diff options
Diffstat (limited to 'sql/log.h')
| -rw-r--r-- | sql/log.h | 36 |
1 files changed, 35 insertions, 1 deletions
diff --git a/sql/log.h b/sql/log.h index 503e94df981..6437046b17b 100644 --- a/sql/log.h +++ b/sql/log.h @@ -403,7 +403,41 @@ public: /* This is relay log */ bool is_relay_log; - + uint8 checksum_alg_reset; // to contain a new value when binlog is rotated + /* + Holds the last seen in Relay-Log FD's checksum alg value. + The initial value comes from the slave's local FD that heads + the very first Relay-Log file. In the following the value may change + with each received master's FD_m. + Besides to be used in verification events that IO thread receives + (except the 1st fake Rotate, see @c Master_info:: checksum_alg_before_fd), + the value specifies if/how to compute checksum for slave's local events + and the first fake Rotate (R_f^1) coming from the master. + R_f^1 needs logging checksum-compatibly with the RL's heading FD_s. + + Legends for the checksum related comments: + + FD - Format-Description event, + R - Rotate event + R_f - the fake Rotate event + E - an arbirary event + + The underscore indexes for any event + `_s' indicates the event is generated by Slave + `_m' - by Master + + Two special underscore indexes of FD: + FD_q - Format Description event for queuing (relay-logging) + FD_e - Format Description event for executing (relay-logging) + + Upper indexes: + E^n - n:th event is a sequence + + RL - Relay Log + (A) - checksum algorithm descriptor value + FD.(A) - the value of (A) in FD + */ + uint8 relay_log_checksum_alg; /* These describe the log's format. This is used only for relay logs. _for_exec is used by the SQL thread, _for_queue by the I/O thread. It's |