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Log_event Class Reference

#include <log_event.h>

Inheritance diagram for Log_event:
Append_block_log_event Delete_file_log_event Execute_load_log_event Gtid_log_event Ignorable_log_event Incident_log_event Intvar_log_event Load_log_event Old_rows_log_event Previous_gtids_log_event Query_log_event Rand_log_event Rotate_log_event Rows_log_event Start_log_event_v3 Stop_log_event Table_map_log_event User_var_log_event Xid_log_event

List of all members.

Public Types

typedef unsigned char Byte

Public Member Functions

 Log_event (enum_event_cache_type cache_type_arg=EVENT_INVALID_CACHE, enum_event_logging_type logging_type_arg=EVENT_INVALID_LOGGING)
virtual void print (FILE *file, PRINT_EVENT_INFO *print_event_info)=0
void print_timestamp (IO_CACHE *file, time_t *ts)
void print_header (IO_CACHE *file, PRINT_EVENT_INFO *print_event_info, bool is_more)
void print_base64 (IO_CACHE *file, PRINT_EVENT_INFO *print_event_info, bool is_more)
bool wrapper_my_b_safe_write (IO_CACHE *file, const uchar *buf, ulong data_length)
virtual Log_event_type get_type_code ()=0
virtual bool is_valid () const =0
void set_artificial_event ()
void set_relay_log_event ()
bool is_artificial_event () const
bool is_relay_log_event () const
bool is_ignorable_event () const
bool is_no_filter_event () const
bool is_using_trans_cache () const
bool is_using_stmt_cache () const
bool is_using_immediate_logging () const
 Log_event (const char *buf, const Format_description_log_event *description_event)
void register_temp_buf (char *buf)
void free_temp_buf ()
virtual int get_data_size ()
const char * get_type_str ()

Static Public Member Functions

static Log_eventread_log_event (IO_CACHE *file, const Format_description_log_event *description_event, my_bool crc_check)
static void * operator new (size_t size)
static void operator delete (void *ptr, size_t)
static void * operator new (size_t, void *ptr)
static void operator delete (void *, void *)
static Log_eventread_log_event (const char *buf, uint event_len, const char **error, const Format_description_log_event *description_event, my_bool crc_check)
static const char * get_type_str (Log_event_type type)

Public Attributes

my_off_t log_pos
char * temp_buf
struct timeval when
ulong exec_time
ulong data_written
uint32 server_id
uint32 unmasked_server_id
uint16 flags
ulong slave_exec_mode
enum_event_cache_type event_cache_type
enum_event_logging_type event_logging_type
ha_checksum crc
ulong mts_group_idx
ulonglong future_event_relay_log_pos
uint8 checksum_alg

Protected Types

enum  enum_event_cache_type {

Detailed Description

This is the abstract base class for binary log events.

Binary Format

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

The Common-Header, documented in the table 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.

Name Format


timestamp 4 byte unsigned integer

The time when the query started, in seconds since 1970.

type 1 byte enumeration

See enum Log_event_type.

server_id 4 byte unsigned integer

Server ID of the server that created the event.

total_size 4 byte unsigned integer

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.

master_position 4 byte unsigned integer

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.

flags 2 byte bitfield See Log_event::flags.

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

Format of Atomic Primitives

Format of Packed Integer
First byte



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


Two more bytes are used. The number is in the range 251-0xffff.


Three more bytes are used. The number is in the range 0xffff-0xffffff.


Eight more bytes are used. The number is in the range 0xffffff-0xffffffffffffffff.

Member Enumeration Documentation

Enumeration of what kinds of skipping (and non-skipping) that can occur when the slave executes an event.

See also:

Don't skip event.


Skip event by ignoring it.

This means that the slave skip counter will not be changed.


Skip event and decrease skip counter.

Constructor & Destructor Documentation

Log_event::Log_event ( enum_event_cache_type  cache_type_arg = EVENT_INVALID_CACHE,
enum_event_logging_type  logging_type_arg = EVENT_INVALID_LOGGING 
) [inline]

This minimal constructor is for when you are not even sure that there is a valid THD. For example in the server when we are shutting down or flushing logs after receiving a SIGHUP (then we must write a Rotate to the binlog but we have no THD, so we need this minimal constructor).

Member Function Documentation

const char * Log_event::get_type_str ( Log_event_type  type) [static]

Returns the human readable name of the given event type.

Prints a "session_var=value" string. Used by mysqlbinlog to print some SET commands just before it prints a query.

returns the human readable name of the event's type
const char * Log_event::get_type_str ( )

Returns the human readable name of this event's type.

Log_event * Log_event::read_log_event ( const char *  buf,
uint  event_len,
const char **  error,
const Format_description_log_event description_event,
my_bool  crc_check 
) [static]

Binlog format tolerance is in (buf, event_len, description_event) constructors.

Member Data Documentation

ha_checksum Log_event::crc

Placeholder for event checksum while writing to binlog.

enum_event_cache_type Log_event::event_cache_type

Defines the type of the cache, if any, where the event will be stored before being flushed to disk.

enum_event_logging_type Log_event::event_logging_type

Defines when information, i.e. event or cache, will be flushed to disk.

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.

Reimplemented in Rotate_log_event, and User_var_log_event.

A copy of the main rli value stored into event to pass to MTS worker rli

Index in rli->gaq array to indicate a group that this event is purging. The index is set by Coordinator to a group terminator event is checked by Worker at the event execution. The indexed data represent the Worker progress status.

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

MTS: associating the event with either an assigned Worker or Coordinator. Additionally the member serves to tag deferred (IRU) events to avoid the event regular time destruction.

The documentation for this class was generated from the following files:
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