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* Merge bb-10.2-ext into 10.3Marko Mäkelä2018-01-151-4/+1
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| * Compilation speed (#546)Eugene Kosov2018-01-141-4/+1
| | | | | | | | | | | | Speed up compilation Standard C++ headers contribute a lot to compilation time. Avoid algorithm and sstream in frequently used headers.
* | Added DBUG_ASSERT_AS_PRINTF compile flagMonty2017-08-241-1/+1
|/ | | | | | | | | | | | | | | | | | If compiling a non DBUG binary with -DDBUG_ASSERT_AS_PRINTF asserts will be changed to printf + stack trace (of stack trace are enabled). - Changed #ifndef DBUG_OFF to #ifdef DBUG_ASSERT_EXISTS for those DBUG_OFF that was just used to enable assert - Assert checking that could greatly impact performance where changed to DBUG_ASSERT_SLOW which is not affected by DBUG_ASSERT_AS_PRINTF - Added one extra option to my_print_stacktrace() to get more silent in case of stack trace printing as part of assert.
* MDEV-11227 - mysqlimport -l doesn't issue UNLOCK TABLESSergey Vojtovich2016-12-211-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implementation of MDEV-7660 introduced unwanted incompatible change: modifications under LOCK TABLES with autocommit enabled are rolled back on disconnect. Previously everything was committed, because LOCK TABLES didn't adjust autocommit setting. This patch restores original behavior by reverting some changes done in MDEV-7660: - sql/sql_parse.cc: do not reset autocommit on LOCK TABLES - sql/sql_base.cc: do not set autocommit on UNLOCK TABLES - test cases: main.lock_tables_lost_commit, main.partition_explicit_prune, rpl.rpl_switch_stm_row_mixed, tokudb.nested_txn_implicit_commit, tokudb_bugs.db806 But it makes InnoDB tables under LOCK TABLES ... READ [LOCAL] not protected against DML. To restore protection some changes from WL#6671 were merged, specifically MDL_SHARED_READ_ONLY and test cases. WL#6671 merge highlights: - Not all tests merged. - In MySQL LOCK TABLES ... READ acquires MDL_SHARED_READ_ONLY for all engines, in MariaDB MDL_SHARED_READ is always acquired first and then upgraded to MDL_SHARED_READ_ONLY for InnoDB only. - The above allows us to omit MDL_SHARED_WRITE_LOW_PRIO implementation in MariaDB, which is rather useless with InnoDB. In MySQL it is needed to preserve locking behavior between low priority writes and LOCK TABLES ... READ for non-InnoDB engines (covered by sys_vars.sql_low_priority_updates_func). - Omitted HA_NO_READ_LOCAL_LOCK, we rely on lock_count() instead. - Omitted "piglets": in MariaDB stream of DML against InnoDB table may lead to concurrent LOCK TABLES ... READ starvation. - HANDLER ... OPEN acquires MDL_SHARED_READ instead of MDL_SHARED in MariaDB. - Omitted SNRW->X MDL lock upgrade for IMPORT/DISCARD TABLESPAECE under LOCK TABLES. - Omitted strong locks for views, triggers and SP under LOCK TABLES. - Omitted IX schema lock for LOCK TABLES READ. - Omitted deadlock weight juggling for LOCK TABLES. Full WL#6671 merge status: - innodb.innodb-lock: fully merged - main.alter_table: not merged due to different HANDLER solution - main.debug_sync: fully merged - main.handler_innodb: not merged due to different HANDLER solution - main.handler_myisam: not merged due to different HANDLER solution - main.innodb_mysql_lock: fully merged - main.insert_notembedded: fully merged - main.lock: not merged (due to no strong locks for views) - main.lock_multi: not merged - main.lock_sync: fully merged (partially in MDEV-7660) - main.mdl_sync: not merged - main.partition_debug_sync: not merged due to different HANDLER solution - main.status: fully merged - main.view: fully merged - perfschema.mdl_func: not merged (no such test in MariaDB) - perfschema.table_aggregate_global_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_global_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_global_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_global_4u_3t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_global_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_global_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_global_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_global_4u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_hist_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_hist_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_hist_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_hist_4u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_thread_2u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_thread_2u_3t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_thread_4u_2t: not merged (didn't fail in MariaDB) - perfschema.table_lock_aggregate_thread_4u_3t: not merged (didn't fail in MariaDB) - sys_vars.sql_low_priority_updates_func: not merged - include/thr_rwlock.h: not merged, rw_pr_lock_assert_write_owner and rw_pr_lock_assert_not_write_owner are macros in MariaDB - sql/handler.h: not merged (HA_NO_READ_LOCAL_LOCK) - sql/mdl.cc: partially merged (MDL_SHARED_READ_ONLY only) - sql/mdl.h: partially merged (MDL_SHARED_READ_ONLY only) - sql/lock.cc: fully merged - sql/sp_head.cc: not merged - sql/sp_head.h: not merged - sql/sql_base.cc: partially merged (MDL_SHARED_READ_ONLY only) - sql/sql_base.h: not merged - sql/sql_class.cc: fully merged - sql/sql_class.h: fully merged - sql/sql_handler.cc: merged partially (different solution in MariaDB) - sql/sql_parse.cc: partially merged, mostly omitted low priority write part - sql/sql_reload.cc: not merged comment change - sql/sql_table.cc: not merged SNRW->X upgrade for IMPORT/DISCARD TABLESPACE - sql/sql_view.cc: not merged - sql/sql_yacc.yy: not merged (MDL_SHARED_WRITE_LOW_PRIO, MDL_SHARED_READ_ONLY) - sql/table.cc: not merged (MDL_SHARED_WRITE_LOW_PRIO) - sql/table.h: not merged (MDL_SHARED_WRITE_LOW_PRIO) - sql/trigger.cc: not merged - storage/innobase/handler/ha_innodb.cc: merged store_lock()/lock_count() changes (in MDEV-7660), didn't merge HA_NO_READ_LOCAL_LOCK - storage/innobase/handler/ha_innodb.h: fully merged in MDEV-7660 - storage/myisammrg/ha_myisammrg.cc: not merged comment change - storage/perfschema/table_helper.cc: not merged (no MDL support in MariaDB PFS) - unittest/gunit/mdl-t.cc: not merged - unittest/gunit/mdl_sync-t.cc: not merged MariaDB specific changes: - handler.heap: different HANDLER solution, MDEV-7660 - handler.innodb: different HANDLER solution, MDEV-7660 - handler.interface: different HANDLER solution, MDEV-7660 - handler.myisam: different HANDLER solution, MDEV-7660 - main.mdl_sync: MDEV-7660 specific changes - main.partition_debug_sync: removed test due to different HANDLER solution, MDEV-7660 - main.truncate_coverage: removed test due to different HANDLER solution, MDEV-7660 - mysql-test/include/mtr_warnings.sql: additional cleanup, MDEV-7660 - mysql-test/lib/v1/mtr_report.pl: additional cleanup, MDEV-7660 - plugin/metadata_lock_info/metadata_lock_info.cc: not in MySQL - sql/sql_handler.cc: MariaDB specific fix for mysql_ha_read(), MDEV-7660
* MDEV-8791 - AIX: Unresolved Symbols during linkingSergey Vojtovich2016-10-311-9/+0
| | | | | | | | | | | | | | | | | | | | | | | | | Clean-up nolock.h: it doesn't serve any purpose anymore. Appropriate code moved to x86-gcc.h and my_atomic.h. If gcc sync bultins were detected, we want to make use of them independently of __GNUC__ definition. E.g. XLC simulates those, but doesn't define __GNUC__. HS/Spider: According to AIX manual alloca() returns char*, which cannot be casted to any type with static_cast. Use explicit cast instead. MDL: Removed namemangling pragma, which didn't let MariaDB build with XLC. WSREP: _int64 seem to be conflicting name with XLC, replaced with _integer64. CONNECT: RTLD_NOLOAD is GNU extention. Removed rather meaningless check if library is loaded. Multiple dlopen()'s of the same library are permitted, and it never gets closed anyway. Except for error, which was a bug: it may close library, which can still be referenced by other subsystems. InnoDB: __ppc_get_timebase() is GNU extention. Only use it when __GLIBC__ is defined. Based on contribution by flynn1973.
* Merge branch 'github/10.0-galera' into 10.1Sergei Golubchik2015-11-191-0/+2
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| * refs codership/mysql-wsrep#202 Added schema info into wsrep messagesPhilip Stoev2015-10-191-0/+1
| | | | | | | | Added schema info to wsrep messages above debug level.
| * Refs codership/mysql-wsrep#113 - Extended the protection of local FLUSHsjaakola2015-09-091-1/+2
| | | | | | | | sessions to cover all exclusive MDL locks
| * maria-10.0.16 mergeNirbhay Choubey2015-01-261-1/+1
| |\ | | | | | | | | | | | | bzr merge -r4588 maria/10.0
| * \ bzr merge -r4209 maria/10.0.Nirbhay Choubey2014-05-211-0/+2
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| * \ \ Merging mariadb-10.0.10.Nirbhay Choubey2014-04-081-15/+1
| |\ \ \ | | | | | | | | | | | | | | | | | | | | * bzr merge -rtag:mariadb-10.0.10 maria/10.0.
| * \ \ \ * bzr merge -rtag:mariadb-10.0.9 maria/10.0Nirbhay Choubey2014-03-261-0/+15
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | * Fix for post-merge build failures.
| * \ \ \ \ Merge MariaDB-10.0.7 revision 3961.Jan Lindström2014-01-251-0/+6
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| * \ \ \ \ \ merge with MariaDB 5.6 bzr merge lp:maria --rtag:mariadb-10.0.6Seppo Jaakola2013-12-041-3/+1
| |\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | and a number of fixes to make this buildable. Run also few short multi-master high conflict rate tests, with no issues
| * | | | | | | bzr merge -r3904..3928 lp:codership-mysql/5.5Seppo Jaakola2013-11-271-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is now otherwise on level wsrep-25.9, but storage/innobase has not been fully merged wsrep-5.5 is not good source for that, so we probably have to cherry pick innodb changes from wsrep-5.6
| * | | | | | | Merged revisions 3425..3430 from mariadb-galera-5.5Seppo Jaakola2013-10-071-0/+3
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| * | | | | | | Merge 10.0 to galera-10.0Jan Lindström2013-09-031-17/+108
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| * | | | | | | Initial merge result with mariaDB 10: lp:mariaSeppo Jaakola2013-07-131-0/+3
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* | | | | | | | - Renaming variables so that they don't shadow others (After this patch one ↵Monty2015-07-061-6/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | can compile with -Wshadow and get much fewer warnings) - 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.
* | | | | | | | MDEV-6089 - MySQL WL#7305 "Improve MDL scalability by using lock-free hash"Sergey Vojtovich2015-03-041-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Replaced hash with lock-free hash.
* | | | | | | | MDEV-6089 - MySQL WL#7305 "Improve MDL scalability by using lock-free hash"Sergey Vojtovich2015-03-041-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Removed MDL map partitions. Won't be needed when this MDEV is implemented.
* | | | | | | | MDEV-6089 - MySQL WL#7305 "Improve MDL scalability by using lock-free hash"Sergey Vojtovich2015-03-041-7/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Removed MDL objects cache. Won't be needed when this MDEV is implemented.
* | | | | | | | Merge branch '10.0' into merge-wipSergei Golubchik2015-01-311-1/+1
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| * | | | | | | MDEV-7186 get_lock() crashes on Windows, main.sp_notembedded and ↵Sergei Golubchik2015-01-191-1/+1
| | |_|_|_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | main.trigger_notembedded fail in buildbot user locks are not affected by lowed_case_table_names
* | | | | | | cleanup: s/const CHARSET_INFO/CHARSET_INFO/Sergei Golubchik2014-12-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | as CHARSET_INFO is already const, using const on it is redundant and results in compiler warnings (on Windows)
* | | | | | | MDEV-4018 : Feature Request: microseconds in GET_LOCK()Nirbhay Choubey2014-11-301-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Updated MDL_context's lock methods to accept double precision lock_wait_timeout.
* | | | | | | cleanup: galera merge, simple changesSergei Golubchik2014-10-011-2/+0
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* | | | | | | MDEV-6247: Merge 10.0-galera to 10.1.Jan Lindström2014-08-261-1/+11
|/ / / / / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* | | | | | Asserting correct database name lettercase inSergei Golubchik2014-05-011-0/+2
| |_|_|_|/ |/| | | | | | | | | | | | | | various places in the code.
* | | | | MDEV-5864 - Reduce usage of LOCK_open: TABLE_SHARE::tdc.free_tablesSergey Vojtovich2014-03-201-15/+1
| |_|_|/ |/| | | | | | | | | | | | | | | | | | | 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.
* | | | MDEV-5675 - Performance: my_hash_sort_bin is called too oftenSergey Vojtovich2014-03-061-0/+15
| |_|/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* | | MDEV-4748 - metadata_lock_info pluginSergey Vojtovich2013-12-161-2/+5
| | | | | | | | | | | | | | | - restore find_ticket() private status, declare friend function instead - added metadata_lock_info to DEFAULT_SUITES
* | | add metadata_lock_infoKentoku SHIBA2013-12-111-2/+5
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* | 10.0-monty mergeSergei Golubchik2013-07-211-17/+103
|\ \ | |/ |/| | | | | | | | | | | 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
| * More merge fixes:Michael Widenius2013-06-161-13/+91
| | | | | | | | | | | | | | | | | | | | | | - mdl.cc and mdl.h merged completely - mysql_system_tables*.sql merged completely - Fixed wrong merge of lock_tables - Added some missing functions: - bool THD::notify_shared_lock() - Dynamic_array::pop, Dynamic_array::del - Added MDL_context_owner to THD - Added metadata_locks_hash_instances
| * Applied all changes from Igor and SanjaMichael Widenius2013-06-151-4/+15
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| * Temporary commit of 10.0-mergeMichael Widenius2013-03-261-1/+1
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* | 10.0-base mergeSergei Golubchik2013-04-151-16/+36
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| * MDEV-3917 multiple use locks (GET_LOCK) in one connection.Alexey Botchkov2013-04-121-14/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
| * merge with mysql-5.5.30 minus few incorrect or not applicable changesetsSergei Golubchik2013-02-281-2/+8
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| | * Bug #15954872 "MAKE MDL SUBSYSTEM AND TABLE DEFINITION CACHEDmitry Lenev2012-12-111-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ROBUST AGAINST BUGS IN CALLERS". Both MDL subsystems and Table Definition Cache code assume that callers ensure that names of objects passed to them are not longer than NAME_LEN bytes. Unfortunately due to bugs in callers this assumption might be broken in some cases. As result we get nasty bugs causing buffer overruns when we construct MDL key or TDC key from object names. This patch makes MDL and TDC code more robust against such bugs by ensuring that we always checking size of result buffer when constructing MDL and TDC keys. This doesn't free its callers from ensuring that both db and table names are shorter than NAME_LEN bytes. But at least these steps prevents buffer overruns in case of bug in caller, replacing them with less harmful behavior. This is 5.5-only version of patch. Changed code of MDL_key::mdl_key_init() to take into account size of buffer for the key. Introduced new version of create_table_def_key() helper function which constructs TDC key without risk of result buffer overrun. Places in code that construct TDC keys were changed to use this function. Also changed rm_temporary_table() and open_new_frm() functions to avoid use of "unsafe" strmov() and strxmov() functions and use safer strnxmov() instead.
| | * Bug #15948123: SERVER WORKS INCORRECT WITH LONG TABLE ALIASESGleb Shchepa2012-12-051-2/+0
| | | | | | | | | | | | | | | Post-push cleanup: removal of unneeded assertions.
| | * Bug #15948123: SERVER WORKS INCORRECT WITH LONG TABLE ALIASESGleb Shchepa2012-12-051-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code in MDL subsystem assumes that identifiers of objects can't be longer than NAME_LEN characters. This assumption was broken when one tried to construct MDL_key based on table alias, which can have arbitrary length. Since MDL_key's (and MDL locks) are not really used for table aliases this patch changes code to not initialize MDL_key object for table list element representing aliases.
* | | merge with 5.5Sergei Golubchik2012-11-031-0/+6
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| * | mysql-5.5.28Sergei Golubchik2012-10-161-0/+6
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| | * Bug#13058122 - DML, LOCK/UNLOCK TABLES AND SELECT LEAD TO Praveenkumar Hulakund2012-08-071-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* | | fixes for test failuresSergei Golubchik2012-09-271-13/+29
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* | mysql-5.5 mergeSergei Golubchik2012-01-161-0/+8
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| * Fix for bug#12695572 - "IMPROVE MDL PERFORMANCE IN PRE-VISTADmitry Lenev2011-11-151-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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.
* | mysql-5.5.18 mergeSergei Golubchik2011-11-031-7/+20
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