MySQL  8.0.17
Source Code Documentation
User_var_log_event Class Reference

Every time a query uses the value of a user variable, a User_var_log_event is written before the Query_log_event, to set the user variable. More...

#include <log_event.h>

Inheritance diagram for User_var_log_event:
binary_log::User_var_event Log_event binary_log::Binary_log_event

Public Member Functions

 User_var_log_event (THD *thd_arg, const char *name_arg, uint name_len_arg, char *val_arg, ulong val_len_arg, Item_result type_arg, uint charset_number_arg, uchar flags_arg, enum_event_cache_type cache_type_arg, enum_event_logging_type logging_type_arg)
 
int pack_info (Protocol *protocol) override
 Stores a string representation of this event in the Protocol. More...
 
 User_var_log_event (const char *buf, const Format_description_event *description_event)
 
 ~User_var_log_event () override
 
bool write (Basic_ostream *ostream) override
 
bool is_deferred ()
 
void set_deferred (query_id_t qid)
 
bool is_sbr_logging_format () const override
 Return true if the event has to be logged using SBR for DMLs. More...
 
- Public Member Functions inherited from binary_log::User_var_event
 User_var_event (const char *name_arg, unsigned int name_len_arg, char *val_arg, unsigned long val_len_arg, Value_type type_arg, unsigned int charset_number_arg, unsigned char flags_arg)
 This constructor will initialize the instance variables and the type_code, it will be used only by the server code. More...
 
 User_var_event (const char *buf, const Format_description_event *fde)
 The constructor receives a buffer and instantiates a User_var_event filled in with the data from the buffer Written every time a statement uses a user variable, precedes other events for the statement. More...
 
virtual ~User_var_event ()
 
- Public Member Functions inherited from binary_log::Binary_log_event
virtual ~Binary_log_event ()=0
 
 Binary_log_event (const Binary_log_event &)=default
 
 Binary_log_event (Binary_log_event &&)=default
 
Binary_log_eventoperator= (const Binary_log_event &)=default
 
Binary_log_eventoperator= (Binary_log_event &&)=default
 
enum Log_event_type get_event_type () const
 Helper method. More...
 
const Log_event_headerheader () const
 Return a const pointer to the header of the log event. More...
 
Log_event_headerheader ()
 Return a non-const pointer to the header of the log event. More...
 
const Log_event_footerfooter () const
 Return a const pointer to the footer of the log event. More...
 
Log_event_footerfooter ()
 Return a non-const pointer to the footer of the log event. More...
 
Event_readerreader ()
 Returns a reference to the event Event_reader object. More...
 
- Public Member Functions inherited from Log_event
 Log_event (Log_event_header *header, Log_event_footer *footer, enum_event_cache_type cache_type_arg, enum_event_logging_type logging_type_arg)
 This minimal constructor is for when you are not even sure that there is a valid THD. More...
 
 Log_event (THD *thd_arg, uint16 flags_arg, enum_event_cache_type cache_type_arg, enum_event_logging_type logging_type_arg, Log_event_header *header, Log_event_footer *footer)
 
int net_send (Protocol *protocol, const char *log_name, my_off_t pos)
 Only called by SHOW BINLOG EVENTS. More...
 
virtual const char * get_db ()
 
void * operator new (size_t size)
 
bool wrapper_my_b_safe_write (Basic_ostream *ostream, const uchar *buf, size_t data_length)
 Write the given buffer to the given output stream, updating the checksum if checksums are enabled. More...
 
time_t get_time ()
 Prints a "session_var=value" string. More...
 
virtual bool write_data_header (Basic_ostream *)
 
virtual bool write_data_body (Basic_ostream *)
 
Log_event_type get_type_code () const
 
virtual bool is_rbr_logging_format () const
 Return true if the event has to be logged using RBR for DMLs. More...
 
bool is_valid ()
 
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 (Log_event_header *header, Log_event_footer *footer)
 
virtual ~Log_event ()
 
void register_temp_buf (char *buf, bool free_in_destructor=true)
 
void free_temp_buf ()
 
virtual size_t get_data_size ()
 
const char * get_type_str () const
 Returns the human readable name of this event's type. More...
 
bool is_mts_sequential_exec ()
 Is called from get_mts_execution_mode() to. More...
 
virtual uint8 get_mts_dbs (Mts_db_names *arg, Rpl_filter *rpl_filter)
 The method fills in pointers to event's database name c-strings to a supplied array. More...
 
bool contains_partition_info (bool)
 
virtual uint8 mts_number_dbs ()
 
bool is_mts_group_isolated ()
 
virtual bool starts_group () const
 Events of a certain type can start or end a group of events treated transactionally wrt binlog. More...
 
virtual bool ends_group () const
 
int apply_event (Relay_log_info *rli)
 Apply the event to the database. More...
 
int apply_gtid_event (Relay_log_info *rli)
 Apply the GTID event in curr_group_data to the database. More...
 
int update_pos (Relay_log_info *rli)
 Update the relay log position. More...
 
enum_skip_reason shall_skip (Relay_log_info *rli)
 Decide if the event shall be skipped, and the reason for skipping it. More...
 
virtual int do_apply_event_worker (Slave_worker *w)
 

Public Attributes

bool deferred
 
query_id_t query_id
 
- Public Attributes inherited from binary_log::User_var_event
const char * name
 
unsigned int name_len
 
char * val
 
uint32_t val_len
 
Value_type type
 
unsigned int charset_number
 
bool is_null
 
unsigned char flags
 
- Public Attributes inherited from Log_event
char * temp_buf
 
bool m_free_temp_buf_in_destructor
 
ulong exec_time
 
uint32 server_id
 
ulong rbr_exec_mode
 A storage to cache the global system variable's value. More...
 
enum_event_cache_type event_cache_type
 Defines the type of the cache, if any, where the event will be stored before being flushed to disk. More...
 
enum_event_logging_type event_logging_type
 Defines when information, i.e. More...
 
ha_checksum crc
 Placeholder for event checksum while writing to binlog. More...
 
ulong mts_group_idx
 Index in rli->gaq array to indicate a group that this event is purging. More...
 
binary_log::Log_event_headercommon_header
 
The Log_event_header class contains the variable present in the common header More...
 
binary_log::Log_event_footercommon_footer
 
The Log_event_footer class contains the variable present in the common footer. More...
 
Relay_log_infoworker
 MTS: associating the event with either an assigned Worker or Coordinator. More...
 
ulonglong future_event_relay_log_pos
 A copy of the main rli value stored into event to pass to MTS worker rli. More...
 
THDthd
 
db_worker_hash_entrymts_assigned_partitions [MAX_DBS_IN_EVENT_MTS]
 Partition info associate with event to deliver to MTS event applier. More...
 

Private Member Functions

virtual int do_apply_event (Relay_log_info const *rli) override
 Primitive to apply an event to the database. More...
 
virtual int do_update_pos (Relay_log_info *rli) override
 Advance relay log coordinates. More...
 
virtual enum_skip_reason do_shall_skip (Relay_log_info *rli) override
 Decide if this event shall be skipped or not and the reason for skipping it. More...
 

Additional Inherited Members

- Public Types inherited from binary_log::User_var_event
enum  { UNDEF_F, UNSIGNED_F }
 
enum  User_var_event_data {
  UV_VAL_LEN_SIZE = 4, UV_VAL_IS_NULL = 1, UV_VAL_TYPE_SIZE = 1, UV_NAME_LEN_SIZE = 4,
  UV_CHARSET_NUMBER_SIZE = 4
}
 
using Value_type = Item_result
 
- Public Types inherited from binary_log::Binary_log_event
enum  enum_post_header_length {
  QUERY_HEADER_MINIMAL_LEN = (4 + 4 + 1 + 2), QUERY_HEADER_LEN = (QUERY_HEADER_MINIMAL_LEN + 2), STOP_HEADER_LEN = 0, START_V3_HEADER_LEN = (2 + ST_SERVER_VER_LEN + 4),
  ROTATE_HEADER_LEN = 8, INTVAR_HEADER_LEN = 0, APPEND_BLOCK_HEADER_LEN = 4, DELETE_FILE_HEADER_LEN = 4,
  RAND_HEADER_LEN = 0, USER_VAR_HEADER_LEN = 0, FORMAT_DESCRIPTION_HEADER_LEN = (START_V3_HEADER_LEN + 1 + LOG_EVENT_TYPES), XID_HEADER_LEN = 0,
  BEGIN_LOAD_QUERY_HEADER_LEN = APPEND_BLOCK_HEADER_LEN, ROWS_HEADER_LEN_V1 = 8, TABLE_MAP_HEADER_LEN = 8, EXECUTE_LOAD_QUERY_EXTRA_HEADER_LEN = (4 + 4 + 4 + 1),
  EXECUTE_LOAD_QUERY_HEADER_LEN, INCIDENT_HEADER_LEN = 2, HEARTBEAT_HEADER_LEN = 0, IGNORABLE_HEADER_LEN = 0,
  ROWS_HEADER_LEN_V2 = 10, TRANSACTION_CONTEXT_HEADER_LEN = 18, VIEW_CHANGE_HEADER_LEN = 52, XA_PREPARE_HEADER_LEN = 0
}
 The lengths for the fixed data part of each event. More...
 
- Public Types inherited from Log_event
enum  enum_skip_reason { EVENT_SKIP_NOT, EVENT_SKIP_IGNORE, EVENT_SKIP_COUNT }
 Enumeration of what kinds of skipping (and non-skipping) that can occur when the slave executes an event. More...
 
- Static Public Member Functions inherited from Log_event
static void init_show_field_list (List< Item > *field_list)
 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. More...
 
static void operator delete (void *ptr, size_t)
 
static void * operator new (size_t, void *ptr)
 
static void operator delete (void *, void *)
 
static const char * get_type_str (Log_event_type type)
 Returns the human readable name of the given event type. More...
 
- Static Public Attributes inherited from binary_log::Binary_log_event
static const int LOG_EVENT_TYPES = (ENUM_END_EVENT - 1)
 
- Protected Types inherited from Log_event
enum  enum_event_cache_type {
  EVENT_INVALID_CACHE = 0, EVENT_STMT_CACHE, EVENT_TRANSACTIONAL_CACHE, EVENT_NO_CACHE,
  EVENT_CACHE_COUNT
}
 
enum  enum_event_logging_type { EVENT_INVALID_LOGGING = 0, EVENT_NORMAL_LOGGING, EVENT_IMMEDIATE_LOGGING, EVENT_CACHE_LOGGING_COUNT }
 
- Protected Member Functions inherited from binary_log::Binary_log_event
 Binary_log_event (Log_event_type type_code)
 This constructor is used to initialize the type_code of header object m_header. More...
 
 Binary_log_event (const char **buf, const Format_description_event *fde)
 This constructor will create a new object of Log_event_header and initialize the variable m_header, which in turn will be used to initialize Log_event's member common_header. More...
 
- Protected Member Functions inherited from Log_event
uint32 write_header_to_memory (uchar *buf)
 Writes the common header of this event to the given memory buffer. More...
 
bool write_header (Basic_ostream *ostream, size_t data_length)
 Writes the common-header of this event to the given output stream and updates the checksum. More...
 
bool write_footer (Basic_ostream *ostream)
 
bool need_checksum ()
 A decider of whether to trigger checksum computation or not. More...
 
enum_skip_reason continue_group (Relay_log_info *rli)
 Helper function to ignore an event w.r.t. More...
 

Detailed Description

Every time a query uses the value of a user variable, a User_var_log_event is written before the Query_log_event, to set the user variable.

Constructor & Destructor Documentation

◆ User_var_log_event() [1/2]

User_var_log_event::User_var_log_event ( THD thd_arg,
const char *  name_arg,
uint  name_len_arg,
char *  val_arg,
ulong  val_len_arg,
Item_result  type_arg,
uint  charset_number_arg,
uchar  flags_arg,
enum_event_cache_type  cache_type_arg,
enum_event_logging_type  logging_type_arg 
)
inline

◆ User_var_log_event() [2/2]

User_var_log_event::User_var_log_event ( const char *  buf,
const Format_description_event description_event 
)

◆ ~User_var_log_event()

User_var_log_event::~User_var_log_event ( )
inlineoverride

Member Function Documentation

◆ do_apply_event()

int User_var_log_event::do_apply_event ( Relay_log_info const *  rli)
overrideprivatevirtual

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 also
Format_description_log_event::do_apply_event()
Parameters
rliPointer to relay log info structure
Return values
0Event applied successfully
errnoError code if event application failed

Reimplemented from Log_event.

◆ do_shall_skip()

Log_event::enum_skip_reason User_var_log_event::do_shall_skip ( Relay_log_info rli)
overrideprivatevirtual

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 rli->replicate_same_server_id is true, or
  • if rli->slave_skip_counter is greater than zero.
See also
do_apply_event
do_update_pos
Return values
Log_event::EVENT_SKIP_NOTThe event shall not be skipped and should be applied.
Log_event::EVENT_SKIP_IGNOREThe 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.
Log_event::EVENT_SKIP_COUNTThe event shall be skipped because the slave skip counter was non-zero. The caller shall decrease the counter by one.

Reimplemented from Log_event.

◆ do_update_pos()

int User_var_log_event::do_update_pos ( Relay_log_info rli)
overrideprivatevirtual

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 if the event is last in a group
Parameters
rliPointer to relay log info structure
Return values
0Coordinates changed successfully
errnoError code if advancing failed (usually just 1). Observe that handler errors are returned by the do_apply_event() function, and not by this one.

Reimplemented from Log_event.

◆ is_deferred()

bool User_var_log_event::is_deferred ( )
inline

◆ is_sbr_logging_format()

bool User_var_log_event::is_sbr_logging_format ( ) const
inlineoverridevirtual

Return true if the event has to be logged using SBR for DMLs.

Reimplemented from Log_event.

◆ pack_info()

int User_var_log_event::pack_info ( Protocol protocol)
overridevirtual

Stores a string representation of this event in the Protocol.

This is used by SHOW BINLOG EVENTS.

Return values
0success
nonzeroerror

Reimplemented from Log_event.

◆ set_deferred()

void User_var_log_event::set_deferred ( query_id_t  qid)
inline

◆ write()

bool User_var_log_event::write ( Basic_ostream ostream)
overridevirtual

Reimplemented from Log_event.

Member Data Documentation

◆ deferred

bool User_var_log_event::deferred

◆ query_id

query_id_t User_var_log_event::query_id

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