This is the main commit for Worklog tasks:
* A more dynamic binlog format which allows small changes (1064)
* Log session variables in Query_log_event (1063)
Below 5.0 means 5.0.0.
MySQL 5.0 is able to replicate FOREIGN_KEY_CHECKS, UNIQUE_KEY_CHECKS (for speed),
SQL_AUTO_IS_NULL, SQL_MODE. Not charsets (WL#1062), not some vars (I can only think
of SQL_SELECT_LIMIT, which deserves a special treatment). Note that this
works for queries, except LOAD DATA INFILE (for this it would have to wait
for Dmitri's push of WL#874, which in turns waits for the present push, so...
the deadlock must be broken!). Note that when Dmitri pushes WL#874 in 5.0.1,
5.0.0 won't be able to replicate a LOAD DATA INFILE from 5.0.1.
Apart from that, the new binlog format is designed so that it can tolerate
a little variation in the events (so that a 5.0.0 slave could replicate a
5.0.1 master, except for LOAD DATA INFILE unfortunately); that is, when I
later add replication of charsets it should break nothing. And when I later
add a UID to every event, it should break nothing.
The main change brought by this patch is a new type of event, Format_description_log_event,
which describes some lengthes in other event types. This event is needed for
the master/slave/mysqlbinlog to understand a 5.0 log. Thanks to this event,
we can later add more bytes to the header of every event without breaking compatibility.
Inside Query_log_event, we have some additional dynamic format, as every Query_log_event
can have a different number of status variables, stored as pairs (code, value); that's
how SQL_MODE and session variables and catalog are stored. Like this, we can later
add count of affected rows, charsets... and we can have options --don't-log-count-affected-rows
if we want.
MySQL 5.0 is able to run on 4.x relay logs, 4.x binlogs.
Upgrading a 4.x master to 5.0 is ok (no need to delete binlogs),
upgrading a 4.x slave to 5.0 is ok (no need to delete relay logs);
so both can be "hot" upgrades.
Upgrading a 3.23 master to 5.0 requires as much as upgrading it to 4.0.
3.23 and 4.x can't be slaves of 5.0.
So downgrading from 5.0 to 4.x may be complicated.
Log_event::log_pos is now the position of the end of the event, which is
more useful than the position of the beginning. We take care about compatibility
with <5.0 (in which log_pos is the beginning).
I added a short test for replication of SQL_MODE and some other variables.
TODO:
- after committing this, merge the latest 5.0 into it
- fix all tests
- update the manual with upgrade notes.
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).
"CHANGE MASTER makes SQL thread restart from coordinates of I/O thread".
So, in CHANGE MASTER:
when it seems reasonable that the user did not want to discontinue
its replication (i.e. when he is not specifying host or port or master_log_file
or master_log_pos; this will be documented), set the coordinates of the
I/O thread to those of the SQL thread. This way, the SQL thread will see
no discontinuity in the relay log (i.e. will skip no events), because
the I/O thread will fill the brand new relay log with the events which
are just after the position where the SQL thread had stopped
(before CHANGE MASTER was issued).
And a new test for this bug.
"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.
WL#604 Privileges in embedded library
code added to check privileges in embedded library
NO_EMBEDDED_ACCESS_CHECKS macros inserted in code so we can exclude
access-checking parts. Actually we now can exclude these parts from
standalone server as well. Do we need it?
Access checks are disabled in embedded server by default. One should
edit libmysqld/Makefile manually to get this working.
We definitely need the separate configure for embedded server
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
For example the Binlog_dump thread (on the master) sometimes showed "Slave:".
And there were confusing messages where "binlog" was employed instead
of "relay log".
"LOAD DATA INFILE is badly filtered by binlog-*-db rules".
There will probably be a second final one to merge Dmitri's changes
to rpl_log.result and mine.
2 new tests:
rpl_loaddata_rule_m : test of logging of LOAD DATA INFILE when the master has binlog-*-db rules,
rpl_loaddata_rule_s : test of logging of LOAD DATA INFILE when the slave has binlog-*-db rules and --log-slave-updates.
- 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.
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)
so I commit again in a fresh tree.
Fix for bug#763 (Relay_log_space too big by 4 bytes),
plus comments and DBUG_PRINT, and we don't start replication
if --bootstrap.
support issue with an unclear message which can have N reasons for appearing.
This should help us know at which point it failed, and get the errno when
my_open was involved (as the reason for the unclear message is often a
permission problem).
RESET SLAVE resets last_error and last_errno in SHOW SLAVE STATUS (without this,
rpl_loaddata.test, which is expected to generate an error in last_error, influenced
rpl_log_pos.test).
A small test update.
Added STOP SLAVE to mysql-test-run to get rid of several stupid error messages
which are printed while the master restarts and the slave attempts/manages to
connect to it and sends it nonsense binlog requests.
Plus a changeset which I had committed but forgot to push (and this changeset is lost on
another computer, so I recreate it here). This changeset is "user-friendly SHOW BINLOG EVENTS
and CHANGE MASTER TO when log positions < 4 are used.
Here is another pack of changes about gathering common client code in
sql-common/client.c.
Now i symlink the client.c from sql/ and libmysql/. These directories
have client_settings.h files to be included to client.c. It contains
defines and declarations to compile client.c in appropriate manner.
Also i've added include/sql_common.h, containing declarations of what
is exported from client.c
I removed as many #ifdef-s from client.c as i dared to. I think it's better
push it with some extra #ifdef-s now (of course, if everythihg besides it is
ok) so other people can check the code.
