buf, uint32_t event_len);
  ~Slave_log_event();
  int get_data_size();
  bool is_valid() const { return master_host.length() != 0; }
  Log_event_type get_type_code() { return SLAVE_EVENT; }
  bool write(IO_CACHE* file);

private:
  virtual int do_apply_event(Relay_log_info const* rli);
};


/**
  @class Load_log_event

  This log event corresponds to a "LOAD DATA INFILE" SQL query on the
  following form:

  @verbatim
   (1)    USE db;
   (2)    LOAD DATA [LOCAL] INFILE 'file_name'
   (3)    [REPLACE | IGNORE]
   (4)    INTO Table 'table_name'
   (5)    [FIELDS
   (6)      [TERMINATED BY 'field_term']
   (7)      [[OPTIONALLY] ENCLOSED BY 'enclosed']
   (8)      [ESCAPED BY 'escaped']
   (9)    ]
  (10)    [LINES
  (11)      [TERMINATED BY 'line_term']
  (12)      [LINES STARTING BY 'line_start']
  (13)    ]
  (14)    [IGNORE skip_lines LINES]
  (15)    (field_1, field_2, ..., field_n)@endverbatim

  @section Load_log_event_binary_format Binary Format

  The Post-Header consists of the following six components.

  <table>
  <caption>Post-Header for Load_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>slave_proxy_id</td>
    <td>4 byte unsigned integer</td>
    <td>An integer identifying the client thread that issued the
    query.  The id is unique per server.  (Note, however, that two
    threads on different servers may have the same slave_proxy_id.)
    This is used when a client thread creates a temporary table local
    to the client.  The slave_proxy_id is used to distinguish
    temporary tables that belong to different clients.
    </td>
  </tr>

  <tr>
    <td>exec_time</td>
    <td>4 byte unsigned integer</td>
    <td>The time from when the query started to when it was logged in
    the binlog, in seconds.</td>
  </tr>

  <tr>
    <td>skip_lines</td>
    <td>4 byte unsigned integer</td>
    <td>The number on line (14) above, if present, or 0 if line (14)
    is left out.
    </td>
  </tr>

  <tr>
    <td>table_name_len</td>
    <td>1 byte unsigned integer</td>
    <td>The length of 'table_name' on line (4) above.</td>
  </tr>

  <tr>
    <td>db_len</td>
    <td>1 byte unsigned integer</td>
    <td>The length of 'db' on line (1) above.</td>
  </tr>

  <tr>
    <td>num_fields</td>
    <td>4 byte unsigned integer</td>
    <td>The number n of fields on line (15) above.</td>
  </tr>
  </table>    

  The Body contains the following components.

  <table>
  <caption>Body of Load_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>sql_ex</td>
    <td>variable length</td>

    <td>Describes the part of the query on lines (3) and
    (5)&ndash;(13) above.  More precisely, it stores the five strings
    (on lines) field_term (6), enclosed (7), escaped (8), line_term
    (11), and line_start (12); as well as a bitfield indicating the
    presence of the keywords REPLACE (3), IGNORE (3), and OPTIONALLY
    (7).

    The data is stored in one of two formats, called "old" and "new".
    The type field of Common-Header determines which of these two
    formats is used: type LOAD_EVENT means that the old format is
    used, and type NEW_LOAD_EVENT means that the new format is used.
    When MySQL writes a Load_log_event, it uses the new format if at
    least one of the five strings is two or more bytes long.
    Otherwise (i.e., if all strings are 0 or 1 bytes long), the old
    format is used.

    The new and old format differ in the way the five strings are
    stored.

    <ul>
    <li> In the new format, the strings are stored in the order
    field_term, enclosed, escaped, line_term, line_start. Each string
    consists of a length (1 byte), followed by a sequence of
    characters (0-255 bytes).  Finally, a boolean combination of the
    following flags is stored in 1 byte: REPLACE_FLAG==0x4,
    IGNORE_FLAG==0x8, and OPT_ENCLOSED_FLAG==0x2.  If a flag is set,
    it indicates the presence of the corresponding keyword in the SQL
    query.

    <li> In the old format, we know that each string has length 0 or
    1.  Therefore, only the first byte of each string is stored.  The
    order of the strings is the same as in the new format.  These five
    bytes are followed by the same 1 byte bitfield as in the new
    format.  Finally, a 1 byte bitfield called empty_flags is stored.
    The low 5 bits of empty_flags indicate which of the five strings
    have length 0.  For each of the following flags that is set, the
    corresponding string has length 0; for the flags that are not set,
    the string has length 1: FIELD_TERM_EMPTY==0x1,
    ENCLOSED_EMPTY==0x2, LINE_TERM_EMPTY==0x4, LINE_START_EMPTY==0x8,
    ESCAPED_EMPTY==0x10.
    </ul>

    Thus, the size of the new format is 6 bytes + the sum of the sizes
    of the five strings.  The size of the old format is always 7
    bytes.
    </td>
  </tr>

  <tr>
    <td>field_lens</td>
    <td>num_fields 1 byte unsigned integers</td>
    <td>An array of num_fields integers representing the length of
    each field in the query.  (num_fields is from the Post-Header).
    </td>
  </tr>

  <tr>
    <td>fields</td>
    <td>num_fields null-terminated strings</td>
    <td>An array of num_fields null-terminated strings, each
    representing a field in the query.  (The trailing zero is
    redundant, since the length are stored in the num_fields array.)
    The total length of all strings equals to the sum of all
    field_lens, plus num_fields bytes for all the trailing zeros.
    </td>
  </tr>

  <tr>
    <td>table_name</td>
    <td>null-terminated string of length table_len+1 bytes</td>
    <td>The 'table_name' from the query, as a null-terminated string.
    (The trailing zero is actually redundant since the table_len is
    known from Post-Header.)
    </td>
  </tr>

  <tr>
    <td>db</td>
    <td>null-terminated string of length db_len+1 bytes</td>
    <td>The 'db' from the query, as a null-terminated string.
    (The trailing zero is actually redundant since the db_len is known
    from Post-Header.)
    </td>
  </tr>

  <tr>
    <td>file_name</td>
    <td>variable length string without trailing zero, extending to the
    end of the event (determined by the length field of the
    Common-Header)
    </td>
    <td>The 'file_name' from the query.
    </td>
  </tr>

  </table>

  @subsection Load_log_event_notes_on_previous_versions Notes on Previous Versions

  This event type is understood by current versions, but only
  generated by MySQL 3.23 and earlier.
*/
class Load_log_event: public Log_event
{
private:
  uint32_t get_query_buffer_length();
  void print_query(bool need_db, char *buf, char **end,
                   char **fn_start, char **fn_end);
protected:
  int copy_log_event(const char *buf, ulong event_len,
                     int body_offset,
                     const Format_description_log_event* description_event);

public:
  ulong thread_id;
  ulong slave_proxy_id;
  uint32_t table_name_len;
  /*
    No need to have a catalog, as these events can only come from 4.x.
    TODO: this may become false if Dmitri pushes his new LOAD DATA INFILE in
    5.0 only (not in 4.x).
  */
  uint32_t db_len;
  uint32_t fname_len;
  uint32_t num_fields;
  const char* fields;
  const unsigned char* field_lens;
  uint32_t field_block_len;

  const char* table_name;
  const char* db;
  const char* fname;
  uint32_t skip_lines;
  sql_ex_info sql_ex;
  bool local_fname;

  /* fname doesn't point to memory inside Log_event::temp_buf  */
  void set_fname_outside_temp_buf(const char *afname, uint32_t alen)
  {
    fname= afname;
    fname_len= alen;
    local_fname= true;
  }
  /* fname doesn't point to memory inside Log_event::temp_buf  */
  int  check_fname_outside_temp_buf()
  {
    return local_fname;
  }

  String field_lens_buf;
  String fields_buf;

  Load_log_event(Session* session, sql_exchange* ex, const char* db_arg,
		 const char* table_name_arg,
		 List<Item>& fields_arg, enum enum_duplicates handle_dup, bool ignore,
		 bool using_trans);
  void set_fields(const char* db, List<Item> &fields_arg,
                  Name_resolution_context *context);
  const char* get_db() { return db; }
  void pack_info(Protocol* protocol);

  /*
    Note that for all the events related to LOAD DATA (Load_log_event,
    Create_file/Append/Exec/Delete, we pass description_event; however as
    logging of LOAD DATA is going to be changed in 4.1 or 5.0, this is only used
    for the common_header_len (post_header_len will not be changed).
  */
  Load_log_event(const char* buf, uint32_t event_len,
                 const Format_description_log_event* description_event);
  ~Load_log_event()
  {}
  Log_event_type get_type_code()
  {
    return sql_ex.new_format() ? NEW_LOAD_EVENT: LOAD_EVENT;
  }
  bool write_data_header(IO_CACHE* file);
  bool write_data_body(IO_CACHE* file);
  bool is_valid() const { return table_name != 0; }
  int get_data_size()
  {
    return (table_name_len + db_len + 2 + fname_len
	    + LOAD_HEADER_LEN
	    + sql_ex.data_size() + field_block_len + num_fields);
  }

public:        /* !!! Public in this patch to allow old usage */
  virtual int do_apply_event(Relay_log_info const* rli)
  {
    return do_apply_event(session->slave_net,rli,0);
  }

  int do_apply_event(NET *net, Relay_log_info const *rli,
                     bool use_rli_only_for_errors);
};

extern char server_version[SERVER_VERSION_LENGTH];

/**
  @class Start_log_event_v3

  Start_log_event_v3 is the Start_log_event of binlog format 3 (MySQL 3.23 and
  4.x).

  Format_description_log_event derives from Start_log_event_v3; it is
  the Start_log_event of binlog format 4 (MySQL 5.0), that is, the
  event that describes the other events' Common-Header/Post-Header
  lengths. This event is sent by MySQL 5.0 whenever it starts sending
  a new binlog if the requested position is >4 (otherwise if ==4 the
  event will be sent naturally).

  @section Start_log_event_v3_binary_format Binary Format
*/
class Start_log_event_v3: public Log_event
{
public:
  /*
    If this event is at the start of the first binary log since server
    startup 'created' should be the timestamp when the event (and the
    binary log) was created.  In the other case (i.e. this event is at
    the start of a binary log created by FLUSH LOGS or automatic
    rotation), 'created' should be 0.  This "trick" is used by MySQL
    >=4.0.14 slaves to know whether they must drop stale temporary
    tables and whether they should abort unfinished transaction.

    Note that when 'created'!=0, it is always equal to the event's
    timestamp; indeed Start_log_event is written only in log.cc where
    the first constructor below is called, in which 'created' is set
    to 'when'.  So in fact 'created' is a useless variable. When it is
    0 we can read the actual value from timestamp ('when') and when it
    is non-zero we can read the same value from timestamp
    ('when'). Conclusion:
     - we use timestamp to print when the binlog was created.
     - we use 'created' only to know if this is a first binlog or not.
     In 3.23.57 we did not pay attention to this identity, so mysqlbinlog in
     3.23.57 does not print 'created the_date' if created was zero. This is now
     fixed.
  */
  time_t created;
  uint16_t binlog_version;
  char server_version[ST_SERVER_VER_LEN];
  /*
    artifical_event is 1 in the case where this is a generated event that
    should not case any cleanup actions. We handle this in the log by
    setting log_event == 0 (for now).
  */
  bool artificial_event;
  /*
    We set this to 1 if we don't want to have the created time in the log,
    which is the case when we rollover to a new log.
  */
  bool dont_set_created;

  Start_log_event_v3();
  void pack_info(Protocol* protocol);

  Start_log_event_v3(const char* buf,
                     const Format_description_log_event* description_event);
  ~Start_log_event_v3() {}
  Log_event_type get_type_code() { return START_EVENT_V3;}
  bool write(IO_CACHE* file);
  bool is_valid() const { return 1; }
  int get_data_size()
  {
    return START_V3_HEADER_LEN; //no variable-sized part
  }
  virtual bool is_artificial_event() { return artificial_event; }

protected:
  virtual int do_apply_event(Relay_log_info const *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info*)
  {
    /*
      Events from ourself should be skipped, but they should not
      decrease the slave skip counter.
     */
    if (this->server_id == ::server_id)
      return Log_event::EVENT_SKIP_IGNORE;
    else
      return Log_event::EVENT_SKIP_NOT;
  }
};


/**
  @class Format_description_log_event

  For binlog version 4.
  This event is saved by threads which read it, as they need it for future
  use (to decode the ordinary events).

  @section Format_description_log_event_binary_format Binary Format
*/

class Format_description_log_event: public Start_log_event_v3
{
public:
  /*
     The size of the fixed header which _all_ events have
     (for binlogs written by this version, this is equal to
     LOG_EVENT_HEADER_LEN), except FORMAT_DESCRIPTION_EVENT and ROTATE_EVENT
     (those have a header of size LOG_EVENT_MINIMAL_HEADER_LEN).
  */
  uint8_t common_header_len;
  uint8_t number_of_event_types;
  /* The list of post-headers' lengthes */
  uint8_t *post_header_len;
  unsigned char server_version_split[3];
  const uint8_t *event_type_permutation;

  Format_description_log_event(uint8_t binlog_ver, const char* server_ver=0);
  Format_description_log_event(const char* buf, uint32_t event_len,
                               const Format_description_log_event
                               *description_event);
  ~Format_description_log_event()
  {
    free((unsigned char*)post_header_len);
  }
  Log_event_type get_type_code() { return FORMAT_DESCRIPTION_EVENT;}
  bool write(IO_CACHE* file);
  bool is_valid() const
  {
    return ((common_header_len >= ((binlog_version==1) ? OLD_HEADER_LEN :
                                   LOG_EVENT_MINIMAL_HEADER_LEN)) &&
            (post_header_len != NULL));
  }
  int get_data_size()
  {
    /*
      The vector of post-header lengths is considered as part of the
      post-header, because in a given version it never changes (contrary to the
      query in a Query_log_event).
    */
    return FORMAT_DESCRIPTION_HEADER_LEN;
  }

  void calc_server_version_split();

protected:
  virtual int do_apply_event(Relay_log_info const *rli);
  virtual int do_update_pos(Relay_log_info *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);
};

/**
  @class Xid_log_event

  Logs xid of the transaction-to-be-committed in the 2pc protocol.
  Has no meaning in replication, slaves ignore it.

  @section Xid_log_event_binary_format Binary Format  
*/
class Xid_log_event: public Log_event
{
 public:
   my_xid xid;

  Xid_log_event(Session* session_arg, my_xid x): Log_event(session_arg,0,0), xid(x) {}
  void pack_info(Protocol* protocol);

  Xid_log_event(const char* buf,
                const Format_description_log_event *description_event);
  ~Xid_log_event() {}
  Log_event_type get_type_code() { return XID_EVENT;}
  int get_data_size() { return sizeof(xid); }
  bool write(IO_CACHE* file);
  bool is_valid() const { return 1; }

private:
  virtual int do_apply_event(Relay_log_info const *rli);
  enum_skip_reason do_shall_skip(Relay_log_info *rli);
};


/**
  @class Stop_log_event

  @section Stop_log_event_binary_format Binary Format

  The Post-Header and Body for this event type are empty; it only has
  the Common-Header.
*/
class Stop_log_event: public Log_event
{
public:
  Stop_log_event() :Log_event()
  {}

  Stop_log_event(const char* buf,
                 const Format_description_log_event *description_event):
    Log_event(buf, description_event)
  {}
  ~Stop_log_event() {}
  Log_event_type get_type_code() { return STOP_EVENT;}
  bool is_valid() const { return 1; }

private:
  virtual int do_update_pos(Relay_log_info *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info *)
  {
    /*
      Events from ourself should be skipped, but they should not
      decrease the slave skip counter.
     */
    if (this->server_id == ::server_id)
      return Log_event::EVENT_SKIP_IGNORE;
    else
      return Log_event::EVENT_SKIP_NOT;
  }
};

/**
  @class Rotate_log_event

  This will be deprecated when we move to using sequence ids.

  @section Rotate_log_event_binary_format Binary Format

  The Post-Header has one component:

  <table>
  <caption>Post-Header for Rotate_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>position</td>
    <td>8 byte integer</td>
    <td>The position within the binlog to rotate to.</td>
  </tr>

  </table>

  The Body has one component:

  <table>
  <caption>Body for Rotate_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>new_log</td>
    <td>variable length string without trailing zero, extending to the
    end of the event (determined by the length field of the
    Common-Header)
    </td>
    <td>Name of the binlog to rotate to.</td>
  </tr>

  </table>
*/

class Rotate_log_event: public Log_event
{
public:
  enum {
    DUP_NAME= 2 // if constructor should dup the string argument
  };
  const char* new_log_ident;
  uint64_t pos;
  uint32_t ident_len;
  uint32_t flags;
  Rotate_log_event(const char* new_log_ident_arg,
		   uint32_t ident_len_arg,
		   uint64_t pos_arg, uint32_t flags);
  void pack_info(Protocol* protocol);

  Rotate_log_event(const char* buf, uint32_t event_len,
                   const Format_description_log_event* description_event);
  ~Rotate_log_event()
  {
    if (flags & DUP_NAME)
      free((unsigned char*) new_log_ident);
  }
  Log_event_type get_type_code() { return ROTATE_EVENT;}
  int get_data_size() { return  ident_len + ROTATE_HEADER_LEN;}
  bool is_valid() const { return new_log_ident != 0; }
  bool write(IO_CACHE* file);

private:
  virtual int do_update_pos(Relay_log_info *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);
};


/* the classes below are for the new LOAD DATA INFILE logging */

/**
  @class Create_file_log_event

  @section Create_file_log_event_binary_format Binary Format
*/

class Create_file_log_event: public Load_log_event
{
protected:
  /*
    Pretend we are Load event, so we can write out just
    our Load part - used on the slave when writing event out to
    SQL_LOAD-*.info file
  */
  bool fake_base;
public:
  unsigned char* block;
  const char *event_buf;
  uint32_t block_len;
  uint32_t file_id;
  bool inited_from_old;

  Create_file_log_event(Session* session, sql_exchange* ex, const char* db_arg,
			const char* table_name_arg,
			List<Item>& fields_arg,
			enum enum_duplicates handle_dup, bool ignore,
			unsigned char* block_arg, uint32_t block_len_arg,
			bool using_trans);
  void pack_info(Protocol* protocol);

  Create_file_log_event(const char* buf, uint32_t event_len,
                        const Format_description_log_event* description_event);
  ~Create_file_log_event()
  {
    free((char*) event_buf);
  }

  Log_event_type get_type_code()
  {
    return fake_base ? Load_log_event::get_type_code() : CREATE_FILE_EVENT;
  }
  int get_data_size()
  {
    return (fake_base ? Load_log_event::get_data_size() :
	    Load_log_event::get_data_size() +
	    4 + 1 + block_len);
  }
  bool is_valid() const { return inited_from_old || block != 0; }
  bool write_data_header(IO_CACHE* file);
  bool write_data_body(IO_CACHE* file);
  /*
    Cut out Create_file extentions and
    write it as Load event - used on the slave
  */
  bool write_base(IO_CACHE* file);

private:
  virtual int do_apply_event(Relay_log_info const *rli);
};


/**
  @class Append_block_log_event

  @section Append_block_log_event_binary_format Binary Format
*/

class Append_block_log_event: public Log_event
{
public:
  unsigned char* block;
  uint32_t block_len;
  uint32_t file_id;
  /*
    'db' is filled when the event is created in mysql_load() (the
    event needs to have a 'db' member to be well filtered by
    binlog-*-db rules). 'db' is not written to the binlog (it's not
    used by Append_block_log_event::write()), so it can't be read in
    the Append_block_log_event(const char* buf, int event_len)
    constructor.  In other words, 'db' is used only for filtering by
    binlog-*-db rules.  Create_file_log_event is different: it's 'db'
    (which is inherited from Load_log_event) is written to the binlog
    and can be re-read.
  */
  const char* db;

  Append_block_log_event(Session* session, const char* db_arg, unsigned char* block_arg,
			 uint32_t block_len_arg, bool using_trans);
  void pack_info(Protocol* protocol);
  virtual int get_create_or_append() const;

  Append_block_log_event(const char* buf, uint32_t event_len,
                         const Format_description_log_event
                         *description_event);
  ~Append_block_log_event() {}
  Log_event_type get_type_code() { return APPEND_BLOCK_EVENT;}
  int get_data_size() { return  block_len + APPEND_BLOCK_HEADER_LEN ;}
  bool is_valid() const { return block != 0; }
  bool write(IO_CACHE* file);
  const char* get_db() { return db; }

private:
  virtual int do_apply_event(Relay_log_info const *rli);
};


/**
  @class Delete_file_log_event

  @section Delete_file_log_event_binary_format Binary Format
*/

class Delete_file_log_event: public Log_event
{
public:
  uint32_t file_id;
  const char* db; /* see comment in Append_block_log_event */

  Delete_file_log_event(Session* session, const char* db_arg, bool using_trans);
  void pack_info(Protocol* protocol);

  Delete_file_log_event(const char* buf, uint32_t event_len,
                        const Format_description_log_event* description_event);
  ~Delete_file_log_event() {}
  Log_event_type get_type_code() { return DELETE_FILE_EVENT;}
  int get_data_size() { return DELETE_FILE_HEADER_LEN ;}
  bool is_valid() const { return file_id != 0; }
  bool write(IO_CACHE* file);
  const char* get_db() { return db; }

private:
  virtual int do_apply_event(Relay_log_info const *rli);
};


/**
  @class Execute_load_log_event

  @section Delete_file_log_event_binary_format Binary Format
*/

class Execute_load_log_event: public Log_event
{
public:
  uint32_t file_id;
  const char* db; /* see comment in Append_block_log_event */

  Execute_load_log_event(Session* session, const char* db_arg, bool using_trans);
  void pack_info(Protocol* protocol);

  Execute_load_log_event(const char* buf, uint32_t event_len,
                         const Format_description_log_event
                         *description_event);
  ~Execute_load_log_event() {}
  Log_event_type get_type_code() { return EXEC_LOAD_EVENT;}
  int get_data_size() { return  EXEC_LOAD_HEADER_LEN ;}
  bool is_valid() const { return file_id != 0; }
  bool write(IO_CACHE* file);
  const char* get_db() { return db; }

private:
  virtual int do_apply_event(Relay_log_info const *rli);
};


/**
  @class Begin_load_query_log_event

  Event for the first block of file to be loaded, its only difference from
  Append_block event is that this event creates or truncates existing file
  before writing data.

  @section Begin_load_query_log_event_binary_format Binary Format
*/
class Begin_load_query_log_event: public Append_block_log_event
{
public:
  Begin_load_query_log_event(Session* session_arg, const char *db_arg,
                             unsigned char* block_arg, uint32_t block_len_arg,
                             bool using_trans);
  Begin_load_query_log_event(Session* session);
  int get_create_or_append() const;
  Begin_load_query_log_event(const char* buf, uint32_t event_len,
                             const Format_description_log_event
                             *description_event);
  ~Begin_load_query_log_event() {}
  Log_event_type get_type_code() { return BEGIN_LOAD_QUERY_EVENT; }
private:
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);
};


/*
  Elements of this enum describe how LOAD DATA handles duplicates.
*/
enum enum_load_dup_handling { LOAD_DUP_ERROR= 0, LOAD_DUP_IGNORE,
                              LOAD_DUP_REPLACE };

/**
  @class Execute_load_query_log_event

  Event responsible for LOAD DATA execution, it similar to Query_log_event
  but before executing the query it substitutes original filename in LOAD DATA
  query with name of temporary file.

  @section Execute_load_query_log_event_binary_format Binary Format
*/
class Execute_load_query_log_event: public Query_log_event
{
public:
  uint32_t file_id;       // file_id of temporary file
  uint32_t fn_pos_start;  // pointer to the part of the query that should
                      // be substituted
  uint32_t fn_pos_end;    // pointer to the end of this part of query
  /*
    We have to store type of duplicate handling explicitly, because
    for LOAD DATA it also depends on LOCAL option. And this part
    of query will be rewritten during replication so this information
    may be lost...
  */
  enum_load_dup_handling dup_handling;

  Execute_load_query_log_event(Session* session, const char* query_arg,
                               ulong query_length, uint32_t fn_pos_start_arg,
                               uint32_t fn_pos_end_arg,
                               enum_load_dup_handling dup_handling_arg,
                               bool using_trans, bool suppress_use,
                               Session::killed_state
                               killed_err_arg= Session::KILLED_NO_VALUE);
  void pack_info(Protocol* protocol);
  Execute_load_query_log_event(const char* buf, uint32_t event_len,
                               const Format_description_log_event
                               *description_event);
  ~Execute_load_query_log_event() {}

  Log_event_type get_type_code() { return EXECUTE_LOAD_QUERY_EVENT; }
  bool is_valid() const { return Query_log_event::is_valid() && file_id != 0; }

  ulong get_post_header_size_for_derived();
  bool write_post_header_for_derived(IO_CACHE* file);

private:
  virtual int do_apply_event(Relay_log_info const *rli);
};


char *str_to_hex(char *to, const char *from, uint32_t len);

/**
  @class Table_map_log_event

  In row-based mode, every row operation event is preceded by a
  Table_map_log_event which maps a table definition to a number.  The
  table definition consists of database name, table name, and column
  definitions.

  @section Table_map_log_event_binary_format Binary Format

  The Post-Header has the following components:

  <table>
  <caption>Post-Header for Table_map_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>table_id</td>
    <td>6 bytes unsigned integer</td>
    <td>The number that identifies the table.</td>
  </tr>

  <tr>
    <td>flags</td>
    <td>2 byte bitfield</td>
    <td>Reserved for future use; currently always 0.</td>
  </tr>

  </table>

  The Body has the following components:

  <table>
  <caption>Body for Table_map_log_event</caption>

  <tr>
    <th>Name</th>
    <th>Format</th>
    <th>Description</th>
  </tr>

  <tr>
    <td>database_name</td>
    <td>one byte string length, followed by null-terminated string</td>
    <td>The name of the database in which the table resides.  The name
    is represented as a one byte unsigned integer representing the
    number of bytes in the name, followed by length bytes containing
    the database name, followed by a terminating 0 byte.  (Note the
    redundancy in the representation of the length.)  </td>
  </tr>

  <tr>
    <td>table_name</td>
    <td>one byte string length, followed by null-terminated string</td>
    <td>The name of the table, encoded the same way as the database
    name above.</td>
  </tr>

  <tr>
    <td>column_count</td>
    <td>@ref packed_integer "Packed Integer"</td>
    <td>The number of columns in the table, represented as a packed
    variable-length integer.</td>
  </tr>

  <tr>
    <td>column_type</td>
    <td>List of column_count 1 byte enumeration values</td>
    <td>The type of each column in the table, listed from left to
    right.  Each byte is mapped to a column type according to the
    enumeration type enum_field_types defined in mysql_com.h.  The
    mapping of types to numbers is listed in the table @ref
    Table_table_map_log_event_column_types "below" (along with
    description of the associated metadata field).  </td>
  </tr>

  <tr>
    <td>metadata_length</td>
    <td>@ref packed_integer "Packed Integer"</td>
    <td>The length of the following metadata block</td>
  </tr>

  <tr>
    <td>metadata</td>
    <td>list of metadata for each column</td>
    <td>For each column from left to right, a chunk of data who's
    length and semantics depends on the type of the column.  The
    length and semantics for the metadata for each column are listed
    in the table @ref Table_table_map_log_event_column_types
    "below".</td>
  </tr>

  <tr>
    <td>null_bits</td>
    <td>column_count bits, rounded up to nearest byte</td>
    <td>For each column, a bit indicating whether data in the column
    can be NULL or not.  The number of bytes needed for this is
    int((column_count+7)/8).  The flag for the first column from the
    left is in the least-significant bit of the first byte, the second
    is in the second least significant bit of the first byte, the
    ninth is in the least significant bit of the second byte, and so
    on.  </td>
  </tr>

  </table>

  The table below lists all column types, along with the numerical
  identifier for it and the size and interpretation of meta-data used
  to describe the type.

  @anchor Table_table_map_log_event_column_types
  <table>
  <caption>Table_map_log_event column types: numerical identifier and
  metadata</caption>
  <tr>
    <th>Name</th>
    <th>Identifier</th>
    <th>Size of metadata in bytes</th>
    <th>Description of metadata</th>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_TINY</td><td>1</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_SHORT</td><td>2</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_LONG</td><td>3</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_DOUBLE</td><td>5</td>
    <td>1 byte</td>
    <td>1 byte unsigned integer, representing the "pack_length", which
    is equal to sizeof(double) on the server from which the event
    originates.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_NULL</td><td>6</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_TIMESTAMP</td><td>7</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_LONGLONG</td><td>8</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_DATE</td><td>10</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_TIME</td><td>11</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_DATETIME</td><td>12</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_YEAR</td><td>13</td>
    <td>0</td>
    <td>No column metadata.</td>
  </tr>

  <tr>
    <td><i>DRIZZLE_TYPE_DATE</i></td><td><i>14</i></td>
    <td>&ndash;</td>
    <td><i>This enumeration value is only used internally and cannot
    exist in a binlog.</i></td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_VARCHAR</td><td>15</td>
    <td>2 bytes</td>
    <td>2 byte unsigned integer representing the maximum length of
    the string.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_NEWDECIMAL</td><td>246</td>
    <td>2 bytes</td>
    <td>A 1 byte unsigned int representing the precision, followed
    by a 1 byte unsigned int representing the number of decimals.</td>
  </tr>

  <tr>
    <td><i>DRIZZLE_TYPE_ENUM</i></td><td><i>247</i></td>
    <td>&ndash;</td>
    <td><i>This enumeration value is only used internally and cannot
    exist in a binlog.</i></td>
  </tr>

  <tr>
    <td><i>DRIZZLE_TYPE_SET</i></td><td><i>248</i></td>
    <td>&ndash;</td>
    <td><i>This enumeration value is only used internally and cannot
    exist in a binlog.</i></td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_BLOB</td><td>252</td>
    <td>1 byte</td>
    <td>The pack length, i.e., the number of bytes needed to represent
    the length of the blob: 1, 2, 3, or 4.</td>
  </tr>

  <tr>
    <td>DRIZZLE_TYPE_STRING</td><td>254</td>
    <td>2 bytes</td>
    <td>The first byte is always DRIZZLE_TYPE_VAR_STRING (i.e., 253).
    The second byte is the field size, i.e., the number of bytes in
    the representation of size of the string: 3 or 4.</td>
  </tr>

  </table>
*/
class Table_map_log_event : public Log_event
{
public:
  /* Constants */
  enum
  {
    TYPE_CODE = TABLE_MAP_EVENT
  };

  /**
     Enumeration of the errors that can be returned.
   */
  enum enum_error
  {
    ERR_OPEN_FAILURE = -1,               /**< Failure to open table */
    ERR_OK = 0,                                 /**< No error */
    ERR_TABLE_LIMIT_EXCEEDED = 1,      /**< No more room for tables */
    ERR_OUT_OF_MEM = 2,                         /**< Out of memory */
    ERR_BAD_TABLE_DEF = 3,     /**< Table definition does not match */
    ERR_RBR_TO_SBR = 4  /**< daisy-chanining RBR to SBR not allowed */
  };

  enum enum_flag
  {
    /* 
       Nothing here right now, but the flags support is there in
       preparation for changes that are coming.  Need to add a
       constant to make it compile under HP-UX: aCC does not like
       empty enumerations.
    */
    ENUM_FLAG_COUNT
  };

  typedef uint16_t flag_set;

  /* Special constants representing sets of flags */
  enum 
  {
    TM_NO_FLAGS = 0U
  };

  void set_flags(flag_set flag) { m_flags |= flag; }
  void clear_flags(flag_set flag) { m_flags &= ~flag; }
  flag_set get_flags(flag_set flag) const { return m_flags & flag; }

  Table_map_log_event(Session *session, Table *tbl, ulong tid, 
		      bool is_transactional, uint16_t flags);
  Table_map_log_event(const char *buf, uint32_t event_len, 
                      const Format_description_log_event *description_event);

  ~Table_map_log_event();

  virtual Log_event_type get_type_code() { return TABLE_MAP_EVENT; }
  virtual bool is_valid() const { return m_memory != NULL; /* we check malloc */ }

  virtual int get_data_size() { return m_data_size; } 
  virtual int save_field_metadata();
  virtual bool write_data_header(IO_CACHE *file);
  virtual bool write_data_body(IO_CACHE *file);
  virtual const char *get_db() { return m_dbnam; }
  virtual void pack_info(Protocol *protocol);

private:
  virtual int do_apply_event(Relay_log_info const *rli);
  virtual int do_update_pos(Relay_log_info *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);

  Table         *m_table;
  char const    *m_dbnam;
  size_t         m_dblen;
  char const    *m_tblnam;
  size_t         m_tbllen;
  ulong          m_colcnt;
  unsigned char         *m_coltype;

  unsigned char         *m_memory;
  ulong          m_table_id;
  flag_set       m_flags;

  size_t         m_data_size;

  unsigned char          *m_field_metadata;        // buffer for field metadata
  /*
    The size of field metadata buffer set by calling save_field_metadata()
  */
  ulong          m_field_metadata_size;   
  unsigned char         *m_null_bits;
  unsigned char         *m_meta_memory;
};


/**
  @class Rows_log_event

 Common base class for all row-containing log events.

 RESPONSIBILITIES

   Encode the common parts of all events containing rows, which are:
   - Write data header and data body to an IO_CACHE.
   - Provide an interface for adding an individual row to the event.

  @section Rows_log_event_binary_format Binary Format
*/


class Rows_log_event : public Log_event
{
public:
  /**
     Enumeration of the errors that can be returned.
   */
  enum enum_error
  {
    ERR_OPEN_FAILURE = -1,               /**< Failure to open table */
    ERR_OK = 0,                                 /**< No error */
    ERR_TABLE_LIMIT_EXCEEDED = 1,      /**< No more room for tables */
    ERR_OUT_OF_MEM = 2,                         /**< Out of memory */
    ERR_BAD_TABLE_DEF = 3,     /**< Table definition does not match */
    ERR_RBR_TO_SBR = 4  /**< daisy-chanining RBR to SBR not allowed */
  };

  /*
    These definitions allow you to combine the flags into an
    appropriate flag set using the normal bitwise operators.  The
    implicit conversion from an enum-constant to an integer is
    accepted by the compiler, which is then used to set the real set
    of flags.
  */
  enum enum_flag
  {
    /* Last event of a statement */
    STMT_END_F = (1U << 0),

    /* Value of the OPTION_NO_FOREIGN_KEY_CHECKS flag in session->options */
    NO_FOREIGN_KEY_CHECKS_F = (1U << 1),

    /* Value of the OPTION_RELAXED_UNIQUE_CHECKS flag in session->options */
    RELAXED_UNIQUE_CHECKS_F = (1U << 2),

    /** 
      Indicates that rows in this event are complete, that is contain
      values for all columns of the table.
     */
    COMPLETE_ROWS_F = (1U << 3)
  };

  typedef uint16_t flag_set;

  /* Special constants representing sets of flags */
  enum 
  {
      RLE_NO_FLAGS = 0U
  };

  virtual ~Rows_log_event();

  void set_flags(flag_set flags_arg) { m_flags |= flags_arg; }
  void clear_flags(flag_set flags_arg) { m_flags &= ~flags_arg; }
  flag_set get_flags(flag_set flags_arg) const { return m_flags & flags_arg; }

  virtual void pack_info(Protocol *protocol);

  int add_row_data(unsigned char *data, size_t length)
  {
    return do_add_row_data(data,length); 
  }

  /* Member functions to implement superclass interface */
  virtual int get_data_size();

  MY_BITMAP const *get_cols() const { return &m_cols; }
  size_t get_width() const          { return m_width; }
  ulong get_table_id() const        { return m_table_id; }

  virtual bool write_data_header(IO_CACHE *file);
  virtual bool write_data_body(IO_CACHE *file);
  virtual const char *get_db() { return m_table->s->db.str; }
  /*
    Check that malloc() succeeded in allocating memory for the rows
    buffer and the COLS vector. Checking that an Update_rows_log_event
    is valid is done in the Update_rows_log_event::is_valid()
    function.
  */
  virtual bool is_valid() const
  {
    return m_rows_buf && m_cols.bitmap;
  }

  uint32_t     m_row_count;         /* The number of rows added to the event */

protected:
  /* 
     The constructors are protected since you're supposed to inherit
     this class, not create instances of this class.
  */
  Rows_log_event(Session*, Table*, ulong table_id, 
		 MY_BITMAP const *cols, bool is_transactional);
  Rows_log_event(const char *row_data, uint32_t event_len, 
		 Log_event_type event_type,
		 const Format_description_log_event *description_event);

  virtual int do_add_row_data(unsigned char *data, size_t length);

  Table *m_table;		/* The table the rows belong to */
  ulong       m_table_id;	/* Table ID */
  MY_BITMAP   m_cols;		/* Bitmap denoting columns available */
  ulong       m_width;          /* The width of the columns bitmap */
  /*
    Bitmap for columns available in the after image, if present. These
    fields are only available for Update_rows events. Observe that the
    width of both the before image COLS vector and the after image
    COLS vector is the same: the number of columns of the table on the
    master.
  */
  MY_BITMAP   m_cols_ai;

  ulong       m_master_reclength; /* Length of record on master side */

  /* Bit buffers in the same memory as the class */
  uint32_t    m_bitbuf[128/(sizeof(uint32_t)*8)];
  uint32_t    m_bitbuf_ai[128/(sizeof(uint32_t)*8)];

  unsigned char    *m_rows_buf;		/* The rows in packed format */
  unsigned char    *m_rows_cur;		/* One-after the end of the data */
  unsigned char    *m_rows_end;		/* One-after the end of the allocated space */

  flag_set m_flags;		/* Flags for row-level events */

  /* helper functions */

  const unsigned char *m_curr_row;     /* Start of the row being processed */
  const unsigned char *m_curr_row_end; /* One-after the end of the current row */
  unsigned char    *m_key;      /* Buffer to keep key value during searches */

  int find_row(const Relay_log_info *const);
  int write_row(const Relay_log_info *const, const bool);

  // Unpack the current row into m_table->record[0]
  int unpack_current_row(const Relay_log_info *const rli,
                         MY_BITMAP const *cols);

private:

  virtual int do_apply_event(Relay_log_info const *rli);
  virtual int do_update_pos(Relay_log_info *rli);
  virtual enum_skip_reason do_shall_skip(Relay_log_info *rli);

  /*
    Primitive to prepare for a sequence of row executions.

    DESCRIPTION

      Before doing a sequence of do_prepare_row() and do_exec_row()
      calls, this member function should be called to prepare for the
      entire sequence. Typically, this member function will allocate
      space for any buffers that are needed for the two member
      functions mentioned above.

    RETURN VALUE

      The member function will return 0 if all went OK, or a non-zero
      error code otherwise.
  */
  virtual 
  int do_before_row_operations(const Slave_reporting_capability *const log) = 0;

  /*
    Primitive to clean up after a sequence of row executions.

    DESCRIPTION
    
      After doing a sequence of do_prepare_row() and do_exec_row(),
      this member function should be called to clean up and release
      any allocated buffers.
      
      The error argument, if non-zero, indicates an error which happened during
      row processing before this function was called. In this case, even if 
      function is successful, it should return the error code given in the argument.
  */
  virtual 
  int do_after_row_operations(const Slave_reporting_capability *const log,
                              int error) = 0;

  /*
    Primitive to do the actual execution necessary for a row.

    DESCRIPTION
      The member function will do the actual execution needed to handle a row.
      The row is located at m_curr_row. When the function returns, 
      m_curr_row_end should point at the next row (one byte after the end
      of the current row).    

    RETURN VALUE
      0 if execution succeeded, 1 if execution failed.
      
  */
  virtual int do_exec_row(const Relay_log_info *const rli) = 0;

  friend class Old_rows_log_event;
};

/**
  @class Write_rows_log_event

  Log row insertions and updates. The event contain several
  insert/update rows for a table. Note that each event contains only
  rows for one table.

  @section Write_rows_log_event_binary_format Binary Format
*/
class Write_rows_log_event : public Rows_log_event
{
public:
  enum 
  {
    /* Support interface to Session::binlog_prepare_pending_rows_event */
    TYPE_CODE = WRITE_ROWS_EVENT
  };

  Write_rows_log_event(Session*, Table*, ulong table_id, 
		       bool is_transactional);
  Write_rows_log_event(const char *buf, uint32_t event_len, 
                       const Format_description_log_event *description_event);
  static bool binlog_row_logging_function(Session *session, Table *table,
                                          bool is_transactional,
                                          const unsigned char *,
                                          const unsigned char *after_record)
  {
    return session->binlog_write_row(table, is_transactional, after_record);
  }

private:
  virtual Log_event_type get_type_code() { return (Log_event_type)TYPE_CODE; }

  virtual int do_before_row_operations(const Slave_reporting_capability *const);
  virtual int do_after_row_operations(const Slave_reporting_capability *const,int);
  virtual int do_exec_row(const Relay_log_info *const);
};


/**
  @class Update_rows_log_event

  Log row updates with a before image. The event contain several
  update rows for a table. Note that each event contains only rows for
  one table.

  Also note that the row data consists of pairs of row data: one row
  for the old data and one row for the new data.

  @section Update_rows_log_event_binary_format Binary Format
*/
class Update_rows_log_event : public Rows_log_event
{
public:
  enum 
  {
    /* Support interface to Session::binlog_prepare_pending_rows_event */
    TYPE_CODE = UPDATE_ROWS_EVENT
  };

  Update_rows_log_event(Session*, Table*, ulong table_id,
                        bool is_transactional);

  void init(MY_BITMAP const *cols);

  virtual ~Update_rows_log_event();

  Update_rows_log_event(const char *buf, uint32_t event_len, 
			const Format_description_log_event *description_event);

  static bool binlog_row_logging_function(Session *session, Table *table,
                                          bool is_transactional,
                                          const unsigned char *before_record,
                                          const unsigned char *after_record)
  {
    return session->binlog_update_row(table, is_transactional,
                                  before_record, after_record);
  }

  virtual bool is_valid() const
  {
    return Rows_log_event::is_valid() && m_cols_ai.bitmap;
  }

protected:
  virtual Log_event_type get_type_code() { return (Log_event_type)TYPE_CODE; }

  virtual int do_before_row_operations(const Slave_reporting_capability *const);
  virtual int do_after_row_operations(const Slave_reporting_capability *const,int);
  virtual int do_exec_row(const Relay_log_info *const);
};

/**
  @class Delete_rows_log_event

  Log row deletions. The event contain several delete rows for a
  table. Note that each event contains only rows for one table.

  RESPONSIBILITIES

    - Act as a container for rows that has been deleted on the master
      and should be deleted on the slave. 

  COLLABORATION

    Row_writer
      Create the event and add rows to the event.
    Row_reader
      Extract the rows from the event.

  @section Delete_rows_log_event_binary_format Binary Format
*/
class Delete_rows_log_event : public Rows_log_event
{
public:
  enum 
  {
    /* Support interface to Session::binlog_prepare_pending_rows_event */
    TYPE_CODE = DELETE_ROWS_EVENT
  };

  Delete_rows_log_event(Session*, Table*, ulong, 
			bool is_transactional);
  Delete_rows_log_event(const char *buf, uint32_t event_len, 
			const Format_description_log_event *description_event);
  static bool binlog_row_logging_function(Session *session, Table *table,
                                          bool is_transactional,
                                          const unsigned char *before_record,
                                          const unsigned char *)
  {
    return session->binlog_delete_row(table, is_transactional, before_record);
  }
  
protected:
  virtual Log_event_type get_type_code() { return (Log_event_type)TYPE_CODE; }

  virtual int do_before_row_operations(const Slave_reporting_capability *const);
  virtual int do_after_row_operations(const Slave_reporting_capability *const,int);
  virtual int do_exec_row(const Relay_log_info *const);
};


/**
  @class Incident_log_event

   Class representing an incident, an occurance out of the ordinary,
   that happened on the master.

   The event is used to inform the slave that something out of the
   ordinary happened on the master that might cause the database to be
   in an inconsistent state.

   <table id="IncidentFormat">
   <caption>Incident event format</caption>
   <tr>
     <th>Symbol</th>
     <th>Format</th>
     <th>Description</th>
   </tr>
   <tr>
     <td>INCIDENT</td>
     <td align="right">2</td>
     <td>Incident number as an unsigned integer</td>
   </tr>
   <tr>
     <td>MSGLEN</td>
     <td align="right">1</td>
     <td>Message length as an unsigned integer</td>
   </tr>
   <tr>
     <td>MESSAGE</td>
     <td align="right">MSGLEN</td>
     <td>The message, if present. Not null terminated.</td>
   </tr>
   </table>

  @section Delete_rows_log_event_binary_format Binary Format
*/
class Incident_log_event : public Log_event {
public:
  Incident_log_event(Session *session_arg, Incident incident)
    : Log_event(session_arg, 0, false), m_incident(incident)
  {
    m_message.str= NULL;                    /* Just as a precaution */
    m_message.length= 0;
    return;
  }

  Incident_log_event(Session *session_arg, Incident incident, LEX_STRING const msg)
    : Log_event(session_arg, 0, false), m_incident(incident)
  {
    m_message= msg;
    return;
  }

  void pack_info(Protocol*);

  Incident_log_event(const char *buf, uint32_t event_len,
                     const Format_description_log_event *descr_event);

  virtual ~Incident_log_event();

  virtual int do_apply_event(Relay_log_info const *rli);

  virtual bool write_data_header(IO_CACHE *file);
  virtual bool write_data_body(IO_CACHE *file);

  virtual Log_event_type get_type_code() { return INCIDENT_EVENT; }

  virtual bool is_valid() const { return 1; }
  virtual int get_data_size() {
    return INCIDENT_HEADER_LEN + 1 + m_message.length;
  }

private:
  const char *description() const;

  Incident m_incident;
  LEX_STRING m_message;
};

int append_query_string(const CHARSET_INFO * const csinfo,
                        String const *from, String *to);

static inline bool copy_event_cache_to_file_and_reinit(IO_CACHE *cache,
                                                       FILE *file)
{
  return         
    my_b_copy_to_file(cache, file) ||
    reinit_io_cache(cache, WRITE_CACHE, 0, false, true);
}

/*****************************************************************************

  Heartbeat Log Event class

  Replication event to ensure to slave that master is alive.
  The event is originated by master's dump thread and sent straight to
  slave without being logged. Slave itself does not store it in relay log
  but rather uses a data for immediate checks and throws away the event.

  Two members of the class log_ident and Log_event::log_pos comprise 
  @see the event_coordinates instance. The coordinates that a heartbeat
  instance carries correspond to the last event master has sent from
  its binlog.

 ****************************************************************************/
class Heartbeat_log_event: public Log_event
{
public:
  Heartbeat_log_event(const char* buf, uint32_t event_len,
                      const Format_description_log_event* description_event);
  Log_event_type get_type_code() { return HEARTBEAT_LOG_EVENT; }
  bool is_valid() const
    {
      return (log_ident != NULL &&
              log_pos >= BIN_LOG_HEADER_SIZE);
    }
  const char * get_log_ident() { return log_ident; }
  uint32_t get_ident_len() { return ident_len; }
  
private:
  const char* log_ident;
  uint32_t ident_len;
};

/**
  @} (end of group Replication)
*/

#endif /* DRIZZLED_LOG_EVENT_H */