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.
Fixed that GRANT ... REQUIRE options are not forgot when doing new GRANT
Changed fn_ext to point at first '.' after directory.
FLUSH LOGS removed numerical extension for all future update logs.
Fixed the mysqld --help reports right values for --datadir and --bind-address
--log-binary=a.b.c now properly strips of .b.c
Fix that one can DROP UDF functions that was not loaded at startup
Made AND optional in REQUIRE
Added REQUIRE NONE
Fixes for building MySQL with gcc 3.0
Added SIGNED / UNSIGNED casts
Fixed core dump bug in net_clear() with libmysqld.
Back to using semaphores in query cache.
Added 'Null' and 'Index_type' to SHOW INDEX.
added set_exec_stdout and set_exec_stderr to mysqlmanager to be able
to redirect stdout and stderr
added support for MY_FULL_IO to my_read, so we can tell it to read
a number of bytes in as many chunks as it takes instead of one try
