Implement @@gtid_binlog_state. This is the internal state of the binlog
(most recent GTID logged for every domain_id and server_id). This allows
to save the state before RESET MASTER and restore it afterwards.
The main bug here was the following situation:
Suppose we set up a completely new master2 as an extra multi-master to an
existing slave that already has a different master1 for domain_id=0. When the
slave tries to connect to master2, master2 will not have anything that slave
requests in domain_id=0, but that is fine as master2 is supposedly meant to
serve eg. domain_id=1. (This is MDEV-4485).
But suppose that master2 then actually starts sending events from
domain_id=0. In this case, the fix for MDEV-4485 was incomplete, and the code
would fail to give the error that the position requested by the slave in
domain_id=0 was missing from the binlogs of master2. This could lead to lost
events or completely wrong replication.
The patch for this bug fixes this issue.
In addition, it cleans up the code a bit, getting rid of the fake_gtid_hash in
the code. And the error message when slave and master have diverged due to
alternate future is clarified, as requested in the bug description.
Fix problems related to reconnect. When we need to reconnect (ie. explict
stop/start of just the IO thread by user, or automatic reconnect due to
loosing network connection with the master), it is a bit complex to correctly
resume at the right point without causing duplicate or missing events in the
relay log. The previous code had multiple problems in this regard.
With this patch, the problem is solved as follows. The IO thread keeps track
(in memory) of which GTID was last queued to the relay log. If it needs to
reconnect, it resumes at that GTID position. It also counts number of events
received within the last, possibly partial, event group, and skips the same
number of events after a reconnect, so that events already enqueued before the
reconnect are not duplicated.
(There is no need to keep any persistent state; whenever we restart slave
threads after both of them being stopped (such as after server restart), we
erase the relay logs and start over from the last GTID applied by SQL thread.
But while the SQL thread is running, this patch is needed to get correct relay
log).
There were several cases where the slave GTID position was not loaded
correctly before being used. This caused various failures such as
corrupting the position at slave start and empty values of
@@gtid_slave_pos and @@gtid_current_pos.
Fixed by adding more checks for loaded position, and by always loading
the position at server startup.
When @@GLOBAL.gtid_strict_mode=1, then certain operations result
in error that would otherwise result in out-of-order binlog files
between servers.
GTID sequence numbers are now allocated independently per domain;
this results in less/no holes in GTID sequences, increasing the
likelyhood that diverging binlogs will be caught by the slave when
GTID strict mode is enabled.
Change of user interface to be more logical and more in line with expectations
to work similar to old-style replication.
User can now explicitly choose in CHANGE MASTER whether binlog position is
taken into account (master_gtid_pos=current_pos) or not (master_gtid_pos=
slave_pos) when slave connects to master.
@@gtid_pos is replaced by three separate variables @@gtid_slave_pos (can
be set by user, replicated GTIDs only), @@gtid_binlog_pos (read only), and
@@gtid_current_pos (a combination of the two, most recent GTID within each
domain). mysql.rpl_slave_state is renamed to mysql.gtid_slave_pos to match.
This fixes MDEV-4474.
Implement START SLAVE UNTIL master_gtid_pos = "<GTID position>".
Add test cases, including a test showing how to use this to promote
a new master among a set of slaves.
Merge of 10.0-mdev26 feature tree into 10.0-base.
Global transaction ID is prepended to each event group in the binlog.
Slave connect can request to start from GTID position instead of specifying
file name/offset of master binlog. This facilitates easy switch to a new
master.
Slave GTID state is stored in a table mysql.rpl_slave_state, which can be
InnoDB to get crash-safe slave state.
GTID includes a replication domain ID, allowing to keep track of distinct
positions for each of multiple masters.
* print "table doesn't exist in engine" when a table doesn't exist in the engine,
instead of "file not found" (if no file was involved)
* print a complete filename that cannot be found ('t1.MYI', not 't1')
* it's not an error for a DROP if a table doesn't exist in the engine (or some table
files cannot be found) - if the DROP succeeded regardless
Replace CHANGE MASTER TO ... master_gtid_pos='xxx' with a new system
variable @@global.gtid_pos.
This is more logical; @@gtid_pos is global, not per-master, and it is not
affected by RESET SLAVE.
Also rename master_gtid_pos=AUTO to master_use_gtid=1, which again is more
logical.
Fix MDEV-4329. When user does CHANGE MASTER TO
MASTER_GTID_POS='<explicit GTID state>', we check that this state
does not conflict with the binlog. But the code forgot to give an
error in the case where a domain was completely missing from the
requested position (eg. MASTER_GTID_POS='').
Fix things so that a master can switch with MASTER_GTID_POS=AUTO to a slave
that was previously running with log_slave_updates=0, by looking into the
slave replication state on the master when the slave requests something not
present in the binlog.
Be a bit more strict about what position the slave can ask for, to avoid some
easy-to-hit misconfiguration errors.
Start over with seq_no counter when RESET MASTER.
Improvements to record_gtid():
- Check for correct table definition of mysql.rpl_slave_state
- Use autocommit, to save one call to ha_commit_trans()
- Slightly more efficient way to set table->write_set
- Use ha_index_read_map() to locate rows to support any storage engine.
Remove the two-component form of GTID with implicit domain_id=0, as it
is likely to cause more confusion than help.
Give a better error for CHANGE MASTER ... MASTER_GTID_POS='gtid,gitd,...'
when two specified GTIDs have conflicting domain_id.
This allows us to avoid calculating variables (including those involving mutex) that doesn't match the given
wildcard in SHOW STATUS LIKE '...'
Removed all references to active_mi that could cause problems for multi-source replication.
Added START|STOP ALL SLAVES
Added SHOW ALL SLAVES STATUS
include/mysql/plugin.h:
Added SHOW_SIMPLE_FUNC
include/mysql/plugin_audit.h.pp:
Updated .pp file
include/mysql/plugin_auth.h.pp:
Updated .pp file
include/mysql/plugin_ftparser.h.pp:
Updated .pp file
mysql-test/suite/multi_source/info_logs.result:
New columns in SHOW ALL SLAVES STATUS
mysql-test/suite/multi_source/info_logs.test:
Test new syntax
mysql-test/suite/multi_source/simple.result:
New columns in SHOW ALL SLAVES STATUS
mysql-test/suite/multi_source/simple.test:
test new syntax
mysql-test/suite/multi_source/syntax.result:
Updated result
mysql-test/suite/multi_source/syntax.test:
Test new syntax
mysql-test/suite/rpl/r/rpl_skip_replication.result:
Updated result
plugin/semisync/semisync_master_plugin.cc:
SHOW_FUNC -> SHOW_SIMPLE_FUNC
sql/item_create.cc:
Simplify code
sql/lex.h:
Added SLAVES keyword
sql/log.cc:
Constant -> define
sql/log_event.cc:
Added comment
sql/mysqld.cc:
SHOW_FUNC -> SHOW_SIMPLE_FUNC
Made slave_retried_trans, slave_received_heartbeats and heartbeat_period multi-source safe
Clear variable denied_connections and slave_retried_transactions on startup
sql/mysqld.h:
Added slave_retried_transactions
sql/rpl_mi.cc:
create_signed_file_name -> create_logfile_name_with_suffix
Added start_all_slaves() and stop_all_slaves()
sql/rpl_mi.h:
Added prototypes
sql/rpl_rli.cc:
create_signed_file_name -> create_logfile_name_with_suffix
added executed_entries
sql/rpl_rli.h:
Added executed_entries
sql/share/errmsg-utf8.txt:
More and better error messages
sql/slave.cc:
Added more fields to SHOW ALL SLAVES STATUS
Added slave_retried_transactions
Changed constants -> defines
sql/sql_class.h:
Added comment
sql/sql_insert.cc:
active_mi.rli -> thd->rli_slave
sql/sql_lex.h:
Added SQLCOM_SLAVE_ALL_START & SQLCOM_SLAVE_ALL_STOP
sql/sql_load.cc:
active_mi.rli -> thd->rli_slave
sql/sql_parse.cc:
Added START|STOP ALL SLAVES
sql/sql_prepare.cc:
Added SQLCOM_SLAVE_ALL_START & SQLCOM_SLAVE_ALL_STOP
sql/sql_reload.cc:
Made REFRESH RELAY LOG multi-source safe
sql/sql_repl.cc:
create_signed_file_name -> create_logfile_name_with_suffix
Don't send my_ok() from start_slave() or stop_slave() so that we can call it for all master connections
sql/sql_show.cc:
Compare wild cards early for all variables
sql/sql_yacc.yy:
Added START|STOP ALL SLAVES
Added SHOW ALL SLAVES STATUS
sql/sys_vars.cc:
Made replicate_events_marked_for_skip,slave_net_timeout and rpl_filter multi-source safe.
sql/sys_vars.h:
Simplify Sys_var_rpl_filter
- Added parameter to reset_logs() so that one can specify if new logs should be created.
mysql-test/include/setup_fake_relay_log.inc:
There is no orphan relay log files anymore
mysql-test/mysql-test-run.pl:
Added multi_source to test suite
mysql-test/suite/multi_source/info_logs.result:
New test
mysql-test/suite/multi_source/info_logs.test:
New test
mysql-test/suite/multi_source/my.cnf:
Added log-warnings to get more information to the log files
mysql-test/suite/multi_source/relaylog_events.result:
Added cleanup
mysql-test/suite/multi_source/relaylog_events.test:
Added cleanup
mysql-test/suite/multi_source/reset_slave.result:
Updated results after improved RESET SLAVE
mysql-test/suite/multi_source/simple.result:
Updated results after improved RESET SLAVE
mysql-test/suite/multi_source/simple.test:
Syncronize positions before show full slave status
mysql-test/suite/rpl/r/rpl_row_show_relaylog_events.result:
Updated results after improved RESET SLAVE (we now use less relay log files)
mysql-test/suite/rpl/r/rpl_stm_mix_show_relaylog_events.result:
Updated results after improved RESET SLAVE (we now use less relay log files)
sql/log.cc:
Added parameter to reset_logs() so that one can specify if new logs should be created.
sql/log.h:
Added parameter to reset_logs()
sql/rpl_mi.cc:
Create Master_info_index::index_file_names once at init
More DBUG_PRINT
Give error if Master_info_index::check_duplicate_master_info fails
sql/rpl_rli.cc:
If we do a full reset, don't create any new relay log files.
sql/share/errmsg-utf8.txt:
Improved error message if connection exists
sql/sql_parse.cc:
Fixed memory leak
sql/sql_repl.cc:
check_duplicate_master_info() now generates an error
Added parameter to reset_logs()
Documentation of the feature can be found at: http://kb.askmonty.org/en/multi-source-replication/
This code is based on code from Taobao, developed by Plinux
BUILD/SETUP.sh:
Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
client/mysqltest.cc:
Added support for error names starting with 'W'
Added connection_name support to --sync_with_master
cmake/maintainer.cmake:
Added -Wno-invalid-offsetof to get rid of warning of offsetof() on C++ class (safe in the contex we use it)
mysql-test/r/mysqltest.result:
Updated results
mysql-test/r/parser.result:
Updated results
mysql-test/suite/multi_source/my.cnf:
Setup of multi-master tests
mysql-test/suite/multi_source/simple.result:
Simple basic test of multi-source functionality
mysql-test/suite/multi_source/simple.test:
Simple basic test of multi-source functionality
mysql-test/suite/multi_source/syntax.result:
Test of multi-source syntax
mysql-test/suite/multi_source/syntax.test:
Test of multi-source syntax
mysql-test/suite/rpl/r/rpl_rotate_logs.result:
Updated results because of new error messages
mysql-test/t/parser.test:
Updated test as master_pos_wait() now takes more arguments than before
sql/event_scheduler.cc:
No reason to initialize slave_thread (it's guaranteed to be zero here)
sql/item_create.cc:
Added connection_name argument to master_pos_wait()
Simplified code
sql/item_func.cc:
Added connection_name argument to master_pos_wait()
sql/item_func.h:
Added connection_name argument to master_pos_wait()
sql/log.cc:
Added tag "Master 'connection_name'" to slave errors that has a connection name.
sql/mysqld.cc:
Added variable mysqld_server_initialized so that other functions can test if server is fully initialized.
Free all slave data in one place (fewer ifdef's)
Removed not needed call to close_active_mi()
Initialize slaves() later in startup to ensure that everthing is really initialized when slaves start.
Made status variable slave_running multi-source safe
sql/mysqld.h:
Added mysqld_server_initialized
sql/rpl_mi.cc:
Store connection name and cmp_connection_name (only used for show full slave status) in Master_info
Added code for Master_info_index, which handles storage of multi-master information
Don't write the empty "" connection_name to multi-master.info file. This is handled by the original code.
sql/rpl_mi.h:
Added connection_name and Master_info_index
sql/rpl_rli.cc:
Added connection_name to relay log files.
sql/rpl_rli.h:
Fixed type of slave_skip_counter as we now access it directly in sys_vars.cc, so it must be uint
sql/share/errmsg-utf8.txt:
Added new error messages needed for multi-source
Added multi-source name to error ER_MASTER_INFO and WARN_NO_MASTER_INFO
sql/slave.cc:
Moved things a bit around to make it easier to handle error conditions.
Create a global master_info_index and add the "" connection to it
Ensure that new Master_info doesn't fail.
Don't call terminate_slave_threads(active_mi..) on end_slave() as this is now done automaticly when deleting master_info_index.
Delete not needed function close_active_mi(). One can achive same thing by calling end_slave().
Added support for SHOW FULL SLAVE STATUS (show status for all master connections with connection_name as first column)
sql/slave.h:
Added new prototypes
sql/sql_base.cc:
More DBUG_PRINT
sql/sql_class.cc:
Reset thd->connection_name and thd-->default_master_connection
sql/sql_class.h:
Added thd->connection_name and thd-->default_master_connection
Added slave_skip_count to variables to make changing the @@sql_slave_skip_count variable thread safe
sql/sql_const.h:
Added MAX_CONNECTION_NAME
sql/sql_lex.cc:
Reset 'lex->verbose' (to simplify some sql_yacc.yy code)
sql/sql_lex.h:
Added connection_name
sql/sql_parse.cc:
Added support for connection_name to all SLAVE commands.
- Instead of using active_mi, we now get the current Master_info from master_info_index.
- Create new replication threads with CHANGE MASTER
- Added support for show_all_master_info()
sql/sql_reload.cc:
Made reset/full slave use master_info_index->get_master_info() instead of active_mi.
If one uses 'RESET SLAVE "connection_name" all' the connection is removed from master_info_index.
sql/sql_repl.cc:
sql_slave_skip_counter is moved to thd->variables to make it thread safe and fix some bugs with it
Add connection name to relay log files.
Added connection name to errors.
Added some logging for multi-master if log_warnings > 1
stop_slave():
- Don't check if thd is set. It's guaranteed to always be set.
change_master():
- Check for duplicate connection names in change_master()
- Check for wrong arguments first in file (to simplify error handling)
- Register new connections in master_info_index
sql/sql_yacc.yy:
Added optional connection_name to a all relevant master/slave commands
sql/strfunc.cc:
my_global.h shoud always be included first.
sql/sys_vars.cc:
Added variable default_master_connection
Made variable sql_slave_skip_counter multi-source safe
sql/sys_vars.h:
Added Sys_var_session_lexstring (needed for default_master_connection)
Added Sys_var_multi_source_uint (needed for sql_slave_skip_counter).
NUMBERS
If a system variable was declared as deprecated without mention of an
alternative, the message would look funny, e.g. for @@delayed_insert_limit:
Warning 1287 '@@delayed_insert_limit' is deprecated and
will be removed in MySQL .
The message was meant to display the version number, but it's not
possible to give one when declaring a system variable.
The fix does two things:
1) The definition of the message
ER_WARN_DEPRECATED_SYNTAX_NO_REPLACEMENT is changed so that it does
not display a version number. I.e. in English the message now reads:
Warning 1287 The syntax '@@delayed_insert_limit' is deprecated and
will be removed in a future version.
2) The message ER_WARN_DEPRECATED_SYNTAX_WITH_VER is discontinued in
favor of ER_WARN_DEPRECATED_SYNTAX for system variables. This change
was already done in versions 5.6 and above as part of wl#5265. This
part is simply back-ported from the worklog.
- Changed output to be error "error-text" instead of error - error-text
extra/perror.c:
Move my_handler_errors.h into include
include/my_handler_errors.h:
Move my_handler_errors.h into include
mysql-test/r/errors.result:
Updated result
mysql-test/r/innodb_mysql_sync.result:
Updated result
mysql-test/r/myisam-system.result:
Updated result
mysql-test/r/myisampack.result:
Updated result
mysql-test/r/partition_innodb_plugin.result:
Updated result
mysql-test/r/ps_1general.result:
Updated result
mysql-test/r/trigger.result:
Updated result
mysql-test/r/type_bit.result:
Updated result
mysql-test/r/type_bit_innodb.result:
Updated result
mysql-test/r/type_blob.result:
Updated result
mysql-test/suite/archive/archive.result:
Updated result
mysql-test/suite/binlog/r/binlog_index.result:
Updated result
mysql-test/suite/binlog/r/binlog_ioerr.result:
Updated result
mysql-test/suite/csv/csv.result:
Updated result
mysql-test/suite/engines/iuds/r/type_bit_iuds.result:
Updated result
mysql-test/suite/federated/federated_bug_35333.result:
Updated result
mysql-test/suite/innodb/r/innodb-create-options.result:
Updated result
mysql-test/suite/innodb/r/innodb-index.result:
Updated result
mysql-test/suite/innodb/r/innodb-zip.result:
Updated result
mysql-test/suite/innodb/r/innodb.result:
Updated result
mysql-test/suite/innodb/r/innodb_bug13635833.result:
Updated result
mysql-test/suite/innodb/r/innodb_bug21704.result:
Updated result
mysql-test/suite/innodb/r/innodb_bug46000.result:
Updated result
mysql-test/suite/parts/r/partition_bit_innodb.result:
Updated result
mysql-test/suite/parts/r/partition_bit_myisam.result:
Updated result
mysql-test/suite/percona/percona_innodb_fake_changes.result:
Updated result
mysql-test/suite/perfschema/r/misc.result:
Updated result
mysql-test/suite/perfschema/r/privilege.result:
Updated result
mysql-test/suite/rpl/r/rpl_EE_err.result:
Updated result
mysql-test/suite/rpl/r/rpl_binlog_errors.result:
Updated result
mysql-test/suite/rpl/r/rpl_drop_db.result:
Updated result
sql/share/errmsg-utf8.txt:
Removed 'column' from error text that was used in different context
strings/my_vsnprintf.c:
Move my_handler_errors.h into include
Minor cleanups
Changed output of %M to be error "error-text" instead of error - error-text
unittest/mysys/my_vsnprintf-t.c:
Updated error text
- Adding %M my_sprintf() modifier that prints error number - system-error-text
- Modified mysys, mysql_client and SQL error messages to use %M instead of %d
- Added my_strerror()
Updated handler errors to 5.6 error numbers
Updated text for a few error messages (to match 5.6)
Increased length of command name in error output
extra/comp_err.c:
Added support for %M
include/my_base.h:
Updated handler errors to 5.6 error numbers
include/my_sys.h:
Added my_strerror()
libmysql/errmsg.c:
Updated error messages to use %M
mysql-test/r/errors.result:
Updated result as error message have changed
mysql-test/r/innodb_mysql_sync.result:
Updated result with text for errno
mysql-test/r/myisam-system.result:
Updated result with text for errno
mysql-test/r/myisam.result:
Updated result as error message have changed
mysql-test/r/myisampack.result:
Updated result with text for errno
mysql-test/r/mysql.result:
Updated result with text for errno
mysql-test/r/mysql_upgrade.result:
Updated result with text for errno
mysql-test/r/partition_datatype.result:
Updated result as error message have changed
mysql-test/r/partition_innodb_plugin.result:
Updated result with text for errno
mysql-test/r/ps_1general.result:
Updated result with text for errno
mysql-test/r/trigger.result:
Updated result with text for errno
mysql-test/r/type_bit.result:
Updated result as error message have changed
mysql-test/r/type_bit_innodb.result:
Updated result as error message have changed
mysql-test/r/type_blob.result:
Updated result as error message have changed
mysql-test/suite/archive/archive.result:
Updated result with text for errno
mysql-test/suite/binlog/r/binlog_index.result:
Updated result with text for errno
mysql-test/suite/binlog/r/binlog_ioerr.result:
Updated result with text for errno
mysql-test/suite/csv/csv.result:
Updated result with text for errno
mysql-test/suite/federated/federated_bug_35333.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb-create-options.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb-index.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb-zip.result:
Updated result as error message have changed
mysql-test/suite/innodb/r/innodb.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb_bug21704.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb_bug46000.result:
Updated result with text for errno
mysql-test/suite/innodb/r/innodb_bug53591.result:
Updated result as error message have changed
mysql-test/suite/innodb/r/innodb_corrupt_bit.result:
New error numbers
mysql-test/suite/innodb/r/innodb_prefix_index_liftedlimit.result:
Updated result as error message have changed
mysql-test/suite/innodb/t/innodb-create-options.test:
Added regexp to avoid system error text
mysql-test/suite/innodb/t/innodb-zip.test:
Added regexp to avoid system error text
mysql-test/suite/maria/maria-recovery2.result:
Updated supression rule
mysql-test/suite/maria/maria-recovery2.test:
Updated supression rule
mysql-test/suite/maria/maria.result:
Updated result as error message have changed
mysql-test/suite/parts/r/partition_bit_innodb.result:
Updated result as error message have changed
mysql-test/suite/parts/r/partition_bit_myisam.result:
Updated result as error message have changed
mysql-test/suite/percona/percona_innodb_fake_changes.result:
Updated result with text for errno
mysql-test/suite/perfschema/r/dml_cond_instances.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_events_waits_current.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_events_waits_history.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_events_waits_history_long.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_ews_by_instance.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_ews_by_thread_by_event_name.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_ews_global_by_event_name.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_file_instances.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_file_summary_by_event_name.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_file_summary_by_instance.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_mutex_instances.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_performance_timers.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_rwlock_instances.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/dml_threads.result:
Updated result as error message have changed
mysql-test/suite/perfschema/r/misc.result:
Updated result with text for errno
mysql-test/suite/perfschema/r/privilege.result:
Updated result with text for errno
mysql-test/suite/rpl/r/rpl_EE_err.result:
Updated result with text for errno
mysql-test/suite/rpl/r/rpl_binlog_errors.result:
Updated result with text for errno
mysql-test/suite/rpl/r/rpl_drop_db.result:
Updated result with text for errno
mysys/errors.c:
Updated error messages to use %M
Changed all errors to use Errcode: consistenly
mysys/my_handler_errors.h:
Updated handler errors to 5.6 error numbers
sql/share/errmsg-utf8.txt:
Updated error messages to use %M
sql/sys_vars.cc:
Added error number to ER_EVENT_SET_VAR_ERROR
strings/my_vsnprintf.c:
Added %M my_sprintf() modifier that prints error number - system-error-text
Simplify code
Movied common code to function
Removed some casts that was not necessary when reading integer/unsigned int stored in longlong
Added my_strerror()
unittest/mysys/my_vsnprintf-t.c:
Added testing of %M
TABLES IN INCORRECT ENGINE
PROBLEM:
CREATE/ALTER TABLE currently can move system tables like
mysql.db, user, host etc, to engines other than MyISAM. This is not
completely supported as of now, by mysqld. When some of system tables
like plugin, servers, event, func, *_priv, time_zone* are moved
to innodb, mysqld restart crashes. Currently system tables
can be moved to BLACKHOLE also!!!.
ANALYSIS:
The problem is that there is no check before creating or moving
a system table to some particular engine.
System tables are suppose to be residing in MyISAM. We can think
of restricting system tables to exist only in MyISAM. But, there could
be future needs of these system tables to be part of other engines
by design. For eg, NDB cluster expects some tables to be on innodb
or ndb engine. This calls for a solution, by which system
tables can be supported by any desired engine, with minimal effort.
FIX:
The solution provides a handlerton interface using which,
mysqld server can query particular storage engine handlerton for
system tables that it supports. This way each storage engine
layer can define their own system database and system tables.
The check_engine() function uses the new handlerton function
ha_check_if_supported_system_table() to check if db.tablename
provided in the DDL is supported by the SE.
Note: This fix has modified a test in help.test, which was moving
mysql.help_* to innodb. The primary intention of the test was not
to move them between engines.
