Several system variables did not behave like system variables should do.
When trying to SET them or use them in SELECT, they were reported as
"unknown system variable". But they appeared in SHOW VARIABLES.
This has been fixed by removing the "fixed_vars" array of variables
and integrating the variables into the normal system variables chain.
All of these variables do now behave as read-only global-only
variables. Trying to SET them tells they are read-only, trying to
SELECT the session value tells they are global only. Selecting the
global value works. It delivers the same value as SHOW VARIABLES.
In order to handle CHAR() fields, 8 bits were reserved for
the size of the CHAR field. However, instead of denoting the
number of characters in the field, field_length was used which
denotes the number of bytes in the field.
Since UTF-8 fields can have three bytes per character (and
has been extended to have four bytes per character in 6.0),
an extra two bits have been encoded in the field metadata
work for fields of type Field_string (i.e., CHAR fields).
Since the metadata word is filled, the extra bits have been
encoded in the upper 4 bits of the real type (the most
significant byte of the metadata word) by computing the
bitwise xor of the extra two bits. Since the upper 4 bits
of the real type always is 1111 for Field_string, this
means that for fields of length <256, the encoding is
identical to the encoding used in pre-5.1.26 servers, but
for lengths of 256 or more, an unrecognized type is formed,
causing an old slave (that does not handle lengths of 256
or more) to stop.
The crash appeared to be a result of allocating an instance of Discrete_interval
automatically that that was referred in out-of-declaration scope.
Fixed with correcting backing up and restoring scheme of
auto_inc_intervals_forced, introduced by bug#33029, by means of shallow copying;
added simulation code that forces executing those fixes of the former bug that
targeted at master-and-slave having incompatible bug#33029-prone versions.
using a trig in SP
For all 5.0 and up to 5.1.12 exclusive, when a stored routine or
trigger caused an INSERT into an AUTO_INCREMENT column, the
generated AUTO_INCREMENT value should not be written into the
binary log, which means if a statement does not generate
AUTO_INCREMENT value itself, there will be no Intvar event (SET
INSERT_ID) associated with it even if one of the stored routine
or trigger caused generation of such a value. And meanwhile, when
executing a stored routine or trigger, it would ignore the
INSERT_ID value even if there is a INSERT_ID value available set
by a SET INSERT_ID statement.
Starting from MySQL 5.1.12, the generated AUTO_INCREMENT value is
written into the binary log, and the value will be used if
available when executing the stored routine or trigger.
Prior fix of this bug in MySQL 5.0 and prior MySQL 5.1.12
(referenced as the buggy versions in the text below), when a
statement that generates AUTO_INCREMENT value by the top
statement was executed in the body of a SP, all statements in the
SP after this statement would be treated as if they had generated
AUTO_INCREMENT by the top statement. When a statement that did
not generate AUTO_INCREMENT value by the top statement but by a
function/trigger called by it, an erroneous Intvar event would be
associated with the statement, this erroneous INSERT_ID value
wouldn't cause problem when replicating between masters and
slaves of 5.0.x or prior 5.1.12, because the erroneous INSERT_ID
value was not used when executing functions/triggers. But when
replicating from buggy versions to 5.1.12 or newer, which will
use the INSERT_ID value in functions/triggers, the erroneous
value will be used, which would cause duplicate entry error and
cause the slave to stop.
The patch for 5.1 fixed it to ignore the SET INSERT_ID value when
executing functions/triggers if it is replicating from a master
of buggy versions, another patch for 5.0 fixed it not to generate
the erroneous Intvar event.
Problem: if the IO slave thread is attempting to connect,
STOP SLAVE waits for the attempt to finish.
It may take a long time.
Fix: don't wait, stop the slave immediately.
MASTER_POS_WAIT return values are different than expected when the server is not a slave.
It returns -1 instead of NULL.
Fixed with correcting st_relay_log_info::wait_for_pos() to return the proper
value in the case of rli info is not inited.
log-slave-updates and circul repl
Slave SQL thread may execute one extra event when there are events
skipped by slave I/O thread (e.g. originated by the same server).
Whereas it was requested not to do so by the UNTIL condition.
This happens because we compare with the end position of previously
executed event. This is fine when there are no skipped by slave I/O
thread events, as end position of previous event equals to start
position of to be executed event. Otherwise this position equals to
start position of skipped event.
This is fixed by:
- reading the event to be executed before checking if the until condition
is satisfied.
- comparing the start position of the event to be executed. Since we do
not have the start position available, we compute it by subtracting
event length from end position (which is available).
- if there are no events on the event queue at the slave sql starting
time, that meet until condition, we stop immediately, as in this
case we do not want to wait for next event.
"Server_IO_State" field
Critical error messages from get_master_version_and_clock() were written
only to the slave errorlog while Show slave status did not display any
incident happened.
Although the artifact was reported for a particular --replicate-same-server-id
related issue the fix refines all critical error reporting with
deploying rli->report().
The test for the bug covers only --replicate-same-server-id error reporting.
and
bug#33932 assertion at handle_slave_sql if init_slave_thread() fails
the asserts were caused by
bug33931: having thd deleted at time of executing err: code plus
a missed initialization;
bug33932: initialization of slave_is_running member was missed;
fixed with relocating mi members initialization and removing delete thd
It is safe to do as deletion happens later explicitly in the caller of
init_slave_thread().
Todo: at merging the test is better to be moved into suite/bugs for 5.x (when x>0).
to leave
The artifact was caused by
a flaw in concurrent accessing the slave's io thd by
the io itself and a handling show slave status thread.
Namely, show_master_info did not acquire mi->run_lock mutex that is
specified for mi->io_thd member.
Fixed with deploying the mutex locking and unlocking. The mutex is kept
short time and without interleaving with mi->data_lock mutex.
Todo: to report and fix an issue with
sys_var_slave_skip_counter::{methods}
seem to acquire incorrectly
active_mi->rli.run_lock
instead of the specified
active_mi->rli.data_lock
A test case is difficult to compose, so rpl_packet should continue serving
as the indicator.
Complementary patch since LOAD DATA INFILE was not covered in
the previous patch.
This patch adds a check so that the slave skip counter is not
decreased to zero if seeing a BEGIN_LOAD_QUERY_EVENT,
APPEND_BLOCK_EVENT, or CREATE_FILE_EVENT since these cannot
end a group. The group is terminated by an EXECUTE_LOAD_QUERY_
EVENT or DELETE_FILE_EVENT.
Problem: it is unsafe to read base64-printed events without first
reading the Format_description_log_event (FD). Currently, mysqlbinlog
cannot print the FD.
As a side effect, another bug has also been fixed: When mysqlbinlog
--start-position=X was specified, no ROLLBACK was printed. I changed
this, so that ROLLBACK is always printed.
This patch does several things:
- Format_description_log_event (FD) now print themselves in base64
format.
- mysqlbinlog is now able to print FD events. It has three modes:
--base64-output=auto Print row events in base64 output, and print
FD event. The FD event is printed even if
it is outside the range specified with
--start-position, because it would not be
safe to read row events otherwise. This is
the default.
--base64-output=always Like --base64-output=auto, but also print
base64 output for query events. This is
like the old --base64-output flag, which
is also a shorthand for
--base64-output=always
--base64-output=never Never print base64 output, generate error if
row events occur in binlog. This is
useful to suppress the FD event in binlogs
known not to contain row events (e.g.,
because BINLOG statement is unsafe,
requires root privileges, is not SQL, etc)
- the BINLOG statement now handles FD events correctly, by setting
the thread's rli's relay log's description_event_for_exec to the
loaded event.
In fact, executing a BINLOG statement is almost the same as reading
an event from a relay log. Before my patch, the code for this was
separated (exec_relay_log_event in slave.cc executes events from
the relay log, mysql_client_binlog_statement in sql_binlog.cc
executes BINLOG statements). I needed to augment
mysql_client_binlog_statement to do parts of what
exec_relay_log_event does. Hence, I did a small refactoring and
moved parts of exec_relay_log_event to a new function, which I
named apply_event_and_update_pos. apply_event_and_update_pos is
called both from exec_relay_log_event and from
mysql_client_binlog_statement.
- When a non-FD event is executed in a BINLOG statement, without
previously executing a FD event in a BINLOG statement, it generates
an error, because that's unsafe. I took a new error code for that:
ER_NO_FORMAT_DESCRIPTION_EVENT_BEFORE_BINLOG_STATEMENTS.
In order to get a decent error message containing the name of the
event, I added the class method char*
Log_event::get_type_str(Log_event_type type), which returns a
string name for the given Log_event_type. This is just like the
existing char* Log_event::get_type_str(), except it is a class
method that takes the log event type as parameter.
I also added PRE_GA_*_ROWS_LOG_EVENT to Log_event::get_type_str(),
so that names of old rows event are properly printed.
- When reading an event, I added a check that the event type is known
by the current Format_description_log_event. Without this, it may
crash on bad input (and I was struck by this several times).
- I patched the following test cases, which all contain BINLOG
statements for row events which must be preceded by BINLOG
statements for FD events:
- rpl_bug31076
While I was here, I fixed some small things in log_event.cc:
- replaced hard-coded 4 by EVENT_TYPE_OFFSET in 3 places
- replaced return by DBUG_VOID_RETURN in one place
- The name of the logfile can be '-' to indicate stdin. Before my
patch, the code just checked if the first character is '-'; now it
does a full strcmp(). Probably, all arguments that begin with a -
are already handled somewhere else as flags, but I still think it
is better that the code reflects what it is supposed to do, with as
little dependencies as possible on other parts of the code. If we
one day implement that all command line arguments after -- are
files (as most unix tools do), then we need this.
I also fixed the following in slave.cc:
- next_event() was declared twice, and queue_event was not static but
should be static (not used outside the file).
cause ROLLBACK of statement", part 1. Review fixes.
Do not send OK/EOF packets to the client until we reached the end of
the current statement.
This is a consolidation, to keep the functionality that is shared by all
SQL statements in one place in the server.
Currently this functionality includes:
- close_thread_tables()
- log_slow_statement().
After this patch and the subsequent patch for Bug#12713, it shall also include:
- ha_autocommit_or_rollback()
- net_end_statement()
- query_cache_end_of_result().
In future it may also include:
- mysql_reset_thd_for_next_command().
Problem:
The "Slave I/O thread couldn't register on master" error sporadically
occurred in replication tests because the slave I/O thread got
killed by STOP SLAVE before or while registering on master.
Fixed by checking the state of the I/O thread, and issueing
the error only if it was not explicitely killed by a user.
