- Changed ER(ER_...) to ER_THD(thd, ER_...) when thd was known or if there was many calls to current_thd in the same function.
- Changed ER(ER_..) to ER_THD_OR_DEFAULT(current_thd, ER...) in some places where current_thd is not necessary defined.
- Removing calls to current_thd when we have access to thd
Part of this is optimization (not calling current_thd when not needed),
but part is bug fixing for error condition when current_thd is not defined
(For example on startup and end of mysqld)
Notable renames done as otherwise a lot of functions would have to be changed:
- In JOIN structure renamed:
examined_rows -> join_examined_rows
record_count -> join_record_count
- In Field, renamed new_field() to make_new_field()
Other things:
- Added DBUG_ASSERT(thd == tmp_thd) in Item_singlerow_subselect() just to be safe.
- Removed old 'tab' prefix in JOIN_TAB::save_explain_data() and use members directly
- Added 'thd' as argument to a few functions to avoid calling current_thd.
Initialize abs_timeout when it is about to be used. This saves one my_hrtime()
call on hot path (when we acquire MDL lock without waiting).
When filling I_S.PROCESSLIST use THD::start_utime/THD::utime_after_query instead
of THD::start_time. This allows us to save 2 clock_gettime() calls.
Overhead change:
__clock_gettime 0.13% -> 0.11% (122 -> 76 calls per OLTP RO transaction)
my_interval_timer 0.07% -> 0.06%
my_hrtime 0.04% -> 0.01%
C++03 seem to require default constructor for const objects even though they're
fully initialized. There is defect report for this:
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#253
Apparently some compilers (e.g. gcc) addressed this defect report, while some
(e.g. clang) did not.
Added empty default constructor to MDL_scoped_lock and MDL_object_lock classes.
Also replaced lf_hash_search_using_hash_value() with lf_hash_search(). The
latter will call mdl_key->hash_value() anyway.
Simplified MDL_object_lock and MDL_scoped_lock dichotomy so that they can be
stored in LF_HASH. This was done by moving out their differences to a
MDL_lock_strategy structure which is referenced from the MDL_lock object by
pointer.
Replaced m_ref_usage, m_ref_release, m_is_destroyed and m_version with single
m_state, which is updated atomically. Needed to get rid of MDL_map::m_mutex.
Fix MDL to report an error when a wait was killed, but preserve
the old documented behavior of GET_LOCK() where killing it is not an error.
Also remove race conditions in main.create_or_replace test
Merged lp:maria/maria-10.0-galera up to revision 3879.
Added a new functions to handler API to forcefully abort_transaction,
producing fake_trx_id, get_checkpoint and set_checkpoint for XA. These
were added for future possiblity to add more storage engines that
could use galera replication.
I_S table
mdl_iterate() helper function (which is used by the plugin to iterate mdl
locks) acquired mutexes in reverse order.
Fixed by iterating MDL locks in two stages:
1. Iterate locks hash under the protection of hash mutex, store all
lock pointers in a thread local array and increment reference counter
for the lock.
2. Iterate local array without protection of hash mutex, handle destroyed
locks.
It somewhat echoes hack in MDL_map_partition::move_from_hash_to_lock_mutex.
Let TABLE_SHARE::tdc.free_tables, TABLE_SHARE::tdc.all_tables,
TABLE_SHARE::tdc.flushed and corresponding invariants be protected by
per-share TABLE_SHARE::tdc.LOCK_table_share instead of global LOCK_open.
Reduced number of my_hash_sort_bin() calls from 4 to 1 per query.
Reduced number of memory accesses done by my_hash_sort_bin().
Details:
- let MDL subsystem use pre-calculated hash value for hash
inserts and deletes
- let table cache use pre-calculated MDL hash value
- MDL namespace is excluded from hash value calculation, so that
hash value can be used by table cache as is
- hash value for MDL is calculated as resulting hash value + MDL
namespace
- extended hash implementation to accept user defined hash function
includes:
* remove some remnants of "Bug#14521864: MYSQL 5.1 TO 5.5 BUGS PARTITIONING"
* introduce LOCK_share, now LOCK_ha_data is strictly for engines
* rea_create_table() always creates .par file (even in "frm-only" mode)
* fix a 5.6 bug, temp file leak on dummy ALTER TABLE
mysql-test/r/mdl_sync.result:
Full merge with 5.6
mysql-test/t/mdl_sync.test:
Full merge with 5.6
sql/debug_sync.cc:
Full merge with 5.6
sql/debug_sync.h:
Full merge with 5.6
sql/mdl.cc:
Full merge with 5.6
sql/sql_base.cc:
Removed code not in 5.6 anymore
- Don't abort InnoDB if one can't allocate resources for AIO
(this patch was in 5.5 and 10.0-base but was missing in 10.0)
sql/mdl.cc:
Fixed compiler warning
storage/innobase/os/os0file.cc:
Don't abort InnoDB if one can't allocate resources for AIO
The patch contributed by Konstantin Osipov applied.
Native comments:
Implement multiple user-level locks per connection.
GET_LOCK() function in MySQL allows a connection to hold at most
one user level lock. Taking a new lock automatically releases the
old lock, if any.
The limit of one lock per session existed since early versions
of MySQL didn't have a deadlock detector for SQL locks.
MDL patches in MySQL 5.5 added a deadlock detector,
so starting from 5.5 it became possible to take multiple locks
in any order -- a deadlock, should it occur, would be detected
and an error returned to the client which closed the wait chain.
This is exactly what is done in this patch: ULLs are moved
to use MDL subsystem.
Base code and idea from a patch from by plinux at Taobao.
The idea is that we mark all memory that are thread specific with MY_THREAD_SPECIFIC.
Memory counting is done per thread in the my_malloc_size_cb_func callback function from my_malloc().
There are plenty of new asserts to ensure that for a debug server the counting is correct.
Information_schema.processlist gets two new columns: MEMORY_USED and EXAMINED_ROWS.
- The later is there mainly to show how query is progressing.
The following changes in interfaces was needed to get this to work:
- init_alloc_root() amd init_sql_alloc() has extra option so that one can mark memory with MY_THREAD_SPECIFIC
- One now have to use alloc_root_set_min_malloc() to set min memory to be allocated by alloc_root()
- my_init_dynamic_array() has extra option so that one can mark memory with MY_THREAD_SPECIFIC
- my_net_init() has extra option so that one can mark memory with MY_THREAD_SPECIFIC
- Added flag for hash_init() so that one can mark hash table to be thread specific.
- Added flags to init_tree() so that one can mark tree to be thread specific.
- Removed with_delete option to init_tree(). Now one should instead use MY_TREE_WITH_DELETE_FLAG.
- Added flag to Warning_info::Warning_info() if the structure should be fully initialized.
- String elements can now be marked as thread specific.
- Internal HEAP tables are now marking it's memory as MY_THREAD_SPECIFIC.
- Changed type of myf from int to ulong, as this is always a set of bit flags.
Other things:
- Removed calls to net_end() and thd->cleanup() as these are now done in ~THD()
- We now also show EXAMINED_ROWS in SHOW PROCESSLIST
- Added new variable 'memory_used'
- Fixed bug where kill_threads_for_user() was using the wrong mem_root to allocate memory.
- Removed calls to the obsoleted function init_dynamic_array()
- Use set_current_thd() instead of my_pthread_setspecific_ptr(THR_THD,...)
client/completion_hash.cc:
Updated call to init_alloc_root()
client/mysql.cc:
Updated call to init_alloc_root()
client/mysqlbinlog.cc:
init_dynamic_array() -> my_init_dynamic_array()
Updated call to init_alloc_root()
client/mysqlcheck.c:
Updated call to my_init_dynamic_array()
client/mysqldump.c:
Updated call to init_alloc_root()
client/mysqltest.cc:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
Fixed compiler warnings
extra/comp_err.c:
Updated call to my_init_dynamic_array()
extra/resolve_stack_dump.c:
Updated call to my_init_dynamic_array()
include/hash.h:
Added HASH_THREAD_SPECIFIC
include/heap.h:
Added flag is internal temporary table.
include/my_dir.h:
Safety fix: Ensure that MY_DONT_SORT and MY_WANT_STAT don't interfer with other mysys flags
include/my_global.h:
Changed type of myf from int to ulong, as this is always a set of bit flags.
include/my_sys.h:
Added MY_THREAD_SPECIFIC and MY_THREAD_MOVE
Added malloc_flags to DYNAMIC_ARRAY
Added extra mysys flag argument to my_init_dynamic_array()
Removed deprecated functions init_dynamic_array() and my_init_dynamic_array.._ci
Updated paramaters for init_alloc_root()
include/my_tree.h:
Added my_flags to allow one to use MY_THREAD_SPECIFIC with hash tables.
Removed with_delete. One should now instead use MY_TREE_WITH_DELETE_FLAG
Updated parameters to init_tree()
include/myisamchk.h:
Added malloc_flags to allow one to use MY_THREAD_SPECIFIC for checks.
include/mysql.h:
Added MYSQL_THREAD_SPECIFIC_MALLOC
Used 'unused1' to mark memory as thread specific.
include/mysql.h.pp:
Updated file
include/mysql_com.h:
Used 'unused1' to mark memory as thread specific.
Updated parameters for my_net_init()
libmysql/libmysql.c:
Updated call to init_alloc_root() to mark memory thread specific.
libmysqld/emb_qcache.cc:
Updated call to init_alloc_root()
libmysqld/lib_sql.cc:
Updated call to init_alloc_root()
mysql-test/r/create.result:
Updated results
mysql-test/r/user_var.result:
Updated results
mysql-test/suite/funcs_1/datadict/processlist_priv.inc:
Update to handle new format of SHOW PROCESSLIST
mysql-test/suite/funcs_1/datadict/processlist_val.inc:
Update to handle new format of SHOW PROCESSLIST
mysql-test/suite/funcs_1/r/is_columns_is.result:
Update to handle new format of SHOW PROCESSLIST
mysql-test/suite/funcs_1/r/processlist_priv_no_prot.result:
Updated results
mysql-test/suite/funcs_1/r/processlist_val_no_prot.result:
Updated results
mysql-test/t/show_explain.test:
Fixed usage of debug variable so that one can run test with --debug
mysql-test/t/user_var.test:
Added test of memory_usage variable.
mysys/array.c:
Added extra my_flags option to init_dynamic_array() and init_dynamic_array2() so that one can mark memory with MY_THREAD_SPECIFIC
All allocated memory is marked with the given my_flags.
Removed obsolete function init_dynamic_array()
mysys/default.c:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
mysys/hash.c:
Updated call to my_init_dynamic_array_ci().
Allocated memory is marked with MY_THREAD_SPECIFIC if HASH_THREAD_SPECIFIC is used.
mysys/ma_dyncol.c:
init_dynamic_array() -> my_init_dynamic_array()
Added #if to get rid of compiler warnings
mysys/mf_tempdir.c:
Updated call to my_init_dynamic_array()
mysys/my_alloc.c:
Added extra parameter to init_alloc_root() so that one can mark memory with MY_THREAD_SPECIFIC
Extend MEM_ROOT with a flag if memory is thread specific.
This is stored in block_size, to keep the size of the MEM_ROOT object identical as before.
Allocated memory is marked with MY_THREAD_SPECIFIC if used with init_alloc_root()
mysys/my_chmod.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_chsize.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_copy.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_create.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_delete.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_error.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_fopen.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_fstream.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_getwd.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_lib.c:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
Updated DBUG_PRINT because of change of myf type
mysys/my_lock.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_malloc.c:
Store at start of each allocated memory block the size of the block and if the block is thread specific.
Call malloc_size_cb_func, if set, with the memory allocated/freed.
Updated DBUG_PRINT because of change of myf type
mysys/my_open.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_pread.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_read.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_redel.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_rename.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_seek.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_sync.c:
Updated DBUG_PRINT because of change of myf type
mysys/my_thr_init.c:
Ensure that one can call my_thread_dbug_id() even if thread is not properly initialized.
mysys/my_write.c:
Updated DBUG_PRINT because of change of myf type
mysys/mysys_priv.h:
Updated parameters to sf_malloc and sf_realloc()
mysys/safemalloc.c:
Added checking that for memory marked with MY_THREAD_SPECIFIC that it's the same thread that is allocation and freeing the memory.
Added sf_malloc_dbug_id() to allow MariaDB to specify which THD is handling the memory.
Added my_flags arguments to sf_malloc() and sf_realloc() to be able to mark memory with MY_THREAD_SPECIFIC.
Added sf_report_leaked_memory() to get list of memory not freed by a thread.
mysys/tree.c:
Added flags to init_tree() so that one can mark tree to be thread specific.
Removed with_delete option to init_tree(). Now one should instead use MY_TREE_WITH_DELETE_FLAG.
Updated call to init_alloc_root()
All allocated memory is marked with the given malloc flags
mysys/waiting_threads.c:
Updated call to my_init_dynamic_array()
sql-common/client.c:
Updated call to init_alloc_root() and my_net_init() to mark memory thread specific.
Updated call to my_init_dynamic_array().
Added MYSQL_THREAD_SPECIFIC_MALLOC so that client can mark memory as MY_THREAD_SPECIFIC.
sql-common/client_plugin.c:
Updated call to init_alloc_root()
sql/debug_sync.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/event_scheduler.cc:
Removed calls to net_end() as this is now done in ~THD()
Call set_current_thd() to ensure that memory is assigned to right thread.
sql/events.cc:
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/filesort.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/filesort_utils.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/ha_ndbcluster.cc:
Updated call to init_alloc_root()
Updated call to my_net_init()
Removed calls to net_end() and thd->cleanup() as these are now done in ~THD()
sql/ha_ndbcluster_binlog.cc:
Updated call to my_net_init()
Updated call to init_sql_alloc()
Removed calls to net_end() and thd->cleanup() as these are now done in ~THD()
sql/ha_partition.cc:
Updated call to init_alloc_root()
sql/handler.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
Added missing call to my_dir_end()
sql/item_func.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/item_subselect.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/item_sum.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/log.cc:
More DBUG
Updated call to init_alloc_root()
sql/mdl.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/mysqld.cc:
Added total_memory_used
Updated call to init_alloc_root()
Move mysql_cond_broadcast() before my_thread_end()
Added mariadb_dbug_id() to count memory per THD instead of per thread.
Added my_malloc_size_cb_func() callback function for my_malloc() to count memory.
Move initialization of mysqld_server_started and mysqld_server_initialized earlier.
Updated call to my_init_dynamic_array().
Updated call to my_net_init().
Call my_pthread_setspecific_ptr(THR_THD,...) to ensure that memory is assigned to right thread.
Added status variable 'memory_used'.
Updated call to init_alloc_root()
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/mysqld.h:
Added set_current_thd()
sql/net_serv.cc:
Added new parameter to my_net_init() so that one can mark memory with MY_THREAD_SPECIFIC.
Store in net->thread_specific_malloc if memory is thread specific.
Mark memory to be thread specific if requested.
sql/opt_range.cc:
Updated call to my_init_dynamic_array()
Updated call to init_sql_alloc()
Added MY_THREAD_SPECIFIC to allocated memory.
sql/opt_subselect.cc:
Updated call to init_sql_alloc() to mark memory thread specific.
sql/protocol.cc:
Fixed compiler warning
sql/records.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/rpl_filter.cc:
Updated call to my_init_dynamic_array()
sql/rpl_handler.cc:
Updated call to my_init_dynamic_array2()
sql/rpl_handler.h:
Updated call to init_sql_alloc()
sql/rpl_mi.cc:
Updated call to my_init_dynamic_array()
sql/rpl_tblmap.cc:
Updated call to init_alloc_root()
sql/rpl_utility.cc:
Updated call to my_init_dynamic_array()
sql/slave.cc:
Initialize things properly before calling functions that allocate memory.
Removed calls to net_end() as this is now done in ~THD()
sql/sp_head.cc:
Updated call to init_sql_alloc()
Updated call to my_init_dynamic_array()
Added parameter to warning_info() that it should be fully initialized.
sql/sp_pcontext.cc:
Updated call to my_init_dynamic_array()
sql/sql_acl.cc:
Updated call to init_sql_alloc()
Updated call to my_init_dynamic_array()
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_admin.cc:
Added parameter to warning_info() that it should be fully initialized.
sql/sql_analyse.h:
Updated call to init_tree() to mark memory thread specific.
sql/sql_array.h:
Updated call to my_init_dynamic_array() to mark memory thread specific.
sql/sql_audit.cc:
Updated call to my_init_dynamic_array()
sql/sql_base.cc:
Updated call to init_sql_alloc()
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_cache.cc:
Updated comment
sql/sql_class.cc:
Added parameter to warning_info() that not initialize it until THD is fully created.
Updated call to init_sql_alloc()
Mark THD::user_vars has to be thread specific.
Updated call to my_init_dynamic_array()
Ensure that memory allocated by THD is assigned to the THD.
More DBUG
Always acll net_end() in ~THD()
Assert that all memory signed to this THD is really deleted at ~THD.
Fixed set_status_var_init() to not reset memory_used.
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_class.h:
Added MY_THREAD_SPECIFIC to allocated memory.
Added malloc_size to THD to record allocated memory per THD.
sql/sql_delete.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/sql_error.cc:
Added 'initialize' parameter to Warning_info() to say if should allocate memory for it's structures.
This is used by THD::THD() to not allocate memory until THD is ready.
Added Warning_info::free_memory()
sql/sql_error.h:
Updated Warning_info() class.
sql/sql_handler.cc:
Updated call to init_alloc_root() to mark memory thread specific.
sql/sql_insert.cc:
More DBUG
sql/sql_join_cache.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/sql_lex.cc:
Updated call to my_init_dynamic_array()
sql/sql_lex.h:
Updated call to my_init_dynamic_array()
sql/sql_load.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/sql_parse.cc:
Removed calls to net_end() and thd->cleanup() as these are now done in ~THD()
Ensure that examined_row_count() is reset before query.
Fixed bug where kill_threads_for_user() was using the wrong mem_root to allocate memory.
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
Don't restore thd->status_var.memory_used when restoring thd->status_var
sql/sql_plugin.cc:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
Don't allocate THD on the stack, as this causes problems with valgrind when doing thd memory counting.
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_prepare.cc:
Added parameter to warning_info() that it should be fully initialized.
Updated call to init_sql_alloc() to mark memory thread specific.
sql/sql_reload.cc:
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_select.cc:
Updated call to my_init_dynamic_array() and init_sql_alloc() to mark memory thread specific.
Added MY_THREAD_SPECIFIC to allocated memory.
More DBUG
sql/sql_servers.cc:
Updated call to init_sql_alloc() to mark memory some memory thread specific.
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_show.cc:
Updated call to my_init_dynamic_array()
Mark my_dir() memory thread specific.
Use my_pthread_setspecific_ptr(THR_THD,...) to mark that allocated memory should be allocated to calling thread.
More DBUG.
Added malloc_size and examined_row_count to SHOW PROCESSLIST.
Added MY_THREAD_SPECIFIC to allocated memory.
Updated call to init_sql_alloc()
Added parameter to warning_info() that it should be fully initialized.
sql/sql_statistics.cc:
Fixed compiler warning
sql/sql_string.cc:
String elements can now be marked as thread specific.
sql/sql_string.h:
String elements can now be marked as thread specific.
sql/sql_table.cc:
Updated call to init_sql_alloc() and my_malloc() to mark memory thread specific
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
Fixed compiler warning
sql/sql_test.cc:
Updated call to my_init_dynamic_array() to mark memory thread specific.
sql/sql_trigger.cc:
Updated call to init_sql_alloc()
sql/sql_udf.cc:
Updated call to init_sql_alloc()
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/sql_update.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
sql/table.cc:
Updated call to init_sql_alloc().
Mark memory used by temporary tables, that are not for slave threads, as MY_THREAD_SPECIFIC
Updated call to init_sql_alloc()
sql/thr_malloc.cc:
Added my_flags argument to init_sql_alloc() to be able to mark memory as MY_THREAD_SPECIFIC.
sql/thr_malloc.h:
Updated prototype for init_sql_alloc()
sql/tztime.cc:
Updated call to init_sql_alloc()
Updated call to init_alloc_root() to mark memory thread specific.
my_pthread_setspecific_ptr(THR_THD,...) -> set_current_thd()
sql/uniques.cc:
Updated calls to init_tree(), my_init_dynamic_array() and my_malloc() to mark memory thread specific.
sql/unireg.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
storage/csv/ha_tina.cc:
Updated call to init_alloc_root()
storage/federated/ha_federated.cc:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
Ensure that memory allocated by fedarated is registered for the system, not for the thread.
storage/federatedx/federatedx_io_mysql.cc:
Updated call to my_init_dynamic_array()
storage/federatedx/ha_federatedx.cc:
Updated call to init_alloc_root()
Updated call to my_init_dynamic_array()
storage/heap/ha_heap.cc:
Added MY_THREAD_SPECIFIC to allocated memory.
storage/heap/heapdef.h:
Added parameter to hp_get_new_block() to be able to do thread specific memory tagging.
storage/heap/hp_block.c:
Added parameter to hp_get_new_block() to be able to do thread specific memory tagging.
storage/heap/hp_create.c:
- Internal HEAP tables are now marking it's memory as MY_THREAD_SPECIFIC.
- Use MY_TREE_WITH_DELETE instead of removed option 'with_delete'.
storage/heap/hp_open.c:
Internal HEAP tables are now marking it's memory as MY_THREAD_SPECIFIC.
storage/heap/hp_write.c:
Added new parameter to hp_get_new_block()
storage/maria/ma_bitmap.c:
Updated call to my_init_dynamic_array()
storage/maria/ma_blockrec.c:
Updated call to my_init_dynamic_array()
storage/maria/ma_check.c:
Updated call to init_alloc_root()
storage/maria/ma_ft_boolean_search.c:
Updated calls to init_tree() and init_alloc_root()
storage/maria/ma_ft_nlq_search.c:
Updated call to init_tree()
storage/maria/ma_ft_parser.c:
Updated call to init_tree()
Updated call to init_alloc_root()
storage/maria/ma_loghandler.c:
Updated call to my_init_dynamic_array()
storage/maria/ma_open.c:
Updated call to my_init_dynamic_array()
storage/maria/ma_sort.c:
Updated call to my_init_dynamic_array()
storage/maria/ma_write.c:
Updated calls to my_init_dynamic_array() and init_tree()
storage/maria/maria_pack.c:
Updated call to init_tree()
storage/maria/unittest/sequence_storage.c:
Updated call to my_init_dynamic_array()
storage/myisam/ft_boolean_search.c:
Updated call to init_tree()
Updated call to init_alloc_root()
storage/myisam/ft_nlq_search.c:
Updated call to init_tree()
storage/myisam/ft_parser.c:
Updated call to init_tree()
Updated call to init_alloc_root()
storage/myisam/ft_stopwords.c:
Updated call to init_tree()
storage/myisam/mi_check.c:
Updated call to init_alloc_root()
storage/myisam/mi_write.c:
Updated call to my_init_dynamic_array()
Updated call to init_tree()
storage/myisam/myisamlog.c:
Updated call to init_tree()
storage/myisam/myisampack.c:
Updated call to init_tree()
storage/myisam/sort.c:
Updated call to my_init_dynamic_array()
storage/myisammrg/ha_myisammrg.cc:
Updated call to init_sql_alloc()
storage/perfschema/pfs_check.cc:
Rest current_thd
storage/perfschema/pfs_instr.cc:
Removed DBUG_ENTER/DBUG_VOID_RETURN as at this point my_thread_var is not allocated anymore, which can cause problems.
support-files/compiler_warnings.supp:
Disable compiler warning from offsetof macro.
KILL now breaks locks inside InnoDB
Fixed possible deadlock when running INNODB STATUS
Added ha_kill_query() and kill_query() to send kill signal to all storage engines
Added reset_killed() to ensure we don't reset killed state while awake() is getting called
include/mysql/plugin.h:
Added thd_mark_as_hard_kill()
include/mysql/plugin_audit.h.pp:
Added thd_mark_as_hard_kill()
include/mysql/plugin_auth.h.pp:
Added thd_mark_as_hard_kill()
include/mysql/plugin_ftparser.h.pp:
Added thd_mark_as_hard_kill()
sql/handler.cc:
Added ha_kill_query() to send kill signal to all storage engines
sql/handler.h:
Added ha_kill_query() and kill_query() to send kill signal to all storage engines
sql/log_event.cc:
Use reset_killed()
sql/mdl.cc:
use thd->killed instead of thd_killed() to abort on soft kill
sql/sp_rcontext.cc:
Use reset_killed()
sql/sql_class.cc:
Fixed possible deadlock in INNODB STATUS by not getting thd->LOCK_thd_data if it's locked.
Use reset_killed()
Tell storge engines that KILL has been sent
sql/sql_class.h:
Added reset_killed() to ensure we don't reset killed state while awake() is getting called.
Added mark_as_hard_kill()
sql/sql_insert.cc:
Use reset_killed()
sql/sql_parse.cc:
Simplify detection of killed queries.
Use reset_killed()
sql/sql_select.cc:
Use reset_killed()
sql/sql_union.cc:
Use reset_killed()
storage/innobase/handler/ha_innodb.cc:
Added innobase_kill_query()
Fixed error reporting for interrupted queries.
storage/xtradb/handler/ha_innodb.cc:
Added innobase_kill_query()
Fixed error reporting for interrupted queries.
- Fixed broadcast without a proper mutex
- Don't break existing locks if we are just testing if we can get the lock
mysql-test/r/create_delayed.result:
Added test case for failures with INSERT DELAYED with CREATE and DROP TABLE
mysql-test/t/create_delayed.test:
Added test case for failures with INSERT DELAYED with CREATE and DROP TABLE
sql/mdl.cc:
Don't break existing locks for timeout=0 (ie, just check if there are conflicting locks).
This fixed the bug that INSERT DELAYED didn't work properly with CREATE TABLE
sql/sql_base.cc:
One neads to hold the mutex before doing a mysql_cond_broadcast()
This fixed the bug that INSERT DELAYED didn't work properly with DROP TABLE
sql/sql_insert.cc:
Protect setting of mysys_var->current_mutex.
and small collateral changes
mysql-test/lib/My/Test.pm:
somehow with "print" we get truncated writes sometimes
mysql-test/suite/perfschema/r/digest_table_full.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/dml_handler.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/information_schema.result:
host table is not ported over yet
mysql-test/suite/perfschema/r/nesting.result:
this differs, because we don't rewrite general log queries, and multi-statement
packets are logged as a one entry. this result file is identical to what mysql-5.6.5
produces with the --log-raw option.
mysql-test/suite/perfschema/r/relaylog.result:
MariaDB modifies the binlog index file directly, while MySQL 5.6 has a feature "crash-safe binlog index" and modifies a special "crash-safe" shadow copy of the index file and then moves it over. That's why this test shows "NONE" index file writes in MySQL and "MANY" in MariaDB.
mysql-test/suite/perfschema/r/server_init.result:
MariaDB initializes the "manager" resources from the "manager" thread, and starts this thread only when --flush-time is not 0. MySQL 5.6 initializes "manager" resources unconditionally on server startup.
mysql-test/suite/perfschema/r/stage_mdl_global.result:
this differs, because MariaDB disables query cache when query_cache_size=0. MySQL does not
do that, and this causes useless mutex locks and waits.
mysql-test/suite/perfschema/r/statement_digest.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_consumers.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/perfschema/r/statement_digest_long_query.result:
md5 hashes of statement digests differ, because yacc token codes are different in mariadb
mysql-test/suite/rpl/r/rpl_mixed_drop_create_temp_table.result:
will be updated to match 5.6 when alfranio.correia@oracle.com-20110512172919-c1b5kmum4h52g0ni and anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y are merged
mysql-test/suite/rpl/r/rpl_non_direct_mixed_mixing_engines.result:
will be updated to match 5.6 when anders.song@greatopensource.com-20110105052107-zoab0bsf5a6xxk2y is merged
FOREVER MDL LOCK
Analysis:
----------
While granting MDL lock for the lock requests in wait queue,
first the lock is granted to the high priority lock types
and then to the low priority lock types.
MDL Priority Matrix,
+-------------+----+---+---+---+----+-----+
| Locks | | | | | | |
| has Priority| | | | | | |
| over ---> | S | SR| SW| SU| SNW| SNRW|
+-------------+----+---+---+---+----+-----+
| X | + | + | + | + | + | + |
+-------------|----|---|---|---|----|-----|
| SNRW | - | + | + | - | - | - |
+-------------|----|---|---|---|----|-----|
| SNW | - | - | + | - | - | - |
+-------------+----+---+---+---+----+-----+
Here '+' means, Lock priority is higher.
'-' means, Has same priority
In the scenario where,
*. Lock wait queue has requests of type S/SR/SW/SU.
*. And locks of high priority X/SNRW/SNW are requested
continuously.
In this case, while granting lock, always first high priority
lock requests(X/SNRW/SNW) are considered. Low priority
locks(S/SR/SW/SU) will not get chance and they will
wait forever.
In the scenario for which this bug is reported, application
executed many LOCK TABLES ... WRITE statements concurrently.
These statements request SNRW lock. Also there were some
connections trying to execute DML statements requesting SR
lock. Since SNRW lock request has higher priority (and as
they were too many waiting SNRW requests) lock is always
granted to it. So, lock request SR will wait forever, resulting
in DML starvation.
How is this handled in 5.1?
---------------------------
Even in 5.1 we have low priority lock starvation issue.
But, in 5.1 thread locking, system variable
"max_write_lock_count" can be configured to grant
some pending read lock requests. After
"max_write_lock_count" of write lock grants all the low
priority locks are granted.
Why this issue is seen in 5.5/trunk?
---------------------------------
In 5.5/trunk MDL locking, "max_write_lock_count" system
variable exists but not used in MDL, only thread lock uses
it. So no effect of "max_write_lock_count" in MDL locking.
This means that starvation of metadata locks is possible
even if max_write_lock_count is used.
Looks like, customer was using "max_write_lock_count" in
5.1 and when upgraded to 5.5, starvation is seen because
of not having effect of "max_write_lock_count" in MDL.
Fix:
----------
As a fix, support for max_write_lock_count is added to MDL.
To maintain write lock counter per MDL_lock object, new
member "m_hog_lock_count" is added in MDL_lock.
And following logic is added to increment the counter in
function reschedule_waiters,
(reschedule_waiters function is called while thread is
releasing the lock)
- After granting lock request from the wait queue.
- Check if there are any S/SR/SU/SW exists in the wait queue
- If yes then increment the "m_hog_lock_count"
And following logic is added in the same function to
handle pending S/SU/SR/SW locks
- Before granting locks
- Check if max_write_lock_count <= m_hog_lock_count
- If Yes, then try to grant S/SR/SW/SU locks.
(Since all of these has same priority, all locks are
granted together. But some lock grant may fail because
of grant incompatibility)
- Reset m_hog_lock_count if there no low priority lock
requests in wait queue.
- return
Note:
--------------------------
In the lock priority matrix explained above,
though X has priority over the SNW and SNRW. X locks is
taken mostly for RENAME, TRUNCATE, CREATE ... operations.
So lock type X may not be requested in loop continuously
in real world applications, as compared to other lock
request types. So, lock request of type SNW and SNRW are
not starved. So, we can grant all S/SR/SU/SW in one shot,
without considering SNW & SNRW lock request starvation.
ALTER table operations take SU lock first and then
upgrade to SNW if required. All S, SR, SW, SU have same
lock priority. So while granting SU, request of types
SR, SW, S are also granted in one shot. So, lock request
of type SU->SNW in loop will not make other low priority
lock request to starve.
But, when there is request for lock of type SNRW, lock
requests of lower priority types are not granted. And if
SNRW is requested in loop continuously then all
S, SR, SW, SU are starved.
This patch addresses the latter scenario.
When we have S/SR/SW/SU in wait queue and if
there are
- Continuous SNRW lock requests
- OR one or more X and Continuous SNRW lock requests.
- OR one SNW and Continuous SNRW lock requests.
- OR one SNW, one or more X and continuous SNRW lock
requests.
in wait queue then, S/SR/SW/SU lock request are starved.
BY CACHING OR REDUCING CREATEEVENT CALLS".
5.5 versions of MySQL server performed worse than 5.1 versions
under single-connection workload in autocommit mode on Windows XP.
Part of this slowdown can be attributed to overhead associated
with constant creation/destruction of MDL_lock objects in the MDL
subsystem. The problem is that creation/destruction of these
objects causes creation and destruction of associated
synchronization primitives, which are expensive on Windows XP.
This patch tries to alleviate this problem by introducing a cache
of unused MDL_object_lock objects. Instead of destroying such
objects we put them into the cache and then reuse with a new
key when creation of a new object is requested.
To limit the size of this cache, a new --metadata-locks-cache-size
start-up parameter was introduced.
mysql-test/r/mysqld--help-notwin.result:
Updated test after adding --metadata-locks-cache-size
parameter.
mysql-test/r/mysqld--help-win.result:
Updated test after adding --metadata-locks-cache-size
parameter.
mysql-test/suite/sys_vars/r/metadata_locks_cache_size_basic.result:
Added test coverage for newly introduced --metadata_locks_cache_size
start-up parameter and corresponding global read-only variable.
mysql-test/suite/sys_vars/t/metadata_locks_cache_size_basic-master.opt:
Added test coverage for newly introduced --metadata_locks_cache_size
start-up parameter and corresponding global read-only variable.
mysql-test/suite/sys_vars/t/metadata_locks_cache_size_basic.test:
Added test coverage for newly introduced --metadata_locks_cache_size
start-up parameter and corresponding global read-only variable.
sql/mdl.cc:
Introduced caching of unused MDL_object_lock objects, in order to
avoid costs associated with constant creation and destruction of
such objects in single-connection workloads run in autocommit mode.
Such costs can be pretty high on systems where creation and
destruction of synchronization primitives require a system call
(e.g. Windows XP).
To implement this cache,a list of unused MDL_object_lock instances
was added to MDL_map object. Instead of being destroyed
MDL_object_lock instances are put into this list and re-used later
when creation of a new instance is required. Also added
MDL_lock::m_version counter to allow threads having outstanding
references to an MDL_object_lock instance to notice that it has
been moved to the unused objects list.
Added a global variable for a start-up parameter that limits
the size of the unused objects list.
Note that we don't cache MDL_scoped_lock objects since they
are supposed to be created only during execution of DDL
statements and therefore should not affect performance much.
sql/mdl.h:
Added a global variable for start-up parameter that limits the
size of the unused MDL_object_lock objects list and constant
for its default value.
sql/sql_plist.h:
Added I_P_List<>::pop_front() function.
sql/sys_vars.cc:
Introduced --metadata-locks-cache-size start-up parameter
for specifying size of the cache of unused MDL_object_lock
objects.
bug #57006 "Deadlock between HANDLER and FLUSH TABLES WITH READ
LOCK" and bug #54673 "It takes too long to get readlock for
'FLUSH TABLES WITH READ LOCK'".
The first bug manifested itself as a deadlock which occurred
when a connection, which had some table open through HANDLER
statement, tried to update some data through DML statement
while another connection tried to execute FLUSH TABLES WITH
READ LOCK concurrently.
What happened was that FTWRL in the second connection managed
to perform first step of GRL acquisition and thus blocked all
upcoming DML. After that it started to wait for table open
through HANDLER statement to be flushed. When the first connection
tried to execute DML it has started to wait for GRL/the second
connection creating deadlock.
The second bug manifested itself as starvation of FLUSH TABLES
WITH READ LOCK statements in cases when there was a constant
stream of concurrent DML statements (in two or more
connections).
This has happened because requests for protection against GRL
which were acquired by DML statements were ignoring presence of
pending GRL and thus the latter was starved.
This patch solves both these problems by re-implementing GRL
using metadata locks.
Similar to the old implementation acquisition of GRL in new
implementation is two-step. During the first step we block
all concurrent DML and DDL statements by acquiring global S
metadata lock (each DML and DDL statement acquires global IX
lock for its duration). During the second step we block commits
by acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).
Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.
The first problem is solved because waits for GRL become
visible to deadlock detector in metadata locking subsystem
and thus deadlocks like one in the first bug become impossible.
The second problem is solved because global S locks which
are used for GRL implementation are given preference over
IX locks which are acquired by concurrent DML (and we can
switch to fair scheduling in future if needed).
Important change:
FTWRL/GRL no longer blocks DML and DDL on temporary tables.
Before this patch behavior was not consistent in this respect:
in some cases DML/DDL statements on temporary tables were
blocked while in others they were not. Since the main use cases
for FTWRL are various forms of backups and temporary tables are
not preserved during backups we have opted for consistently
allowing DML/DDL on temporary tables during FTWRL/GRL.
Important change:
This patch changes thread state names which are used when
DML/DDL of FTWRL is waiting for global read lock. It is now
either "Waiting for global read lock" or "Waiting for commit
lock" depending on the stage on which FTWRL is.
Incompatible change:
To solve deadlock in events code which was exposed by this
patch we have to replace LOCK_event_metadata mutex with
metadata locks on events. As result we have to prohibit
DDL on events under LOCK TABLES.
This patch also adds extensive test coverage for interaction
of DML/DDL and FTWRL.
Performance of new and old global read lock implementations
in sysbench tests were compared. There were no significant
difference between new and old implementations.
mysql-test/include/check_ftwrl_compatible.inc:
Added helper script which allows to check that a statement is
compatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/check_ftwrl_incompatible.inc:
Added helper script which allows to check that a statement is
incompatible with FLUSH TABLES WITH READ LOCK.
mysql-test/include/handler.inc:
Adjusted test case to the fact that now DROP TABLE closes
open HANDLERs for the table to be dropped before checking
if there active FTWRL in this connection.
mysql-test/include/wait_show_condition.inc:
Fixed small error in the timeout message. The correct name
of variable used as parameter for this script is "$condition"
and not "$wait_condition".
mysql-test/r/delayed.result:
Added test coverage for scenario which triggered assert in
metadata locking subsystem.
mysql-test/r/events_2.result:
Updated test results after prohibiting event DDL operations
under LOCK TABLES.
mysql-test/r/flush.result:
Added test coverage for bug #57006 "Deadlock between HANDLER
and FLUSH TABLES WITH READ LOCK".
mysql-test/r/flush_read_lock.result:
Added test coverage for various aspects of FLUSH TABLES WITH
READ LOCK functionality.
mysql-test/r/flush_read_lock_kill.result:
Adjusted test case after replacing custom global read lock
implementation with one based on metadata locks. Use new
debug_sync point. Do not disable concurrent inserts as now
InnoDB we always use InnoDB table.
mysql-test/r/handler_innodb.result:
Adjusted test case to the fact that now DROP TABLE closes
open HANDLERs for the table to be dropped before checking
if there active FTWRL in this connection.
mysql-test/r/handler_myisam.result:
Adjusted test case to the fact that now DROP TABLE closes
open HANDLERs for the table to be dropped before checking
if there active FTWRL in this connection.
mysql-test/r/mdl_sync.result:
Adjusted test case after replacing custom global read lock
implementation with one based on metadata locks. Replaced
usage of GRL-specific debug_sync's with appropriate sync
points in MDL subsystem.
mysql-test/suite/perfschema/r/dml_setup_instruments.result:
Updated test results after removing global
COND_global_read_lock condition variable.
mysql-test/suite/perfschema/r/func_file_io.result:
Ensure that this test doesn't affect subsequent tests.
At the end of its execution enable back P_S instrumentation
which this test disables at some point.
mysql-test/suite/perfschema/r/func_mutex.result:
Ensure that this test doesn't affect subsequent tests.
At the end of its execution enable back P_S instrumentation
which this test disables at some point.
mysql-test/suite/perfschema/r/global_read_lock.result:
Adjusted test case to take into account that new GRL
implementation is based on MDL.
mysql-test/suite/perfschema/r/server_init.result:
Adjusted test case after replacing custom global read
lock implementation with one based on MDL and replacing
LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/perfschema/t/func_file_io.test:
Ensure that this test doesn't affect subsequent tests.
At the end of its execution enable back P_S instrumentation
which this test disables at some point.
mysql-test/suite/perfschema/t/func_mutex.test:
Ensure that this test doesn't affect subsequent tests.
At the end of its execution enable back P_S instrumentation
which this test disables at some point.
mysql-test/suite/perfschema/t/global_read_lock.test:
Adjusted test case to take into account that new GRL
implementation is based on MDL.
mysql-test/suite/perfschema/t/server_init.test:
Adjusted test case after replacing custom global read
lock implementation with one based on MDL and replacing
LOCK_event_metadata mutex with metadata lock.
mysql-test/suite/rpl/r/rpl_tmp_table_and_DDL.result:
Updated test results after prohibiting event DDL under
LOCK TABLES.
mysql-test/t/delayed.test:
Added test coverage for scenario which triggered assert in
metadata locking subsystem.
mysql-test/t/events_2.test:
Updated test case after prohibiting event DDL operations
under LOCK TABLES.
mysql-test/t/flush.test:
Added test coverage for bug #57006 "Deadlock between HANDLER
and FLUSH TABLES WITH READ LOCK".
mysql-test/t/flush_block_commit.test:
Adjusted test case after changing thread state name which
is used when COMMIT waits for FLUSH TABLES WITH READ LOCK
from "Waiting for release of readlock" to "Waiting for commit
lock".
mysql-test/t/flush_block_commit_notembedded.test:
Adjusted test case after changing thread state name which is
used when DML waits for FLUSH TABLES WITH READ LOCK. Now we
use "Waiting for global read lock" in this case.
mysql-test/t/flush_read_lock.test:
Added test coverage for various aspects of FLUSH TABLES WITH
READ LOCK functionality.
mysql-test/t/flush_read_lock_kill-master.opt:
We no longer need to use make_global_read_lock_block_commit_loop
debug tag in this test. Instead we rely on an appropriate
debug_sync point in MDL code.
mysql-test/t/flush_read_lock_kill.test:
Adjusted test case after replacing custom global read lock
implementation with one based on metadata locks. Use new
debug_sync point. Do not disable concurrent inserts as now
InnoDB we always use InnoDB table.
mysql-test/t/lock_multi.test:
Adjusted test case after changing thread state names which
are used when DML or DDL waits for FLUSH TABLES WITH READ
LOCK to "Waiting for global read lock".
mysql-test/t/mdl_sync.test:
Adjusted test case after replacing custom global read lock
implementation with one based on metadata locks. Replaced
usage of GRL-specific debug_sync's with appropriate sync
points in MDL subsystem. Updated thread state names which
are used when DDL waits for FTWRL.
mysql-test/t/trigger_notembedded.test:
Adjusted test case after changing thread state names which
are used when DML or DDL waits for FLUSH TABLES WITH READ
LOCK to "Waiting for global read lock".
sql/event_data_objects.cc:
Removed Event_queue_element::status/last_executed_changed
members and Event_queue_element::update_timing_fields()
method. We no longer use this class for updating mysql.events
once event is chosen for execution. Accesses to instances of
this class in scheduler thread require protection by
Event_queue::LOCK_event_queue mutex and we try to avoid
updating table while holding this lock.
sql/event_data_objects.h:
Removed Event_queue_element::status/last_executed_changed
members and Event_queue_element::update_timing_fields()
method. We no longer use this class for updating mysql.events
once event is chosen for execution. Accesses to instances of
this class in scheduler thread require protection by
Event_queue::LOCK_event_queue mutex and we try to avoid
updating table while holding this lock.
sql/event_db_repository.cc:
- Changed Event_db_repository methods to not release all
metadata locks once they are done updating mysql.events
table. This allows to keep metadata lock protecting
against GRL and lock protecting particular event around
until corresponding DDL statement is written to the binary
log.
- Removed logic for conditional update of "status" and
"last_executed" fields from update_timing_fields_for_event()
method. In the only case when this method is called now
"last_executed" is always modified and tracking change
of "status" is too much hassle.
sql/event_db_repository.h:
Removed logic for conditional update of "status" and
"last_executed" fields from Event_db_repository::
update_timing_fields_for_event() method.
In the only case when this method is called now "last_executed"
is always modified and tracking change of "status" field is
too much hassle.
sql/event_queue.cc:
Changed event scheduler code not to update mysql.events
table while holding Event_queue::LOCK_event_queue mutex.
Doing so led to a deadlock with a new GRL implementation.
This deadlock didn't occur with old implementation due to
fact that code acquiring protection against GRL ignored
pending GRL requests (which lead to GRL starvation).
One of goals of new implementation is to disallow GRL
starvation and so we have to solve problem with this
deadlock in a different way.
sql/events.cc:
Changed methods of Events class to acquire protection
against GRL while perfoming DDL statement and keep it
until statement is written to the binary log.
Unfortunately this step together with new GRL implementation
exposed deadlock involving Events::LOCK_event_metadata
and GRL. To solve it Events::LOCK_event_metadata mutex was
replaced with a metadata lock on event. As a side-effect
events DDL has to be prohibited under LOCK TABLES even in
cases when mysql.events table was explicitly locked for
write.
sql/events.h:
Replaced Events::LOCK_event_metadata mutex with a metadata
lock on event.
sql/ha_ndbcluster.cc:
Updated code after replacing custom global read lock
implementation with one based on MDL. Since MDL subsystem
should now be able to detect deadlocks involving metadata
locks and GRL there is no need for special handling of
active GRL.
sql/handler.cc:
Replaced custom implementation of global read lock with
one based on metadata locks. Consequently when doing
commit instead of calling method of Global_read_lock
class to acquire protection against GRL we simply acquire
IX in COMMIT namespace.
sql/lock.cc:
Replaced custom implementation of global read lock with
one based on metadata locks. This step allows to expose
wait for GRL to deadlock detector of MDL subsystem and
thus succesfully resolve deadlocks similar to one behind
bug #57006 "Deadlock between HANDLER and FLUSH TABLES
WITH READ LOCK". It also solves problem with GRL starvation
described in bug #54673 "It takes too long to get readlock
for 'FLUSH TABLES WITH READ LOCK'" since metadata locks used
by GRL give preference to FTWRL statement instead of DML
statements (if needed in future this can be changed to
fair scheduling).
Similar to old implementation of acquisition of GRL is
two-step. During the first step we block all concurrent
DML and DDL statements by acquiring global S metadata lock
(each DML and DDL statement acquires global IX lock for
its duration). During the second step we block commits by
acquiring global S lock in COMMIT namespace (commit code
acquires global IX lock in this namespace).
Note that unlike in old implementation acquisition of
protection against GRL in DML and DDL is semi-automatic.
We assume that any statement which should be blocked by GRL
will either open and acquires write-lock on tables or acquires
metadata locks on objects it is going to modify. For any such
statement global IX metadata lock is automatically acquired
for its duration.
To support this change:
- Global_read_lock::lock/unlock_global_read_lock and
make_global_read_lock_block_commit methods were changed
accordingly.
- Global_read_lock::wait_if_global_read_lock() and
start_waiting_global_read_lock() methods were dropped.
It is now responsibility of code acquiring metadata locks
opening tables to acquire protection against GRL by
explicitly taking global IX lock with statement duration.
- Global variables, mutex and condition variable used by
old implementation was removed.
- lock_routine_name() was changed to use statement duration for
its global IX lock. It was also renamed to lock_object_name()
as it now also used to take metadata locks on events.
- Global_read_lock::set_explicit_lock_duration() was added which
allows not to release locks used for GRL when leaving prelocked
mode.
sql/lock.h:
- Renamed lock_routine_name() to lock_object_name() and changed
its signature to allow its usage for events.
- Removed broadcast_refresh() function. It is no longer needed
with new GRL implementation.
sql/log_event.cc:
Release metadata locks with statement duration at the end
of processing legacy event for LOAD DATA. This ensures that
replication thread processing such event properly releases
its protection against global read lock.
sql/mdl.cc:
Changed MDL subsystem to support new MDL-based implementation
of global read lock.
Added COMMIT and EVENTS namespaces for metadata locks. Changed
thread state name for GLOBAL namespace to "Waiting for global
read lock".
Optimized MDL_map::find_or_insert() method to avoid taking
m_mutex mutex when looking up MDL_lock objects for GLOBAL
or COMMIT namespaces. We keep pre-created MDL_lock objects
for these namespaces around and simply return pointers to
these global objects when needed.
Changed MDL_lock/MDL_scoped_lock to properly handle
notification of insert delayed handler threads when FTWRL
takes global S lock.
Introduced concept of lock duration. In addition to locks with
transaction duration which work in the way which is similar to
how locks worked before (i.e. they are released at the end of
transaction), locks with statement and explicit duration were
introduced.
Locks with statement duration are automatically released at the
end of statement. Locks with explicit duration require explicit
release and obsolete concept of transactional sentinel.
* Changed MDL_request and MDL_ticket classes to support notion
of duration.
* Changed MDL_context to keep locks with different duration in
different lists. Changed code handling ticket list to take
this into account.
* Changed methods responsible for releasing locks to take into
account duration of tickets. Particularly public
MDL_context::release_lock() method now only can release
tickets with explicit duration (there is still internal
method which allows to specify duration). To release locks
with statement or transaction duration one have to use
release_statement/transactional_locks() methods.
* Concept of savepoint for MDL subsystem now has to take into
account locks with statement duration. Consequently
MDL_savepoint class was introduced and methods working with
savepoints were updated accordingly.
* Added methods which allow to set duration for one or all
locks in the context.
sql/mdl.h:
Changed MDL subsystem to support new MDL-based implementation
of global read lock.
Added COMMIT and EVENTS namespaces for metadata locks.
Introduced concept of lock duration. In addition to locks with
transaction duration which work in the way which is similar to
how locks worked before (i.e. they are released at the end of
transaction), locks with statement and explicit duration were
introduced.
Locks with statement duration are automatically released at the
end of statement. Locks with explicit duration require explicit
release and obsolete concept of transactional sentinel.
* Changed MDL_request and MDL_ticket classes to support notion
of duration.
* Changed MDL_context to keep locks with different duration in
different lists. Changed code handling ticket list to take
this into account.
* Changed methods responsible for releasing locks to take into
account duration of tickets. Particularly public
MDL_context::release_lock() method now only can release
tickets with explicit duration (there is still internal
method which allows to specify duration). To release locks
with statement or transaction duration one have to use
release_statement/transactional_locks() methods.
* Concept of savepoint for MDL subsystem now has to take into
account locks with statement duration. Consequently
MDL_savepoint class was introduced and methods working with
savepoints were updated accordingly.
* Added methods which allow to set duration for one or all
locks in the context.
sql/mysqld.cc:
Removed global mutex and condition variables which were used
by old implementation of GRL.
Also we no longer need to initialize Events::LOCK_event_metadata
mutex as it was replaced with metadata locks on events.
sql/mysqld.h:
Removed global variable, mutex and condition variables which
were used by old implementation of GRL.
sql/rpl_rli.cc:
When slave thread closes tables which were open for handling
of RBR events ensure that it releases global IX lock which
was acquired as protection against GRL.
sql/sp.cc:
Adjusted code to the new signature of lock_object/routine_name(),
to the fact that one now needs specify duration of lock when
initializing MDL_request and to the fact that savepoints for MDL
subsystem are now represented by MDL_savepoint class.
sql/sp_head.cc:
Ensure that statements in stored procedures release statement
metadata locks and thus release their protectiong against GRL
in proper moment in time.
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request.
sql/sql_admin.cc:
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request.
sql/sql_base.cc:
- Implemented support for new approach to acquiring protection
against global read lock. We no longer acquire such protection
explicitly on the basis of statement flags. Instead we always
rely on code which is responsible for acquiring metadata locks
on object to be changed acquiring this protection. This is
achieved by acquiring global IX metadata lock with statement
duration. Code doing this also responsible for checking that
current connection has no active GRL by calling an
Global_read_lock::can_acquire_protection() method.
Changed code in open_table() and lock_table_names()
accordingly.
Note that as result of this change DDL and DML on temporary
tables is always compatible with GRL (before it was
incompatible in some cases and compatible in other cases).
- To speed-up code acquiring protection against GRL introduced
m_has_protection_against_grl member in Open_table_context
class. It indicates that protection was already acquired
sometime during open_tables() execution and new attempts
can be skipped.
- Thanks to new GRL implementation calls to broadcast_refresh()
became unnecessary and were removed.
- Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request and to the fact that
savepoints for MDL subsystem are now represented by
MDL_savepoint class.
sql/sql_base.h:
Adjusted code to the fact that savepoints for MDL subsystem are
now represented by MDL_savepoint class.
Also introduced Open_table_context::m_has_protection_against_grl
member which allows to avoid acquiring protection against GRL
while opening tables if such protection was already acquired.
sql/sql_class.cc:
Changed THD::leave_locked_tables_mode() after transactional
sentinel for metadata locks was obsoleted by introduction of
locks with explicit duration.
sql/sql_class.h:
- Adjusted code to the fact that savepoints for MDL subsystem
are now represented by MDL_savepoint class.
- Changed Global_read_lock class according to changes in
global read lock implementation:
* wait_if_global_read_lock and start_waiting_global_read_lock
are now gone. Instead code needing protection against GRL
has to acquire global IX metadata lock with statement
duration itself. To help it new can_acquire_protection()
was introduced. Also as result of the above change
m_protection_count member is gone too.
* Added m_mdl_blocks_commits_lock member to store metadata
lock blocking commits.
* Adjusted code to the fact that concept of transactional
sentinel was obsoleted by concept of lock duration.
- Removed CF_PROTECT_AGAINST_GRL flag as it is no longer
necessary. New GRL implementation acquires protection
against global read lock automagically when statement
acquires metadata locks on tables or other objects it
is going to change.
sql/sql_db.cc:
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request.
sql/sql_handler.cc:
Removed call to broadcast_refresh() function. It is no longer
needed with new GRL implementation.
Adjusted code after introducing duration concept for metadata
locks. Particularly to the fact transactional sentinel was
replaced with explicit duration.
sql/sql_handler.h:
Renamed mysql_ha_move_tickets_after_trans_sentinel() to
mysql_ha_set_explicit_lock_duration() after transactional
sentinel was obsoleted by locks with explicit duration.
sql/sql_insert.cc:
Adjusted code handling delaying inserts after switching to
new GRL implementation. Now connection thread initiating
delayed insert has to acquire global IX lock in addition
to metadata lock on table being inserted into. This IX lock
protects against GRL and similarly to SW lock on table being
inserted into has to be passed to handler thread in order to
avoid deadlocks.
sql/sql_lex.cc:
LEX::protect_against_global_read_lock member is no longer
necessary since protection against GRL is automatically
taken by code acquiring metadata locks/opening tables.
sql/sql_lex.h:
LEX::protect_against_global_read_lock member is no longer
necessary since protection against GRL is automatically
taken by code acquiring metadata locks/opening tables.
sql/sql_parse.cc:
- Implemented support for new approach to acquiring protection
against global read lock. We no longer acquire such protection
explicitly on the basis of statement flags. Instead we always
rely on code which is responsible for acquiring metadata locks
on object to be changed acquiring this protection. This is
achieved by acquiring global IX metadata lock with statement
duration. This lock is automatically released at the end of
statement execution.
- Changed implementation of CREATE/DROP PROCEDURE/FUNCTION not
to release metadata locks and thus protection against of GRL
in the middle of statement execution.
- Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request and to the fact that
savepoints for MDL subsystem are now represented by
MDL_savepoint class.
sql/sql_prepare.cc:
Adjusted code to the to the fact that savepoints for MDL
subsystem are now represented by MDL_savepoint class.
sql/sql_rename.cc:
With new GRL implementation there is no need to explicitly
acquire protection against GRL before renaming tables.
This happens automatically in code which acquires metadata
locks on tables being renamed.
sql/sql_show.cc:
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request and to the fact that
savepoints for MDL subsystem are now represented by
MDL_savepoint class.
sql/sql_table.cc:
- With new GRL implementation there is no need to explicitly
acquire protection against GRL before dropping tables.
This happens automatically in code which acquires metadata
locks on tables being dropped.
- Changed mysql_alter_table() not to release lock on new table
name explicitly and to rely on automatic release of locks
at the end of statement instead. This was necessary since
now MDL_context::release_lock() is supported only for locks
for explicit duration.
sql/sql_trigger.cc:
With new GRL implementation there is no need to explicitly
acquire protection against GRL before changing table triggers.
This happens automatically in code which acquires metadata
locks on tables which triggers are to be changed.
sql/sql_update.cc:
Fix bug exposed by GRL testing. During prepare phase acquire
only S metadata locks instead of SW locks to keep prepare of
multi-UPDATE compatible with concurrent LOCK TABLES WRITE
and global read lock.
sql/sql_view.cc:
With new GRL implementation there is no need to explicitly
acquire protection against GRL before creating view.
This happens automatically in code which acquires metadata
lock on view to be created.
sql/sql_yacc.yy:
LEX::protect_against_global_read_lock member is no longer
necessary since protection against GRL is automatically
taken by code acquiring metadata locks/opening tables.
sql/table.cc:
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request.
sql/table.h:
Adjusted code to the fact that one now needs specify duration
of lock when initializing MDL_request.
sql/transaction.cc:
Replaced custom implementation of global read lock with
one based on metadata locks. Consequently when doing
commit instead of calling method of Global_read_lock
class to acquire protection against GRL we simply acquire
IX in COMMIT namespace.
Also adjusted code to the fact that MDL savepoint is now
represented by MDL_savepoint class.
MDL deadlock detector".
Deadlock could have occurred when workload containing mix
of DML, DDL and FLUSH TABLES statements affecting same
set of tables was executed in heavily concurrent environment.
This deadlock occurred when several connections tried to
perform deadlock detection in metadata locking subsystem.
The first connection started traversing wait-for graph,
encountered sub-graph representing wait for flush, acquired
LOCK_open and dived into sub-graph inspection. When it has
encounterd sub-graph corresponding to wait for metadata lock
and blocked while trying to acquire rd-lock on
MDL_lock::m_rwlock (*) protecting this subgraph, since some
other thread had wr-lock on it. When this wr-lock was released
it could have happened (if there was other pending wr-lock
against this rwlock) that rd-lock from the first connection
was left unsatisfied but at the same time new rd-lock request
from the second connection sneaked in and was satisfied (for
this to be possible second rd- request should come exactly
after wr-lock is released but before pending wr-lock manages
to grab rwlock, which is possible both on Linux and in our
own rwlock implementation). If this second connection
continued traversing wait-for graph and encountered sub-graph
representing wait for flush it tried to acquire LOCK_open
and thus deadlock was created.
This patch tries to workaround this problem but not allowing
deadlock detector to lock LOCK_open mutex if some other thread
doing deadlock detection already owns it and current search
depth is greater than 0. Instead deadlock is reported.
Other possible solutions are either known to have negative
effects on performance or require much more time for proper
implementation and testing.
No test case is provided as this bug is very hard to repeat
in MTR environment but is repeatable with the help of RQG
tests.
sql/mdl.cc:
Moved Deadlock_detection_visitor::m_current_search_depth to
parent class to make it available in
TABLE_SHARE::visit_subgraph().
Added MDL_wait_for_graph_visitor::abort_traversal() method
which allows to abort traversal of a wait-for graph and
report a deadlock.
sql/mdl.h:
Moved Deadlock_detection_visitor::m_current_search_depth to
parent class to make it available in
TABLE_SHARE::visit_subgraph().
Added MDL_wait_for_graph_visitor::abort_traversal() method
which allows to abort traversal of a wait-for graph and
report a deadlock.
sql/sql_base.cc:
Added dd_owns_lock_open counter and mutex protecting it to
track number of connections which do deadlock detection and
own or try to acquire LOCK_open.
sql/sql_base.h:
Added dd_owns_lock_open counter and mutex protecting it to
track number of connections which do deadlock detection and
own or try to acquire LOCK_open.
sql/table.cc:
Workaround bug #56405 but not allowing MDL deadlock detector
to lock LOCK_open mutex if some other thread doing deadlock
detection already owns it and current search depth is greater
than 0. Instead report deadlock.
Remove acquisition of LOCK_open around file system operations,
since such operations are now protected by metadata locks.
Rework table discovery algorithm to not require LOCK_open.
No new tests added since all MDL locking operations are covered
in lock.test and mdl_sync.test, and as long as these tests
pass despite the increased concurrency, consistency must be
unaffected.
mysql-test/t/disabled.def:
Disable NDB tests due to Bug#55799.
sql/datadict.cc:
No longer necessary to protect ha_create_table() with
LOCK_open. Serial execution is now ensured by metadata
locks.
sql/ha_ndbcluster.cc:
Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.cc:
Do not manipulate with LOCK_open in cluster code.
sql/ha_ndbcluster_binlog.h:
Update function signature.
sql/handler.cc:
Implement ha_check_if_table_exists().
@todo: some engines provide ha_table_exists_in_engine()
handlerton call, for those we perhaps shouldn't
call ha_discover(), to be more efficient.
Since currently it's only NDB, postpone till
integration with NDB.
sql/handler.h:
Declare ha_check_if_table_exists() function.
sql/mdl.cc:
Remove an obsolete comment.
sql/sql_base.cc:
Update to a new signature of close_cached_tables():
from now on we always call it without LOCK_open.
Update comments.
Remove get_table_share_with_create(), we should
not attempt to create a table under LOCK_open.
Introduce get_table_share_with_discover() instead,
which would request a back off action if the table
exists in engine.
Remove acquisition of LOCK_open for
data dictionary operations, such as check_if_table_exists().
Do not use get_table_share_with_create/discover for views,
where it's not needed.
Make tdc_remove_table() optionally acquire LOCK_open
to simplify usage of this function.
Use the right mutex in the partitioning code when
manipulating with thd->open_tables.
sql/sql_base.h:
Update signatures of changes functions.
sql/sql_insert.cc:
Do not wrap quick_rm_table() with LOCK_open acquisition,
this is unnecessary.
sql/sql_parse.cc:
Update to the new calling convention of tdc_remove_table().
Update to the new signature of close_cached_tables().
Update comments.
sql/sql_rename.cc:
Update to the new calling convention of tdc_remove_table().
Remove acquisition of LOCK_open around filesystem
operations.
sql/sql_show.cc:
Remove get_trigger_table_impl().
Do not acquire LOCK_open for a dirty read of the trigger
file.
sql/sql_table.cc:
Do not acquire LOCK_open for filesystem operations.
sql/sql_trigger.cc:
Do not require LOCK_open for trigger file I/O.
sql/sql_truncate.cc:
Update to the new signature of tdc_remove_table().
sql/sql_view.cc:
Do not require LOCK_open for view I/O.
Use tdc_remove_table() to expel view share.
Update comments.
sql/sys_vars.cc:
Update to the new signature of close_cached_tables().
