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.
The previous fix for MDEV-3992 was incomplete, because it still computed
incorrectly the number of keyparts of the extended secondary key in the
case when columns of the PK participate in the secondary key.
This patch by Monty corrects the above problem.
Analysis:
The crash is a result of incorrect analysis of whether a secondary key
can be extended with a primary in order to compute ORDER BY. The analysis
is done in test_if_order_by_key(). This function doesn't take into account
that the primary key may in fact index the same columns as the secondary
key. For the test query test_if_order_by_key says that there is an extended
key with total 2 keyparts.
At the same time, the condition
if (pkinfo->key_part[i].field->key_start.is_set(nr))
in test_if_cheaper_oredring() becomes true for (i == 0), which results in
an invalid access to rec_per_key[-1].
Solution:
The best solution would be to reuse KEY::ext_key_parts that is already computed
by open_binary_frm(), however after detailed analysis the conclusion is that
the change would be too intrusive for a GA release.
The solution for 5.5 is to add a guard for the case when the 0-th key part is
considered, and to assume that all keys will be scanned in this case.
The bug could lead to a wrong estimate of the number of expected rows
in the output of the EXPLAIN commands for queries with GROUP BY.
This could be observed in the test case for LP bug 934348.
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.
that introduced engine independent persistent statistics.
In particular:
- added an enumeration type for possible values of the system
variable use_stat_tables
- renamed KEY::real_rec_per_key to KEY::actual_rec_per_key
- optimized the collection of statistical data for any primary
key defined only on one column.
Analysys:
In the beginning of JOIN::cleanup there is code that is supposed to
free all filesort buffers. The code assumes that the table being sorted
is the first non-constant table. To get this table it calls:
first_top_level_tab(this, WITHOUT_CONST_TABLES)
However, first_top_level_tab() instead returned the wrong table - the first
one in the plan, instead of the first non-constant table. There is no other
place outside filesort() where sort buffers may be freed. As a result, the
sort buffer was not freed, and there was a memory leak.
Solution:
Change first_top_level_tab(), to test for WITH_CONST_TABLES instead of
WITHOUT_CONST_TABLES.
The problem was that in debugging binaries it try to print item to assign human readable name to the item.
But subquery item was already freed (join_free/cleanup with full cleanup) so Item_field refers to temporary
table which memory had been already freed.
If the setting of system variables does not allow to use join buffer
for a join query with GROUP BY <f1,...> / ORDER BY <f1,...> then
filesort is not needed if the first joined table is scanned in
the order compatible with order specified by the list <f1,...>.
MDEV-567: Wrong result from a query with correlated subquery if ICP is allowed:
backport the fix developed for SHOW EXPLAIN:
revision-id: psergey@askmonty.org-20120719115219-212cxmm6qvf0wlrb
branch nick: 5.5-show-explain-r21
timestamp: Thu 2012-07-19 15:52:19 +0400
BUG#992942 & MDEV-325: Pre-liminary commit for testing
and adjust it so that it handles DS-MRR scans correctly.
If, when executing a query with ORDER BY col LIMIT n, the optimizer chose
an index-merge scan to access the table containing col while there existed
an index defined over col then optimizer did not consider the possibility
of using an alternative range scan by this index to avoid filesort. This
could cause a performance degradation if the optimizer flag index_merge was
set up to 'on'.
Problem:-
When we execute a query which has subquery with GROUP BY, ORDER BY and have a
BLOB column,results a memory leak.
Analysis:-
In case of subquery, which have GROUP BY on BLOB and a ORDER BY on other field
and BLOB is not a key. We allocate a tmp buffer to copy_field to take care of
BLOB value.This copy_field value can have copies of its in two join(objects),
so while freeing this copy_field we have to take care that it is
not deleted twice.
The double deletion of tmp_table_param.copy_field is handled by two patches.
One by Kostja :
revid:sp1r-konstantin@mysql.com-20050627101056-55153
Fix the broken test suite in -debug build.
and other by Oleksandr
revid:sp1r-bell@sanja.is.com.ua-20060118114857-19905
Excluded posibility of tmp_table_param.copy_field double deletion (BUG#14851).
both of this patches are commited in different branch and while
merging they both get placed,but there is no need for Kostja patch as Oleksandr
patch handle this.
sql/sql_select.cc:
Bug13726751, tmp_join clean up is not necessary as later in the code we are taking care of cleaning up of tmp_join copy_field.
Problem:-
When we execute a query which has subquery with GROUP BY, ORDER BY and have a
BLOB column,results a memory leak.
Analysis:-
In case of subquery, which have GROUP BY on BLOB and a ORDER BY on other field
and BLOB is not a key. We allocate a tmp buffer to copy_field to take care of
BLOB value.This copy_field value can have copies of its in two join(objects),
so while freeing this copy_field we have to take care that it is
not deleted twice.
The double deletion of tmp_table_param.copy_field is handled by two patches.
One by Kostja :
revid:sp1r-konstantin@mysql.com-20050627101056-55153
Fix the broken test suite in -debug build.
and other by Oleksandr
revid:sp1r-bell@sanja.is.com.ua-20060118114857-19905
Excluded posibility of tmp_table_param.copy_field double deletion (BUG#14851).
both of this patches are commited in different branch and while
merging they both get placed,but there is no need for Kostja patch as Oleksandr
patch handle this.
sql/sql_select.cc:
Bug13726751, tmp_join clean up is not necessary as later in the code we are taking care of cleaning up of tmp_join copy_field.
