(WL#794). This can be of interest in some recovery-from-backup scenarios, and also when you have
two databases in one mysqld, having a certain similarity and you want one db to be updated when the other is
(some sort of trigger).
Plus small fix for BUG#3568 "MySQL server crashes when built --with-debug and CHANGE MASTER +MASTER_POS_WAIT"
too big by 6 bytes. So I add code to substract 6 bytes if the master is 3.23.
This is not perfect (because it won't work if the slave I/O thread has not
noticed yet that the master is 3.23), but as long as the slave I/O thread
starts Exec_master_log_pos will be ok.
It must be merged to 4.1 but not to 5.0 (or it can be, because of #if MYSQL_VERSION_ID),
because 5.0 already works if the master is 3.23 (and in a more natural way:
in 5.0 we store the end_log_pos in the binlog and relay log).
I had to move functions from slave.h to slave.cc to satisfy gcc.
re-using unused LOCK_active_mi to serialize all administrative
commands related to replication:
START SLAVE, STOP SLAVE, RESET SLAVE, CHANGE MASTER, init_slave()
(replication autostart at server startup), end_slave() (replication
autostop at server shutdown), LOAD DATA FROM MASTER.
This protects us against a handful of deadlocks (like BUG#2921
when two START SLAVE, but when two STOP SLAVE too).
Removing unused variables.
ChangeSet 1.1620.12.1 and ChangeSet 1.1625.2.1
from 4.1. This makes the slave I/O thread flush the relay log
after every event, which provides additional safety in case
of brutal crash (reduces chances to lose a part of the relay log).
- the one about BUG#2921
- the one about relay log flushing
Both will be rewritten in a next changeset
(this one will not be pushed before the next changeset).
"(binlog, position) stored by InnoDB for a replication slave can be wrong".
This code contains conditional #if to distinguish between versions;
it should be merged into 4.1 and 5.0.
Now the I/O thread (in flush_master_info()) flushes the relay log to disk
after reading every event. Slower but provides additionnal safety in case
of brutal crash.
I had to make the flush optional (i.e. add a if(some_bool_argument) in the function)
because sometimes flush_master_info() is called when there is no usable
relay log (the relay log's IO_CACHE is not initialized so can't be flushed).
- when we don't have in_addr_t, use uint32.
- a forgotten initialization of slave_proxy_id in sql/log_event.cc (was not really "forgot", was
"we needn't init it there", but there was one case where we needed...).
- made slave_proxy_id always meaningful in THD and Log_event, so we can
rely more on it (no need to test if it's meaningful). THD::slave_proxy_id
is equal to THD::thread_id except for the slave SQL thread.
- clean up the slave's temporary table (i.e. free their memory) when slave
server shuts down.
"Add a column "Timestamp_of_last_master_event_executed" in SHOW SLAVE STATUS".
Finally this is adding
- Slave_IO_State (a copy of the State column of SHOW PROCESSLIST for the I/O thread,
so that the users, most of the time, has enough info with only SHOW SLAVE STATUS).
- Seconds_behind_master. When the slave connects to the master it does SELECT UNIX_TIMESTAMP()
on the master, computes the absolute difference between the master's and the slave's clock.
It records the timestamp of the last event executed by the SQL thread, and does a
small computation to find the number of seconds by which the slave is late.
Now LOAD DATA FROM MASTER does not drop the database, instead it only tries to
create it, and drops/creates table-by-table.
* replicate_wild_ignore_table='db1.%' is now considered as "ignore the 'db1'
database as a whole", as it already works for CREATE DATABASE and DROP DATABASE.
Added proper options to CHANGE MASTER TO, new fields to SHOW SLAVE STATUS,
Honoring this parameters during connection to master.
Introduced new format of master.info file
- Bug #985: "Between RESET SLAVE and START SLAVE, SHOW SLAVE STATUS is wrong."
Now RESET SLAVE puts correct info in mi->host etc. A new test rpl_reset_slave
for that.
- Bug #986: "CHANGE MASTER & START SLAVE do not reset error columns in SHOW
SLAVE STATUS". Now these reset the errors.
I extended the task to cleaning error messages, making them look nicer,
and making the output of SHOW SLAVE STATUS (column Last_error) be as complete
as what's printed on the .err file;
previously we would have, for a failure of a replicated LOAD DATA INFILE:
- in the .err, 2 lines:
"duplicate entry 2708 for key 1"
"failed loading SQL_LOAD-5-2-2.info"
- and in SHOW SLAVE STATUS, only:
"failed loading SQL_LOAD-5-2-2.info".
Now SHOW SLAVE STATUS will contain the concatenation of the 2 messages.
and other replicate-*-table options in SHOW SLAVE STATUS.
Seems like it had not been done, so I push it now:
there's 4 new columns to SHOW SLAVE STATUS.
Added MAX_PASSWORD_LENGTH. This increased master-slave passwords to 32 bytes (Bug #766)
Fixed server crash on purge master logs or show master logs when binlog is off. (Bug #733)
- Comments for future devs.
- Start_log_event::exec_event() : when we hit it, do a rollback.
- We don't need LOG_EVENT_FORCED_ROTATE_F.
- Stop_log_event::exec_event() : when we hit it, we needn't clean anything.
- Removed LOG_EVENT_TIME_F and LOG_EVENT_FORCED_ROTATE_F.
- We don't need Stop events in the relay log.
- Now filtering of server id is done in the I/O thread first.
we now make a distinction between if the master is < 3.23.57, 3.23 && >=57, and 4.x
(before the 2 3.23 were one). This is because in 3.23.57 we have a way to distinguish between
a Start_log_event written at server startup and one written at FLUSH LOGS, so we
have a way to know if the slave must drop old temp tables or not.
Change: mi->old_format was bool, now it's enum (to handle 3 cases). However, functions
which had 'bool old_format' as an argument have their prototypes unchanged, because
the old old_format == 0 now corresponds to the enum value BINLOG_FORMAT_CURRENT which
is equal to 0, so boolean tests are left untouched. The only case were we use mi->old_format
as an enum instead of casting it implicitly to a bool, is in Start_log_event::exec_event,
where we want to distinguish between the 3 possible enum values.
