diff options
Diffstat (limited to 'sql/log_event.h')
| -rw-r--r-- | sql/log_event.h | 119 |
1 files changed, 108 insertions, 11 deletions
diff --git a/sql/log_event.h b/sql/log_event.h index 1d2fc741fa8..bd5e1a82be4 100644 --- a/sql/log_event.h +++ b/sql/log_event.h @@ -34,15 +34,21 @@ #define LOG_READ_TOO_LARGE -7 #define LOG_EVENT_OFFSET 4 + #define BINLOG_VERSION 3 /* We could have used SERVER_VERSION_LENGTH, but this introduces an obscure dependency - if somebody decided to change SERVER_VERSION_LENGTH - this would have broke the replication protocol + this would have broken 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). +*/ + #define DUMPFILE_FLAG 0x1 #define OPT_ENCLOSED_FLAG 0x2 #define REPLACE_FLAG 0x4 @@ -121,11 +127,17 @@ struct sql_ex_info See the #defines below for the format specifics. + The events which really update data are Query_log_event and + Load_log_event/Create_file_log_event/Execute_load_log_event (these 3 act + together to replicate LOAD DATA INFILE, with the help of + Append_block_log_event which prepares temporary files to load into the table). + ****************************************************************************/ +#define LOG_EVENT_HEADER_LEN 19 /* the fixed header length */ +#define OLD_HEADER_LEN 13 /* the fixed header length in 3.23 */ + /* event-specific post-header sizes */ -#define LOG_EVENT_HEADER_LEN 19 -#define OLD_HEADER_LEN 13 #define QUERY_HEADER_LEN (4 + 4 + 1 + 2) #define LOAD_HEADER_LEN (4 + 4 + 4 + 1 +1 + 4) #define START_HEADER_LEN (2 + ST_SERVER_VER_LEN + 4) @@ -135,7 +147,10 @@ struct sql_ex_info #define EXEC_LOAD_HEADER_LEN 4 #define DELETE_FILE_HEADER_LEN 4 -/* event header offsets */ +/* + Event header offsets; + these point to places inside the fixed header. +*/ #define EVENT_TYPE_OFFSET 4 #define SERVER_ID_OFFSET 5 @@ -149,7 +164,7 @@ struct sql_ex_info #define ST_SERVER_VER_OFFSET 2 #define ST_CREATED_OFFSET (ST_SERVER_VER_OFFSET + ST_SERVER_VER_LEN) -/* slave event post-header */ +/* slave event post-header (this event is never written) */ #define SL_MASTER_PORT_OFFSET 8 #define SL_MASTER_POS_OFFSET 0 @@ -197,14 +212,20 @@ struct sql_ex_info #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 #define QUERY_EVENT_OVERHEAD (LOG_EVENT_HEADER_LEN+QUERY_HEADER_LEN) @@ -217,13 +238,31 @@ struct sql_ex_info #define EXEC_LOAD_EVENT_OVERHEAD (LOG_EVENT_HEADER_LEN+EXEC_LOAD_HEADER_LEN) #define APPEND_BLOCK_EVENT_OVERHEAD (LOG_EVENT_HEADER_LEN+APPEND_BLOCK_HEADER_LEN) - +/* 4 bytes which all binlogs should begin with */ #define BINLOG_MAGIC "\xfe\x62\x69\x6e" +/* + The 2 flags below were useless : + - the first one was never set + - the second one was set in all Rotate events on the master, but not used for + anything useful. + So they are now removed and their place may later be reused for other + flags. Then one must remember that Rotate events in 4.x have + LOG_EVENT_FORCED_ROTATE_F set, so one should not rely on the value of the + replacing flag when reading a Rotate event. + I keep the defines here just to remember what they were. +*/ +#ifdef TO_BE_REMOVED #define LOG_EVENT_TIME_F 0x1 -#define LOG_EVENT_FORCED_ROTATE_F 0x2 -#define LOG_EVENT_THREAD_SPECIFIC_F 0x4 /* query depends on thread - (for example: TEMPORARY TABLE) */ +#define LOG_EVENT_FORCED_ROTATE_F 0x2 +#endif +/* + 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 enum Log_event_type { @@ -258,30 +297,81 @@ struct st_relay_log_info; class Log_event { public: + /* + 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. + */ my_off_t log_pos; - char *temp_buf; + /* + 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; + /* + The master's server id (is preserved in the relay log; used to prevent from + infinite loops in circular replication). + */ uint32 server_id; uint cached_event_len; + + /* + Some 16 flags. Only one is really used now; look above for + LOG_EVENT_TIME_F, LOG_EVENT_FORCED_ROTATE_F, LOG_EVENT_THREAD_SPECIFIC_F + for notes. + */ uint16 flags; + bool cache_stmt; #ifndef MYSQL_CLIENT THD* thd; Log_event(THD* thd_arg, uint16 flags_arg, bool cache_stmt); Log_event(); + /* + 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 static Log_event* read_log_event(IO_CACHE* file, pthread_mutex_t* log_lock, bool old_format); static int read_log_event(IO_CACHE* file, String* packet, pthread_mutex_t* log_lock); + /* set_log_pos() is used to fill log_pos with tell(log). */ void set_log_pos(MYSQL_LOG* log); + /* + 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); #ifdef HAVE_REPLICATION 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); + /* + The SQL slave thread calls exec_event() to execute the event; this is where + the slave's data is modified. + */ virtual int exec_event(struct st_relay_log_info* rli); #endif /* HAVE_REPLICATION */ virtual const char* get_db() @@ -291,6 +381,7 @@ public: #else // avoid having to link mysqlbinlog against libpthread static Log_event* read_log_event(IO_CACHE* file, bool old_format); + /* print*() functions are used by mysqlbinlog */ virtual void print(FILE* file, bool short_form = 0, char* last_db = 0) = 0; void print_timestamp(FILE* file, time_t *ts = 0); void print_header(FILE* file); @@ -336,6 +427,7 @@ public: } static Log_event* read_log_event(const char* buf, int event_len, const char **error, bool old_format); + /* returns the human readable name of the event's type */ const char* get_type_str(); }; @@ -403,6 +495,8 @@ public: /***************************************************************************** Slave Log Event class + Note that this class is currently not used at all; no code writes a + Slave_log_event (though some code in repl_failsafe.cc reads Slave_log_event). ****************************************************************************/ class Slave_log_event: public Log_event @@ -593,7 +687,7 @@ public: Rand Log Event class - Logs random seed used by the next RAND() + Logs random seed used by the next RAND(), and by PASSWORD() in 4.1. ****************************************************************************/ class Rand_log_event: public Log_event @@ -626,6 +720,9 @@ class Rand_log_event: public Log_event User var Log Event class + 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. + ****************************************************************************/ class User_var_log_event: public Log_event { |