"INSERT... ON DUPLICATE KEY UPDATE skips auto_increment values".
When in an INSERT ON DUPLICATE KEY UPDATE, using
an autoincrement column, we inserted some autogenerated values and
also updated some rows, some autogenerated values were not used
(for example, even if 10 was the largest autoinc value in the table
at the start of the statement, 12 could be the first autogenerated
value inserted by the statement, instead of 11). One autogenerated
value was lost per updated row. Led to exhausting the range of the
autoincrement column faster.
Bug introduced by fix of BUG#20188; present since 5.0.24 and 5.1.12.
This bug breaks replication from a pre-5.0.24 master.
But the present bugfix, as it makes INSERT ON DUP KEY UPDATE
behave like pre-5.0.24, breaks replication from a [5.0.24,5.0.34]
master to a fixed (5.0.36) slave! To warn users against this when
they upgrade their slave, as agreed with the support team, we add
code for a fixed slave to detect that it is connected to a buggy
master in a situation (INSERT ON DUP KEY UPDATE into autoinc column)
likely to break replication, in which case it cannot replicate so
stops and prints a message to the slave's error log and to SHOW SLAVE
STATUS.
For 5.0.36->[5.0.24,5.0.34] replication we cannot warn as master
does not know the slave's version (but we always recommended to users
to have slave at least as new as master).
As agreed with support, I'll also ask for an alert to be put into
the MySQL Network Monitoring and Advisory Service.
Fix when __attribute__() is stubbed out, add ATTRIBUTE_FORMAT() for specifying
__attribute__((format(...))) safely, make more use of the format attribute,
and fix some of the warnings that this turns up (plus a bonus unrelated one).
No test case as the bug is in an existing test case (rpl_trigger.test
when it is run under valgrind).
The warning was caused by memory corruption in replication slave: thd->db
was pointing at a stack address that was previously used by
sp_head::execute()::old_db. This happened because mysql_change_db
behaved differently in replication slave and did not make a copy of the
argument to assign to thd->db.
The solution is to always free the old value of thd->db and allocate a new
copy, regardless whether we're running in a replication slave or not.
Bug#19022 "Memory bug when switching db during trigger execution"
Bug#17199 "Problem when view calls function from another database."
Bug#18444 "Fully qualified stored function names don't work correctly in
SELECT statements"
Documentation note: this patch introduces a change in behaviour of prepared
statements.
This patch adds a few new invariants with regard to how THD::db should
be used. These invariants should be preserved in future:
- one should never refer to THD::db by pointer and always make a deep copy
(strmake, strdup)
- one should never compare two databases by pointer, but use strncmp or
my_strncasecmp
- TABLE_LIST object table->db should be always initialized in the parser or
by creator of the object.
For prepared statements it means that if the current database is changed
after a statement is prepared, the database that was current at prepare
remains active. This also means that you can not prepare a statement that
implicitly refers to the current database if the latter is not set.
This is not documented, and therefore needs documentation. This is NOT a
change in behavior for almost all SQL statements except:
- ALTER TABLE t1 RENAME t2
- OPTIMIZE TABLE t1
- ANALYZE TABLE t1
- TRUNCATE TABLE t1 --
until this patch t1 or t2 could be evaluated at the first execution of
prepared statement.
CURRENT_DATABASE() still works OK and is evaluated at every execution
of prepared statement.
Note, that in stored routines this is not an issue as the default
database is the database of the stored procedure and "use" statement
is prohibited in stored routines.
This patch makes obsolete the use of check_db_used (it was never used in the
old code too) and all other places that check for table->db and assign it
from THD::db if it's NULL, except the parser.
How this patch was created: THD::{db,db_length} were replaced with a
LEX_STRING, THD::db. All the places that refer to THD::{db,db_length} were
manually checked and:
- if the place uses thd->db by pointer, it was fixed to make a deep copy
- if a place compared two db pointers, it was fixed to compare them by value
(via strcmp/my_strcasecmp, whatever was approproate)
Then this intermediate patch was used to write a smaller patch that does the
same thing but without a rename.
TODO in 5.1:
- remove check_db_used
- deploy THD::set_db in mysql_change_db
See also comments to individual files.
in short we now record whenever the slave I/O thread ignores a master's event because of its server id,
and use this info in the slave SQL thread to advance Exec_master_log_pos. Because if we
do not, this variable stays at the position of the last executed event, i.e. the last *non-ignored*
executed one, which may not be the last of the master's binlog (and so the slave *looks* behind
the master though it's data-wise it's not).
Some options were declared as 'bool', but since those are being
handled in my_getopt.c, bool can be machine dependent. To make
sure it works in all circumstances, the type should be my_bool
for C (not C++) programs.
s/sleep/safe_sleep (thread safe); sleep 0/1/2/3/4/5/5/5 (get slave less late);
no message on error log (deadlock is too common sometimes), a global counter
instead (SHOW STATUS LIKE 'slave_retried_transactions').
Plus a fix for libmysql/Makefile.shared
in slave SQL thread: if a transaction fails because of InnoDB deadlock or innodb_lock_wait_timeout exceeded,
optionally retry the transaction a certain number of times (new variable --slave_transaction_retries).
we store 7 bytes (1 + 2*3) in every Query_log_event.
In the future if users want binlog optimized for small size and less safe,
we could add --binlog-no-charset (and binlog-no-sql-mode etc): charset info
is something by design optional (even if for now we don't offer possibility to disable it):
it's not a binlog format change.
We try to reduce the number of get_charset() calls in the slave SQL thread to a minimum
by caching the charset read from the previous event (which will often be equal to the one of the current event).
We don't use SET ONE_SHOT for charset-aware repl (we still do for timezones, will be fixed later).
No more errors if one changes the global value of charset vars on master or slave
(as we log charset info in all Query_log_event).
Not fixing Load_log_event as it will be rewritten soon by Dmitri.
Testing how mysqlbinlog behaves in rpl_charset.test.
mysqlbinlog needs to know where charset file is (to be able to convert a charset number found
in binlog (e.g. in User_var_log_event) to a charset name); mysql-test-run needs to pass
the correct value for this option to mysqlbinlog.
Many result udpates (adding charset info into every event shifts log_pos in SHOW BINLOG EVENTS).
Roughly the same job is to be done for timezones :)
because old behaviour was somewhat nonsensical (kind of bug). Changes are that if repl threads are
down or disconnected the column will be NULL, and if master is idle the column will not grow indefinitely anymore.
1 if the return type is int or int_fast8_t. The test case that showed
this problem is rpl000001 and the tested version was MySQL 5.0.2. The
compiler with the problem is GCC 3.0.4 runing on "Linux bitch 2.4.18
#2 Thu Apr 11 14:37:17 EDT 2002 sparc64 unknown".
By changing the return type to bool the problem disappear. (Another
way to make the problem disappear is to simply print the returned
value with printf("%d",?). The printed returned value is always 0 in
the test cases I have run.) This is only a partial solution to the
problem, since someone could later change the return type of the
function back to int or some other type that does not work.
as we already have db_len in Log_event. Only if rewrite_db() changed the db we need a strlen
(so we now do the strlen() in rewrite_db). Plus a test (we had none for --replicate-rewrite-db :( ).
(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).
