"HANDLER statements within a transaction might lead to deadlocks".
Introduce a notion of a sentinel to MDL_context. A sentinel
is a ticket that separates all tickets in the context into two
groups: before and after it. Currently we can have (and need) only
one designated sentinel -- it separates all locks taken by LOCK
TABLE or HANDLER statement, which must survive COMMIT and ROLLBACK
and all other locks, which must be released at COMMIT or ROLLBACK.
The tricky part is maintaining the sentinel up to date when
someone release its corresponding ticket. This can happen, e.g.
if someone issues DROP TABLE under LOCK TABLES (generally,
see all calls to release_all_locks_for_name()).
MDL_context::release_ticket() is modified to take care of it.
******
A fix and a test case for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".
An attempt to mix HANDLER SQL statements, which are transaction-
agnostic, an open multi-statement transaction,
and DDL against the involved tables (in a concurrent connection)
could lead to a deadlock. The deadlock would occur when
HANDLER OPEN or HANDLER READ would have to wait on a conflicting
metadata lock. If the connection that issued HANDLER statement
also had other metadata locks (say, acquired in scope of a
transaction), a classical deadlock situation of mutual wait
could occur.
Incompatible change: entering LOCK TABLES mode automatically
closes all open HANDLERs in the current connection.
Incompatible change: previously an attempt to wait on a lock
in a connection that has an open HANDLER statement could wait
indefinitely/deadlock. After this patch, an error ER_LOCK_DEADLOCK
is produced.
The idea of the fix is to merge thd->handler_mdl_context
with the main mdl_context of the connection, used for transactional
locks. This makes deadlock detection possible, since all waits
with locks are "visible" and available to analysis in a single
MDL context of the connection.
Since HANDLER locks and transactional locks have a different life
cycle -- HANDLERs are explicitly open and closed, and so
are HANDLER locks, explicitly acquired and released, whereas
transactional locks "accumulate" till the end of a transaction
and are released only with COMMIT, ROLLBACK and ROLLBACK TO SAVEPOINT,
a concept of "sentinel" was introduced to MDL_context.
All locks, HANDLER and others, reside in the same linked list.
However, a selected element of the list separates locks with
different life cycle. HANDLER locks always reside at the
end of the list, after the sentinel. Transactional locks are
prepended to the beginning of the list, before the sentinel.
Thus, ROLLBACK, COMMIT or ROLLBACK TO SAVEPOINT, only
release those locks that reside before the sentinel. HANDLER locks
must be released explicitly as part of HANDLER CLOSE statement,
or an implicit close.
The same approach with sentinel
is also employed for LOCK TABLES locks. Since HANDLER and LOCK TABLES
statement has never worked together, the implementation is
made simple and only maintains one sentinel, which is used either
for HANDLER locks, or for LOCK TABLES locks.
mysql-test/include/handler.inc:
Add test coverage for Bug#46224 "HANDLER statements within a
transaction might lead to deadlocks".
Extended HANDLER coverage to cover a mix of HANDLER, transactions
and DDL statements.
mysql-test/r/handler_innodb.result:
Update results (Bug#46224).
mysql-test/r/handler_myisam.result:
Update results (Bug#46224).
sql/lock.cc:
Remove thd->some_tables_deleted, it's never used.
sql/log_event.cc:
No need to check for thd->locked_tables_mode,
it's done inside release_transactional_locks().
sql/mdl.cc:
Implement the concept of HANDLER and LOCK TABLES "sentinel".
Implement a method to clone an acquired ticket.
Do not return tickets beyond the sentinel when acquiring
locks, create a copy.
Remove methods to merge and backup MDL_context, they are now
not used (Hurra!). This opens a path to a proper constructor
and destructor of class MDL_context (to be done in a separate
patch).
Modify find_ticket() to provide information about where
the ticket position is with regard to the sentinel.
sql/mdl.h:
Add declarations necessary for the implementation of the concept
of "sentinel", a dedicated ticket separating transactional and
non-transactional locks.
sql/mysql_priv.h:
Add mark_tmp_table_for_reuse() declaration,
a function to "close" a single session (temporary) table.
sql/sql_base.cc:
Remove thd->some_tables_deleted.
Modify deadlock-prevention asserts and deadlock detection
heuristics to take into account that from now on HANDLER locks
reside in the same locking context.
Add broadcast_refresh() to mysql_notify_thread_having_shared_lock():
this is necessary for the case when a thread having a shared lock
is asleep in tdc_wait_for_old_versions(). This situation is only
possible with HANDLER t1 OPEN; FLUSH TABLE (since all over code paths
that lead to tdc_wait_for_old_versions() always have an
empty MDL_context). Previously the server would simply deadlock
in this situation.
sql/sql_class.cc:
Remove now unused member "THD::some_tables_deleted".
Move mysql_ha_cleanup() a few lines above in THD::cleanup()
to make sure that all handlers are closed when it's time to
destroy the MDL_context of this connection.
Remove handler_mdl_context and handler_tables.
sql/sql_class.h:
Remove THD::handler_tables, THD::handler_mdl_context,
THD::some_tables_deleted.
sql/sql_handler.cc:
Remove thd->handler_tables.
Remove thd->handler_mdl_context.
Rewrite mysql_ha_open() to have no special provision for MERGE
tables, now that we don't have to manipulate with thd->handler_tables
it's easy to do.
Remove dead code.
Fix a bug in mysql_ha_flush() when we would always flush
a temporary HANDLER when mysql_ha_flush() is called (actually
mysql_ha_flush() never needs to flush temporary tables).
sql/sql_insert.cc:
Update a comment, no more thd->some_tables_deleted.
sql/sql_parse.cc:
Implement an incompatible change: entering LOCK TABLES closes
active HANDLERs, if any.
Now that we have a sentinel, we don't need to check
for thd->locked_tables_mode when releasing metadata locks in
COMMIT/ROLLBACK.
sql/sql_plist.h:
Add new (now necessary) methods to the list class.
sql/sql_prepare.cc:
Make sure we don't release HANDLER locks when rollback to a
savepoint, set to not keep locks taken at PREPARE.
sql/sql_servers.cc:
Update to a new signature of MDL_context::release_all_locks().
sql/sql_table.cc:
Remove thd->some_tables_deleted.
sql/transaction.cc:
Add comments.
Make sure rollback to (MDL) savepoint works under LOCK TABLES and
with HANDLER tables.
Bug#16565 mysqld --help --verbose does not order variablesBug#20413 sql_slave_skip_counter is not shown in show variables
Bug#20415 Output of mysqld --help --verbose is incomplete
Bug#25430 variable not found in SELECT @@global.ft_max_word_len;
Bug#32902 plugin variables don't know their names
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#34829 No default value for variable and setting default does not raise error
Bug#34834 ? Is accepted as a valid sql mode
Bug#34878 Few variables have default value according to documentation but error occurs
Bug#34883 ft_boolean_syntax cant be assigned from user variable to global var.
Bug#37187 `INFORMATION_SCHEMA`.`GLOBAL_VARIABLES`: inconsistent status
Bug#40988 log_output_basic.test succeeded though syntactically false.
Bug#41010 enum-style command-line options are not honoured (maria.maria-recover fails)
Bug#42103 Setting key_buffer_size to a negative value may lead to very large allocations
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#44797 plugins w/o command-line options have no disabling option in --help
Bug#46314 string system variables don't support expressions
Bug#46470 sys_vars.max_binlog_cache_size_basic_32 is broken
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#47212 Crash in DBUG_PRINT in mysqltest.cc when trying to print octal number
Bug#48758 mysqltest crashes on sys_vars.collation_server_basic in gcov builds
Bug#49417 some complaints about mysqld --help --verbose output
Bug#49540 DEFAULT value of binlog_format isn't the default value
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
Bug#49646 mysql --show-warnings crashes when server dies
CMakeLists.txt:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
client/mysql.cc:
don't crash with --show-warnings when mysqld dies
config/ac-macros/plugins.m4:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
include/my_getopt.h:
comments
include/my_pthread.h:
fix double #define
mysql-test/mysql-test-run.pl:
run sys_vars suite by default
properly recognize envirinment variables (e.g. MTR_MAX_SAVE_CORE) set to 0
escape gdb command line arguments
mysql-test/suite/sys_vars/r/rpl_init_slave_func.result:
init_slave+utf8 bug
mysql-test/suite/sys_vars/t/rpl_init_slave_func.test:
init_slave+utf8 bug
mysys/my_getopt.c:
Bug#34599 MySQLD Option and Variable Reference need to be consistent in formatting!
Bug#46586 When using the plugin interface the type "set" for options caused a crash.
Bug#49640 ambiguous option '--skip-skip-myisam' (double skip prefix)
mysys/typelib.c:
support for flagset
sql/ha_ndbcluster.cc:
backport from telco tree
sql/item_func.cc:
Bug#49644 init_connect and \0
Bug#49645 init_slave and multi-byte characters
sql/sql_builtin.cc.in:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
sql/sql_plugin.cc:
Bug#44691 Some plugins configured as MYSQL_PLUGIN_MANDATORY in can be disabled
Bug#32902 plugin variables don't know their names
Bug#44797 plugins w/o command-line options have no disabling option in --help
sql/sys_vars.cc:
all server variables are defined here
storage/myisam/ft_parser.c:
remove unnecessary updates of param->quot
storage/myisam/ha_myisam.cc:
myisam_* variables belong here
strings/my_vsnprintf.c:
%o and %llx
unittest/mysys/my_vsnprintf-t.c:
%o and %llx tests
vio/viosocket.c:
bugfix: fix @@wait_timeout to work with socket timeouts (vs. alarm thread)
2617.31.12, 2617.31.15, 2617.31.15, 2617.31.16, 2617.43.1
- initial changeset that introduced the fix for
Bug#989 and follow up fixes for all test suite failures
introduced in the initial changeset.
------------------------------------------------------------
revno: 2617.31.1
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Fri 2009-03-06 19:17:00 -0300
message:
Bug#989: If DROP TABLE while there's an active transaction, wrong binlog order
WL#4284: Transactional DDL locking
Currently the MySQL server does not keep metadata locks on
schema objects for the duration of a transaction, thus failing
to guarantee the integrity of the schema objects being used
during the transaction and to protect then from concurrent
DDL operations. This also poses a problem for replication as
a DDL operation might be replicated even thought there are
active transactions using the object being modified.
The solution is to defer the release of metadata locks until
a active transaction is either committed or rolled back. This
prevents other statements from modifying the table for the
entire duration of the transaction. This provides commitment
ordering for guaranteeing serializability across multiple
transactions.
- Incompatible change:
If MySQL's metadata locking system encounters a lock conflict,
the usual schema is to use the try and back-off technique to
avoid deadlocks -- this schema consists in releasing all locks
and trying to acquire them all in one go.
But in a transactional context this algorithm can't be utilized
as its not possible to release locks acquired during the course
of the transaction without breaking the transaction commitments.
To avoid deadlocks in this case, the ER_LOCK_DEADLOCK will be
returned if a lock conflict is encountered during a transaction.
Let's consider an example:
A transaction has two statements that modify table t1, then table
t2, and then commits. The first statement of the transaction will
acquire a shared metadata lock on table t1, and it will be kept
utill COMMIT to ensure serializability.
At the moment when the second statement attempts to acquire a
shared metadata lock on t2, a concurrent ALTER or DROP statement
might have locked t2 exclusively. The prescription of the current
locking protocol is that the acquirer of the shared lock backs off
-- gives up all his current locks and retries. This implies that
the entire multi-statement transaction has to be rolled back.
- Incompatible change:
FLUSH commands such as FLUSH PRIVILEGES and FLUSH TABLES WITH READ
LOCK won't cause locked tables to be implicitly unlocked anymore.
mysql-test/extra/binlog_tests/drop_table.test:
Add test case for Bug#989.
mysql-test/extra/binlog_tests/mix_innodb_myisam_binlog.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/include/mix1.inc:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/include/mix2.inc:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/r/flush_block_commit.result:
Update test case result (WL#4284).
mysql-test/r/flush_block_commit_notembedded.result:
Update test case result (WL#4284).
mysql-test/r/innodb.result:
Update test case result (WL#4284).
mysql-test/r/innodb_mysql.result:
Update test case result (WL#4284).
mysql-test/r/lock.result:
Add test case result for an effect of WL#4284/Bug#989
(all locks should be released when a connection terminates).
mysql-test/r/mix2_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/not_embedded_server.result:
Update test case result (effects of WL#4284/Bug#989).
Add a test case for interaction of WL#4284 and FLUSH PRIVILEGES.
mysql-test/r/partition_innodb_semi_consistent.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/r/partition_sync.result:
Temporarily disable the test case for Bug#43867,
which will be fixed by a subsequent backport.
mysql-test/r/ps.result:
Add a test case for effect of PREPARE on transactional
locks: we take a savepoint at beginning of PREAPRE
and release it at the end. Thus PREPARE does not
accumulate metadata locks (Bug#989/WL#4284).
mysql-test/r/read_only_innodb.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_drop_tbl.result:
Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_row_mix_innodb_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_drop_tbl.result:
Add a test case result (WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_stm_mix_innodb_myisam.result:
Update test case result (effects of WL#4284/Bug#989).
mysql-test/suite/binlog/r/binlog_unsafe.result:
A side effect of Bug#989 -- slightly different table map ids.
mysql-test/suite/binlog/t/binlog_row_drop_tbl.test:
Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_drop_tbl.test:
Add a test case for WL#4284/Bug#989.
mysql-test/suite/binlog/t/binlog_stm_row.test:
Update to the new state name. This
is actually a follow up to another patch for WL#4284,
that changes Locked thread state to Table lock.
mysql-test/suite/ndb/r/ndb_index_ordered.result:
Remove result for disabled part of the test case.
mysql-test/suite/ndb/t/disabled.def:
Temporarily disable a test case (Bug#45621).
mysql-test/suite/ndb/t/ndb_index_ordered.test:
Disable a part of a test case (needs update to
reflect semantics of Bug#989).
mysql-test/suite/rpl/t/disabled.def:
Disable tests made meaningless by transactional metadata
locking.
mysql-test/suite/sys_vars/r/autocommit_func.result:
Add a commit (Bug#989).
mysql-test/suite/sys_vars/t/autocommit_func.test:
Add a commit (Bug#989).
mysql-test/t/flush_block_commit.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
mysql-test/t/flush_block_commit_notembedded.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction.
Add a test case for transaction-scope locks and the global
read lock (Bug#989/WL#4284).
mysql-test/t/innodb.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(effects of Bug#989/WL#4284).
mysql-test/t/lock.test:
Add a test case for Bug#989/WL#4284.
mysql-test/t/not_embedded_server.test:
Add a test case for Bug#989/WL#4284.
mysql-test/t/partition_innodb_semi_consistent.test:
Replace TRUNCATE with DELETE, to not issue
an implicit commit of a transaction, and not depend
on metadata locks.
mysql-test/t/partition_sync.test:
Temporarily disable the test case for Bug#43867,
which needs a fix to be backported from 6.0.
mysql-test/t/ps.test:
Add a test case for semantics of PREPARE and transaction-scope
locks: metadata locks on tables used in PREPARE are enclosed into a
temporary savepoint, taken at the beginning of PREPARE,
and released at the end. Thus PREPARE does not effect
what locks a transaction owns.
mysql-test/t/read_only_innodb.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(Bug#989/WL#4284).
Wait for the read_only statement to actually flush tables before
sending other concurrent statements that depend on its state.
mysql-test/t/xa.test:
Fix test case to reflect the fact that transactions now hold
metadata locks for the duration of a transaction
(Bug#989/WL#4284).
sql/ha_ndbcluster_binlog.cc:
Backport bits of changes of ha_ndbcluster_binlog.cc
from 6.0, to fix the failing binlog test suite with
WL#4284. WL#4284 implementation does not work
with 5.1 implementation of ndbcluster binlog index.
sql/log_event.cc:
Release metadata locks after issuing a commit.
sql/mdl.cc:
Style changes (WL#4284).
sql/mysql_priv.h:
Rename parameter to match the name used in the definition (WL#4284).
sql/rpl_injector.cc:
Release metadata locks on commit (WL#4284).
sql/rpl_rli.cc:
Remove assert made meaningless, metadata locks are released
at the end of the transaction.
sql/set_var.cc:
Close tables and release locks if autocommit mode is set.
sql/slave.cc:
Release metadata locks after a rollback.
sql/sql_acl.cc:
Don't implicitly unlock locked tables. Issue a implicit commit
at the end and unlock tables.
sql/sql_base.cc:
Defer the release of metadata locks when closing tables
if not required to.
Issue a deadlock error if the locking protocol requires
that a transaction re-acquire its locks.
Release metadata locks when closing tables for reopen.
sql/sql_class.cc:
Release metadata locks if the thread is killed.
sql/sql_parse.cc:
Release metadata locks after implicitly committing a active
transaction, or after explicit commits or rollbacks.
sql/sql_plugin.cc:
Allocate MDL request on the stack as the use of the table
is contained within the function. It will be removed from
the context once close_thread_tables is called at the end
of the function.
sql/sql_prepare.cc:
The problem is that the prepare phase of the CREATE TABLE
statement takes a exclusive metadata lock lock and this can
cause a self-deadlock the thread already holds a shared lock
on the table being that should be created.
The solution is to make the prepare phase take a shared
metadata lock when preparing a CREATE TABLE statement. The
execution of the statement will still acquire a exclusive
lock, but won't cause any problem as it issues a implicit
commit.
After some discussions with stakeholders it has been decided that
metadata locks acquired during a PREPARE statement must be released
once the statement is prepared even if it is prepared within a multi
statement transaction.
sql/sql_servers.cc:
Don't implicitly unlock locked tables. Issue a implicit commit
at the end and unlock tables.
sql/sql_table.cc:
Close table and release metadata locks after a admin operation.
sql/table.h:
The problem is that the prepare phase of the CREATE TABLE
statement takes a exclusive metadata lock lock and this can
cause a self-deadlock the thread already holds a shared lock
on the table being that should be created.
The solution is to make the prepare phase take a shared
metadata lock when preparing a CREATE TABLE statement. The
execution of the statement will still acquire a exclusive
lock, but won't cause any problem as it issues a implicit
commit.
sql/transaction.cc:
Release metadata locks after the implicitly committed due
to a new transaction being started. Also, release metadata
locks acquired after a savepoint if the transaction is rolled
back to the save point.
The problem is that in some cases transaction-long metadata locks
could be released before the transaction was committed. This could
happen when a active transaction was ended by a "START TRANSACTION"
or "BEGIN" statement, in which case the metadata locks would be
released before the actual commit of the active transaction.
The solution is to defer the release of metadata locks to after the
transaction has been implicitly committed. No test case is provided
as the effort to provide one is too disproportional to the size of
the fix.
------------------------------------------------------------
revno: 2630.22.3
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 4284-6.0
timestamp: Thu 2008-08-07 22:33:43 -0300
message:
WL#4284: Transactional DDL locking
Make transaction management more modular through a new interface.
The overall objective of this change is to provide groundwork
for the design of transactional DDL locking by cleaning up the
transaction high level API to better distinguish operations implicit
and explicit, and single statement transaction from operations on
the normal transaction.
Having a a high-level interface for transaction management provides
a better base for implementing transactional concepts that are not
always tied to storage engines and also makes it easier to interect
with other higher level modules of the server.
client/Makefile.am:
Add new file to the build.
libmysqld/CMakeLists.txt:
Add new file to the build.
libmysqld/Makefile.am:
Add new file to the build.
sql/CMakeLists.txt:
Add new file to the build.
sql/Makefile.am:
Add new file to the build.
sql/handler.cc:
Remove multiplexer commit or rollback function. Most callers already
have enough information to decided whether to rollback or commit.
Having plain and well named functions makes it easier to read
and understand code.
sql/handler.h:
Remove wrapper function as the low level transaction functions
shouldn't be called directly anymore.
sql/log_event.cc:
Rename transaction management functions to the new names.
sql/log_event_old.cc:
Rename transaction management functions to the new names.
sql/mysql_priv.h:
Remove obsolete functions for implicit and explicit commit.
sql/rpl_injector.cc:
Rename transaction management functions to the new names.
sql/rpl_rli.cc:
Rename transaction management functions to the new names.
sql/set_var.cc:
Rename transaction management functions to the new names.
sql/slave.cc:
Rename transaction management functions to the new names.
sql/sql_base.cc:
Rename transaction management functions to the new names.
sql/sql_class.cc:
Rename transaction management functions to the new names.
sql/sql_delete.cc:
Rename transaction management functions to the new names.
sql/sql_do.cc:
Rename transaction management functions to the new names.
sql/sql_insert.cc:
Rename transaction management functions to the new names.
sql/sql_parse.cc:
Rename transaction management functions to the new names.
sql/sql_partition.cc:
Rename transaction management functions to the new names.
sql/sql_table.cc:
Rename transaction management functions to the new names.
sql/transaction.cc:
Implement wrapper functions to differentiate operations on
the single statement transaction from the ones operating
on the normal transaction.
sql/transaction.h:
Export new functions for dealing with transaction commands.
Text conflict in mysql-test/collections/default.experimental
Text conflict in mysql-test/r/show_check.result
Text conflict in mysql-test/r/sp-code.result
Text conflict in mysql-test/suite/binlog/r/binlog_tmp_table.result
Text conflict in mysql-test/suite/rpl/t/disabled.def
Text conflict in mysql-test/t/show_check.test
Text conflict in mysys/my_delete.c
Text conflict in sql/item.h
Text conflict in sql/item_cmpfunc.h
Text conflict in sql/log.cc
Text conflict in sql/mysqld.cc
Text conflict in sql/repl_failsafe.cc
Text conflict in sql/slave.cc
Text conflict in sql/sql_parse.cc
Text conflict in sql/sql_table.cc
Text conflict in sql/sql_yacc.yy
Text conflict in storage/myisam/ha_myisam.cc
Corrected results for
stm_auto_increment_bug33029.reject 2009-12-01
20:01:49.000000000 +0300
<andrei> @@ -42,9 +42,6 @@
<andrei> RETURN i;
<andrei> END//
<andrei> CALL p1();
<andrei> -Warnings:
<andrei> -Note 1592 Statement may not be safe to log in statement
format.
<andrei> -Note 1592 Statement may not be safe to log in statement
format.
There should be indeed no Note present because there is in fact autoincrement
top-level query in sp() that triggers inserting in yet another auto-inc table.
(todo: alert DaoGang to improve the test).
-------------------------------------------------------------
revno: 2877
committer: Davi Arnaut <Davi.Arnaut@Sun.COM>
branch nick: 35164-6.0
timestamp: Wed 2008-10-15 19:53:18 -0300
message:
Bug#35164: Large number of invalid pthread_attr_setschedparam calls
Bug#37536: Thread scheduling causes performance degradation at low thread count
Bug#12702: Long queries take 100% of CPU and freeze other applications under Windows
The problem is that although having threads with different priorities
yields marginal improvements [1] in some platforms [2], relying on some
statically defined priorities (QUERY_PRIOR and WAIT_PRIOR) to play well
(or to work at all) with different scheduling practices and disciplines
is, at best, a shot in the dark as the meaning of priority values may
change depending on the scheduling policy set for the process.
Another problem is that increasing priorities can hurt other concurrent
(running on the same hardware) applications (such as AMP) by causing
starvation problems as MySQL threads will successively preempt lower
priority processes. This can be evidenced by Bug#12702.
The solution is to not change the threads priorities and rely on the
system scheduler to perform its job. This also enables a system admin
to increase or decrease the scheduling priority of the MySQL process,
if intended.
Furthermore, the internal wrappers and code for changing the priority
of threads is being removed as they are now unused and ancient.
1. Due to unintentional side effects. On Solaris this could artificially
help benchmarks as calling the priority changing syscall millions of
times is more beneficial than the actual setting of the priority.
2. Where it actually works. It has never worked on Linux as the default
scheduling policy SCHED_OTHER only accepts the static priority 0.
configure.in:
Remove checks for functions that are not used anymore.
include/config-netware.h:
Remove unused define.
include/my_pthread.h:
Remove thread priority changing wrappers.
mysys/my_pthread.c:
Remove thread priority changing wrappers. They do not work properly
and their implementations were incorrectly protected by a check for
HAVE_PTHREAD_SETSCHEDPARAM.
mysys/thr_alarm.c:
Remove meaningless (100) increase of a thread priority.
sql/mysql_priv.h:
Remove meaningless thread priority values.
sql/mysqld.cc:
Don't change thread priorities.
sql/slave.cc:
Don't change thread priorities.
sql/slave.h:
Update function prototype.
sql/sql_parse.cc:
Don't change thread priorities.
sql/sql_prepare.cc:
Don't change thread priorities.
sql/unireg.h:
Mark flag as obsolete.
storage/innobase/handler/ha_innodb.cc:
Remove use of obsolete flag and associated behavior.
storage/innobase/include/srv0srv.h:
Remove use of obsolete flag and associated variables.
storage/innobase/os/os0thread.c:
Remove use of obsolete flag and associated behavior.
storage/innobase/srv/srv0srv.c:
Remove use of obsolete flag and associated variables.
The mentioned on the bug report set of bugs fixes have not be pushed to the main trees.
Fixed with extracting commits done to 6.0-rpl tree and applying them to the main 5.1.
Notes.
1. part of changes - the mtr's specific - were packported to the main 5.0 tree for mtr v1
as http://lists.mysql.com/commits/46562
However, there is no that fix anymore in the mtr v2. (This fact was mailed to mtr maintaining
people).
2. Bug@36929 crash in kill_zombie_dump_threads-> THD::awake() with replication tests
is not backported because the base code of the patch is libevent and that was removed
from the main trees due to its instability.
client/mysqlbinlog.cc:
fixes for BUG#35546
mysql-test/suite/rpl/r/rpl_bug41902.result:
the new tests result file is added.
mysql-test/suite/rpl/t/rpl_bug41902-slave.opt:
conf file for bug41902 testing is added.
mysql-test/suite/rpl/t/rpl_bug41902.test:
regression tests for Bug #41902 is added.
sql/log.cc:
collection of changes due to Bug #48463.
sql/log.h:
collection of changes due to Bug #48463.
sql/rpl_rli.h:
collection of changes due to Bug #48463.
sql/slave.cc:
collection of changes due to Bug #48463.
sql/sql_repl.cc:
collection of changes due to Bug #48463.
port from mysql-next (5.4?) to mysql-next-mr-bugfixes (5.5/5.6?)
3477 Mikael Ronstrom 2009-07-29
Bug#32115, made use of local lex object to avoid side effects of opening partitioned
tables
3478 Mikael Ronstrom 2009-07-29
Bug#32115, added an extra test in debug builds to ensure no dangling pointers to the
old lex object is still around
3479 Mikael Ronstrom 2009-07-29
Bug#32115, Removed an assert that was no longer needed
3480 Mikael Ronstrom 2009-08-05
Bug#32115, fixed review comments
3481 Mikael Ronstrom 2009-08-07
Bug#32115, remove now obsolete lex_start calls
Until-pos guarding did not distiguish the master originated events from ones that the slave
can introduce to the relay log e.g Rotate to the next relay log at slave restarting.
The local Rotate's coordinate are incomparable with the Until-master-pos.
That led to the unexpectable stop this bug describes.
Fixed with to avoid Until-master-pos comparison for a local slave's event.
Notice that if --replicate-same-server is true such event is treated as coming from
the master side.
mysql-test/r/rpl_until.result:
results changed.
mysql-test/t/rpl_until.test:
regression test for bug#47210 is added.
sql/slave.cc:
st_relay_log_info::is_until_satisfied() is augmented with avoidance of
Until-master-pos comparison for a local slave's event.
if --replicate-same-server is true such event is treated as coming from
the master side.
sql/slave.h:
signature of is_until_satisfied() changed to supply THD and Event to the routine.
Conflicts
=========
Text conflict in .bzr-mysql/default.conf
Text conflict in libmysqld/CMakeLists.txt
Text conflict in libmysqld/Makefile.am
Text conflict in mysql-test/collections/default.experimental
Text conflict in mysql-test/extra/rpl_tests/rpl_row_sp006.test
Text conflict in mysql-test/suite/binlog/r/binlog_tmp_table.result
Text conflict in mysql-test/suite/rpl/r/rpl_loaddata.result
Text conflict in mysql-test/suite/rpl/r/rpl_loaddata_fatal.result
Text conflict in mysql-test/suite/rpl/r/rpl_row_create_table.result
Text conflict in mysql-test/suite/rpl/r/rpl_row_sp006_InnoDB.result
Text conflict in mysql-test/suite/rpl/r/rpl_stm_log.result
Text conflict in mysql-test/suite/rpl_ndb/r/rpl_ndb_circular_simplex.result
Text conflict in mysql-test/suite/rpl_ndb/r/rpl_ndb_sp006.result
Text conflict in mysql-test/t/mysqlbinlog.test
Text conflict in sql/CMakeLists.txt
Text conflict in sql/Makefile.am
Text conflict in sql/log_event_old.cc
Text conflict in sql/rpl_rli.cc
Text conflict in sql/slave.cc
Text conflict in sql/sql_binlog.cc
Text conflict in sql/sql_lex.h
21 conflicts encountered.
NOTE
====
mysql-5.1-rpl-merge has been made a mirror of mysql-next-mr:
- "mysql-5.1-rpl-merge$ bzr pull ../mysql-next-mr"
This is the first cset (merge/...) committed after pulling
from mysql-next-mr.
2630.39.1, 2630.28.29, 2630.34.3, 2630.34.2, 2630.34.1, 2630.29.29,
2630.29.28, 2630.31.1, 2630.28.13, 2630.28.10, 2617.23.14 and
some other minor revisions.
This patch implements:
WL#4264 "Backup: Stabilize Service Interface" -- all the
server prerequisites except si_objects.{h,cc} themselves (they can
be just copied over, when needed).
WL#4435: Support OUT-parameters in prepared statements.
(and all issues in the initial patches for these two
tasks, that were discovered in pushbuild and during testing).
Bug#39519: mysql_stmt_close() should flush all data
associated with the statement.
After execution of a prepared statement, send OUT parameters of the invoked
stored procedure, if any, to the client.
When using the binary protocol, send the parameters in an additional result
set over the wire. When using the text protocol, assign out parameters to
the user variables from the CALL(@var1, @var2, ...) specification.
The following refactoring has been made:
- Protocol::send_fields() was renamed to Protocol::send_result_set_metadata();
- A new Protocol::send_result_set_row() was introduced to incapsulate
common functionality for sending row data.
- Signature of Protocol::prepare_for_send() was changed: this operation
does not need a list of items, the number of items is fully sufficient.
The following backward incompatible changes have been made:
- CLIENT_MULTI_RESULTS is now enabled by default in the client;
- CLIENT_PS_MULTI_RESUTLS is now enabled by default in the client.
include/mysql.h:
Add a new flag to MYSQL_METHODS::flush_use_result
function pointer. This flag determines if all results
should be flushed or only the first one:
- if flush_all_results is TRUE, then cli_flush_use_result()
will read/flush all pending results. I.e. it will read
all packets while server status attribute indicates that
there are more results. This is a new semantic, required
to fix the bug.
- if flush_all_results is FALSE, the old sematic
is preserved -- i.e. cli_flush_use_result() reads data
until first EOF-packet.
include/mysql.h.pp:
Update the ABI with new calls (compatible changes).
include/mysql_com.h:
Add CLIENT_PS_OUT_PARAMS -- a client capability indicating that the client supportsю
libmysql/libmysql.c:
Add mysql_stmt_next_result() -- analogue of mysql_next_result() for binary protocol.
Fix a minor bug in alloc_fields() -- not all members were copied over,
and some only shallow-copied (catalog).
Flush all results in mysql_stmt_close() (Bug#39519).
libmysqld/lib_sql.cc:
Rename send_fields() -> send_result_set_metadata().
Refactoring: change prepare_for_send() so that it accepts only
what it really needs -- a number of elements in the list.
mysql-test/r/ps.result:
Update results: WL#4435.
mysql-test/t/ps.test:
WL#4435: A test case for an SQL-part of the problem.
sql-common/client.c:
Bug#39519.
Implement new functionality in cli_flush_use_result():
if flush_all_delete is TRUE, then it should read/flush
all pending results.
sql/Makefile.am:
Add a new header sql_prepare.h to the list
of build headers.
sql/events.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/handler.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/mysql_priv.h:
Move sql_prepare.cc-specific declarations to a new
header - sql_prepare.h.
sql/procedure.h:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/protocol.cc:
Move the logic responsible for sending of one result
set row to the Protocol class. Define a template
for end-of-statement action.
Refactoring: change prepare_for_send() so that it accepts
only what it really needs -- a number of elements in the list.
Rename send_fields() to send_result_set_metadata().
sql/protocol.h:
Update with new declarations (WL#4435).
Rename send_fields() -> send_result_set_metadata().
prepare_for_send() only needs the number of columns to send,
and doesn't use the item list - update signature to require
only what's needed.
Add a new protocol type -- Protocol_local.
sql/repl_failsafe.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/slave.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_acl.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_base.cc:
Include sql_prepare.h (for Reprepare_observer).
sql/sql_cache.cc:
Extend the query cache flags block to be able
to store a numeric id for the result format,
not just a flag binary/non-binary.
sql/sql_class.cc:
Update to use the rename of Protocol::send_fields()
to Protocol::send_result_set_metadata().
Use Protocol::send_one_result_set_row().
sql/sql_class.h:
Move the declaration of Reprepare_observer to the
new header - sql_prepare.h.
Update to the new signature of class Protocol::send_fields().
sql/sql_connect.cc:
Use a protocol template method instead of
raw NET layer API at the end of a statement.
sql/sql_cursor.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_error.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_handler.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
Use new method Protocol::send_one_result_set_row().
sql/sql_help.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_lex.cc:
Initialize multi_statements variable.
Add a handy constant for empty lex
string.
sql/sql_lex.h:
Add a separate member for a standalone
parsing option - multi-statements support.
sql/sql_list.cc:
sql_list.h is a standalone header now,
no need to include mysql_priv.h.
sql/sql_list.h:
Make sql_list.h a stand-alone header.
sql/sql_parse.cc:
Include sql_prepare.h for prepared
statements- related declarations.
Use a new Protocol template method to end
each statement (send OK, EOF or ERROR to
the client).
sql/sql_prepare.cc:
Implement Execute Direct API (WL#4264),
currently unused. It will be used by the service
interface (Backup).
Use a new header - sql_prepare.h.
Add support for OUT parameters in the
binary and text protocol (prepared statements
only).
sql/sql_prepare.h:
Add a new header to contain (for now)
all prepared statement- external
related declarations.
sql/sql_profile.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_repl.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_select.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_show.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_string.h:
Add a way to convert a String to LEX_STRING.
sql/sql_table.cc:
Rename: Protocol::send_fields() ->
Protocol::send_result_set_metadata().
sql/sql_update.cc:
Remove an extraneous my_error(). The error
is already reported in update_non_unique_table_error().
sql/sql_yacc.yy:
Support for multi-statements is an independent
property of parsing, not derived from
the protocol type.
tests/mysql_client_test.c:
Add tests for WL#4435 (binary protocol).
Before the patch, slaves only appear in the output of SHOW SLAVE HOSTS
when report-host option is set. If an expected slave does not appear in
the list, nobody knows whether the slave does not connect or has started
without the "report-host" option. The output also contains a strange
field "Rpl_recovery_rank" which has never been implemented and the manual
of MySQL5.4 declares that the field has been removed from MySQL5.4.
This patch is done with these,
According to the manual of MySQL5.4, "Rpl_recovery_rank" is removed.
Slaves will register themselves to master no matter if report_host option is set
or not. When slaves are registering themselves, their Server_ids, report_host
and other information are together sent to master. Sever_ids are never null
and is unique in one replication group. Slaves always can be identified with
different Server_ids no matter if report_host exists.
Implemented the server infrastructure for the fix:
1. Added a function LEX_STRING *thd_query_string(THD) to return
a LEX_STRING structure instead of char *.
This is the function that must be called in innodb instead of
thd_query()
2. Did some encapsulation in THD : aggregated thd_query and
thd_query_length into a LEX_STRING and made accessor and mutator
methods for easy code updating.
3. Updated the server code to use the new methods where applicable.
The BINLOG statement was sharing too much code with the slave SQL thread, introduced with
the patch for Bug#32407. This caused statements to be logged with the wrong server_id, the
id stored inside the events of the BINLOG statement rather than the id of the running
server.
Fix by rearranging code a bit so that only relevant parts of the code are executed by
the BINLOG statement, and the server_id of the server executing the statements will
not be overrided by the server_id stored in the 'format description BINLOG statement'.
mysql-test/extra/binlog_tests/binlog.test:
Added test to verify if the server_id stored in the 'format
description BINLOG statement' will override the server_id
of the server executing the statements.
mysql-test/suite/binlog/r/binlog_row_binlog.result:
Test result for bug#46640
mysql-test/suite/binlog/r/binlog_stm_binlog.result:
Test result for bug#46640
sql/log_event.cc:
Moved rows_event_stmt_clean() call from update_pos() to apply_event(). This in any case
makes more sense, and is needed as update_pos() is no longer called when executing
BINLOG statements.
Moved setting of rli->relay_log.description_event_for_exec from
Format_description_log_event::do_update_pos() to
Format_description_log_event::do_apply_event()
sql/log_event_old.cc:
Moved rows_event_stmt_clean() call from update_pos() to apply_event(). This in any case
makes more sense, and is needed as update_pos() is no longer called when executing
BINLOG statements.
sql/slave.cc:
The skip flag is no longer needed, as the code path for BINLOG statement has been
cleaned up.
sql/sql_binlog.cc:
Don't invoke the update_pos() code path for the BINLOG statement, as it contains code
that is redundant and/or harmful (especially setting thd->server_id).
mysql-test/suite/rpl/r/rpl_stop_middle_group.result:
the new result file
mysql-test/suite/rpl/t/rpl_stop_middle_group.test:
renamed from rpl_row_stop_middle_update and added a regression test for bug#45940.
There are three internal status for slave I/O thread, both
MYSQL_SLAVE_RUN_NOT_CONNECT and MYSQL_SLAVE_NOT_RUN are reported
as 'No' for Slave_IO_running of command SHOW SLAVE STATUS.
Change MYSQL_SLAVE_RUN_NOT_CONNECT to be reported as 'Connecting'.
NOTE: Backporting the patch to next-mr.
The slave was crashing while failing to execute the init_slave() function.
The issue stems from two different reasons:
1 - A failure while allocating the master info structure generated a
segfault due to a NULL pointer.
2 - A failure while recovering generated a segfault due to a non-initialized
relay log file. In other words, the mi->init and rli->init were both set to true
before executing the recovery process thus creating an inconsistent state as the
relay log file was not initialized.
To circumvent such problems, we refactored the recovery process which is now executed
while initializing the relay log. It is ensured that the master info structure is
created before accessing it and any error is propagated thus avoiding to set mi->init
and rli->init to true when for instance the relay log is not initialized or the relay
info is not flushed.
The changes related to the refactory are described below:
1 - Removed call to init_recovery from init_slave.
2 - Changed the signature of the function init_recovery.
3 - Removed flushes. They are called while initializing the relay log and master
info.
4 - Made sure that if the relay info is not flushed the mi-init and rli-init are not
set to true.
In this patch, we also replaced the exit(1) in the fault injection by DBUG_ABORT()
to make it compliant with the code guidelines.
