mariadb

Commit Graph

Author	SHA1	Message	Date
Dmitry Shulga	5ca6880def	Fixed bug#54486 - assert in my_seek, concurrent DROP/CREATE SCHEMA, CREATE TABLE, REPAIR. The cause of assert was concurrent execution of DROP DATABASE and REPAIR TABLE where first statement deleted table's file .TMD at the same time as REPAIR TABLE tried to read file details from the old file that was just removed. Additionally was fixed trouble when DROP TABLE try delete all files belong to table being dropped at the same time when REPAIR TABLE statement has just deleted .TMD file. No regression test added because this would require adding a sync point to mysys/my_redel.c. Since this bug is not present in 5.5+, adding test coverage was considered unnecessary. The patch has been verified using RQG testing. sql/sql_db.cc: mysql_rm_known_files() modified: ignore possible ENOENT error when trying delete all table's files. Such aggressive algorithm permits skip already deleted (in another thread) files. Installation of Drop_table_error_handler as internal error handler moved from mysql_rm_db() to mysql_rm_knowns_files() near to place where source of possible errors (call to mysql_rm_table_part2) located. storage/myisam/mi_check.c: mi_repair() was modified: set param->retry_repair= 0 in order to don't call following failover procedure in ha_myisam::repair().	15 years ago
Dmitry Shulga	dfb622726a	Fixed bug#54486 - assert in my_seek, concurrent DROP/CREATE SCHEMA, CREATE TABLE, REPAIR. The cause of assert was concurrent execution of DROP DATABASE and REPAIR TABLE where first statement deleted table's file .TMD at the same time as REPAIR TABLE tried to read file details from the old file that was just removed. Additionally was fixed trouble when DROP TABLE try delete all files belong to table being dropped at the same time when REPAIR TABLE statement has just deleted .TMD file. No regression test added because this would require adding a sync point to mysys/my_redel.c. Since this bug is not present in 5.5+, adding test coverage was considered unnecessary. The patch has been verified using RQG testing.	15 years ago
Jon Olav Hauglid	1e9f239e8f	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR The problem was that DROP DATABASE ignored any metadata locks on stored functions and procedures held by other connections. This made it possible for DROP DATABASE to drop functions/procedures that were in use by other connections and therefore break statement based replication. (DROP DATABASE could appear in the binlog before a statement using a dropped function/procedure.) This problem was an issue left unresolved by the patch for Bug#30977 where metadata locks for stored functions/procedures were introduced. This patch fixes the problem by making sure DROP DATABASE takes exclusive metadata locks on all stored functions/procedures to be dropped. Test case added to sp-lock.test.	15 years ago
Jon Olav Hauglid	ed928b14be	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR The problem was that DROP DATABASE ignored any metadata locks on stored functions and procedures held by other connections. This made it possible for DROP DATABASE to drop functions/procedures that were in use by other connections and therefore break statement based replication. (DROP DATABASE could appear in the binlog before a statement using a dropped function/procedure.) This problem was an issue left unresolved by the patch for Bug#30977 where metadata locks for stored functions/procedures were introduced. This patch fixes the problem by making sure DROP DATABASE takes exclusive metadata locks on all stored functions/procedures to be dropped. Test case added to sp-lock.test.	15 years ago
Jon Olav Hauglid	0ef8d8e26c	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR This pre-requisite patch refactors the code for dropping tables, used by DROP TABLE and DROP DATABASE. The patch moves the code for acquiring metadata locks out of mysql_rm_table_part2() and makes it the responsibility of the caller. This in preparation of changing the DROP DATABASE implementation to acquire all metadata locks before any changes are made. mysql_rm_table_part2() is renamed mysql_rm_table_no_locks() to reflect the change.	15 years ago
Jon Olav Hauglid	a84d750300	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR This pre-requisite patch refactors the code for dropping tables, used by DROP TABLE and DROP DATABASE. The patch moves the code for acquiring metadata locks out of mysql_rm_table_part2() and makes it the responsibility of the caller. This in preparation of changing the DROP DATABASE implementation to acquire all metadata locks before any changes are made. mysql_rm_table_part2() is renamed mysql_rm_table_no_locks() to reflect the change.	15 years ago
Jon Olav Hauglid	a3d9a26d3b	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR This pre-requisite patch removes obsolete and dead code used to remove raid subdirectories and files during DROP DATABASE. Other parts of the raid code have already been removed in WL#5498 and the support for MyISAM raid tables was removed in 5.0.	15 years ago
Jon Olav Hauglid	294f3865cd	Bug #57663 Concurrent statement using stored function and DROP DATABASE breaks SBR This pre-requisite patch removes obsolete and dead code used to remove raid subdirectories and files during DROP DATABASE. Other parts of the raid code have already been removed in WL#5498 and the support for MyISAM raid tables was removed in 5.0.	15 years ago
Konstantin Osipov	78fa2e4d6d	Implement a fix for Bug#57058 -- send SERVER_QUERY_WAS_SLOW over network when a query was slow. When a query is slow, sent a special flag to the client indicating this fact. Add a test case. Implement review comments. include/mysql_com.h: Clear SERVER_QUERY_WAS_SLOW at end of each statement. Since this patch removes the technique when thd->server_status is modified briefly only to execute my_eof(), reset more server status bit that may remain in the status from execution of the previous statement. sql/protocol.cc: Always use thd->server_status to in net_* functions to send the latest status to the client. sql/sp_head.cc: Calculate if a query was slow before sending EOF packet. sql/sql_cursor.cc: Remove juggling with thd->server_status. The extra status bits are reset at start of the next statement. sql/sql_db.cc: Remove juggling with thd->server_status. The extra status bits are reset at start of the next statement. sql/sql_error.cc: Remove m_server_status member, it's not really part of the Diagnostics_area. sql/sql_error.h: Remove server_status member, it's not part of the Diagnostics_area. The associated hack is removed as well. sql/sql_parse.cc: Do not calculate if a query was slow twice. Use a status flag in thd->server_status. tests/mysql_client_test.c: Add a test case for Bug#57058. Check that the status is present at the client, when sent.	15 years ago
Konstantin Osipov	4749b88494	Implement a fix for Bug#57058 -- send SERVER_QUERY_WAS_SLOW over network when a query was slow. When a query is slow, sent a special flag to the client indicating this fact. Add a test case. Implement review comments.	15 years ago
Dmitry Lenev	6bf6272fda	Patch that refactors global read lock implementation and fixes 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.	15 years ago
Dmitry Lenev	378cdc58c1	Patch that refactors global read lock implementation and fixes 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.	15 years ago
Magne Mahre	95d91c0f57	Bug #46941 crash with lower_case_table_names=2 and foreign key data dictionary confusion On file systems with case insensitive file names, and lower_case_table_names set to '2', the server could crash due to a table definition cache inconsistency. This is the default setting on MacOSX, but may also be set and used on MS Windows. The bug is caused by using two different strategies for creating the hash key for the table definition cache, resulting in failure to look up an entry which is present in the cache, or failure to delete an existing entry. One strategy was to use the real table name (with case preserved), and the other to use a normalized table name (i.e a lower case version). This is manifested in two cases. One is during 'DROP DATABASE', where all known files are removed. The removal from the table definition cache is done via a generated list of TABLE_LIST with keys (wrongly) created using the case preserved name. The other is during CREATE TABLE, where the cache lookup is also (wrongly) based on the case preserved name. The fix was to use only the normalized table name when creating hash keys. sql/sql_db.cc: Normalize table name (i.e lower case it) sql/sql_table.cc: table_name contains the normalized name alias contains the real table name	15 years ago
Magne Mahre	1c68d2efe7	Bug #46941 crash with lower_case_table_names=2 and foreign key data dictionary confusion On file systems with case insensitive file names, and lower_case_table_names set to '2', the server could crash due to a table definition cache inconsistency. This is the default setting on MacOSX, but may also be set and used on MS Windows. The bug is caused by using two different strategies for creating the hash key for the table definition cache, resulting in failure to look up an entry which is present in the cache, or failure to delete an existing entry. One strategy was to use the real table name (with case preserved), and the other to use a normalized table name (i.e a lower case version). This is manifested in two cases. One is during 'DROP DATABASE', where all known files are removed. The removal from the table definition cache is done via a generated list of TABLE_LIST with keys (wrongly) created using the case preserved name. The other is during CREATE TABLE, where the cache lookup is also (wrongly) based on the case preserved name. The fix was to use only the normalized table name when creating hash keys.	15 years ago
Davi Arnaut	f56dd32bf7	Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled Essentially, the problem is that safemalloc is excruciatingly slow as it checks all allocated blocks for overrun at each memory management primitive, yielding a almost exponential slowdown for the memory management functions (malloc, realloc, free). The overrun check basically consists of verifying some bytes of a block for certain magic keys, which catches some simple forms of overrun. Another minor problem is violation of aliasing rules and that its own internal list of blocks is prone to corruption. Another issue with safemalloc is rather the maintenance cost as the tool has a significant impact on the server code. Given the magnitude of memory debuggers available nowadays, especially those that are provided with the platform malloc implementation, maintenance of a in-house and largely obsolete memory debugger becomes a burden that is not worth the effort due to its slowness and lack of support for detecting more common forms of heap corruption. Since there are third-party tools that can provide the same functionality at a lower or comparable performance cost, the solution is to simply remove safemalloc. Third-party tools can provide the same functionality at a lower or comparable performance cost. The removal of safemalloc also allows a simplification of the malloc wrappers, removing quite a bit of kludge: redefinition of my_malloc, my_free and the removal of the unused second argument of my_free. Since free() always check whether the supplied pointer is null, redudant checks are also removed. Also, this patch adds unit testing for my_malloc and moves my_realloc implementation into the same file as the other memory allocation primitives. client/mysqldump.c: Pass my_free directly as its signature is compatible with the callback type -- which wasn't the case for free_table_ent.	16 years ago
Davi Arnaut	a10ae35328	Bug#34043: Server loops excessively in _checkchunk() when safemalloc is enabled Essentially, the problem is that safemalloc is excruciatingly slow as it checks all allocated blocks for overrun at each memory management primitive, yielding a almost exponential slowdown for the memory management functions (malloc, realloc, free). The overrun check basically consists of verifying some bytes of a block for certain magic keys, which catches some simple forms of overrun. Another minor problem is violation of aliasing rules and that its own internal list of blocks is prone to corruption. Another issue with safemalloc is rather the maintenance cost as the tool has a significant impact on the server code. Given the magnitude of memory debuggers available nowadays, especially those that are provided with the platform malloc implementation, maintenance of a in-house and largely obsolete memory debugger becomes a burden that is not worth the effort due to its slowness and lack of support for detecting more common forms of heap corruption. Since there are third-party tools that can provide the same functionality at a lower or comparable performance cost, the solution is to simply remove safemalloc. Third-party tools can provide the same functionality at a lower or comparable performance cost. The removal of safemalloc also allows a simplification of the malloc wrappers, removing quite a bit of kludge: redefinition of my_malloc, my_free and the removal of the unused second argument of my_free. Since free() always check whether the supplied pointer is null, redudant checks are also removed. Also, this patch adds unit testing for my_malloc and moves my_realloc implementation into the same file as the other memory allocation primitives.	16 years ago
Dmitry Lenev	10582e2abe	A follow-up for 5.5 version of fix for bug#54360 "Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER". Remove wait_for_condition() which became unused after database locks were replaced with MDL scoped locks. If one needs functionality provided by this call one can always use THD::enter_cond()/exit_cond() methods. Also removed an unused include from sql_db.cc and updated comment describing one of used includes to reflect current situation.	16 years ago
Dmitry Lenev	8ad1aa562f	A follow-up for 5.5 version of fix for bug#54360 "Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER". Remove wait_for_condition() which became unused after database locks were replaced with MDL scoped locks. If one needs functionality provided by this call one can always use THD::enter_cond()/exit_cond() methods. Also removed an unused include from sql_db.cc and updated comment describing one of used includes to reflect current situation.	16 years ago
Jon Olav Hauglid	9ff272fbbd	A 5.5 version of the fix for Bug #54360 "Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER" Remove LOCK_create_db, database name locks, and use metadata locks instead. This exposes CREATE/DROP/ALTER DATABASE statements to the graph-based deadlock detector in MDL, and paves the way for a safe, deadlock-free implementation of RENAME DATABASE. Database DDL statements will now take exclusive metadata locks on the database name, while table/view/routine DDL statements take intention exclusive locks on the database name. This prevents race conditions between database DDL and table/view/routine DDL. (e.g. DROP DATABASE with concurrent CREATE/ALTER/DROP TABLE) By adding database name locks, this patch implements WL#4450 "DDL locking: CREATE/DROP DATABASE must use database locks" and WL#4985 "DDL locking: namespace/hierarchical locks". The patch also changes code to use init_one_table() where appropriate. The new lock_table_names() function requires TABLE_LIST::db_length to be set correctly, and this is taken care of by init_one_table(). This patch also adds a simple template to help work with the mysys HASH data structure. Most of the patch was written by Konstantin Osipov.	16 years ago
Jon Olav Hauglid	41a3dfe490	A 5.5 version of the fix for Bug #54360 "Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER" Remove LOCK_create_db, database name locks, and use metadata locks instead. This exposes CREATE/DROP/ALTER DATABASE statements to the graph-based deadlock detector in MDL, and paves the way for a safe, deadlock-free implementation of RENAME DATABASE. Database DDL statements will now take exclusive metadata locks on the database name, while table/view/routine DDL statements take intention exclusive locks on the database name. This prevents race conditions between database DDL and table/view/routine DDL. (e.g. DROP DATABASE with concurrent CREATE/ALTER/DROP TABLE) By adding database name locks, this patch implements WL#4450 "DDL locking: CREATE/DROP DATABASE must use database locks" and WL#4985 "DDL locking: namespace/hierarchical locks". The patch also changes code to use init_one_table() where appropriate. The new lock_table_names() function requires TABLE_LIST::db_length to be set correctly, and this is taken care of by init_one_table(). This patch also adds a simple template to help work with the mysys HASH data structure. Most of the patch was written by Konstantin Osipov.	16 years ago
Jon Olav Hauglid	b4593605e0	Bug #54360 Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER This deadlock happened if DROP DATABASE was blocked due to an open HANDLER table from a different connection. While DROP DATABASE is blocked, it holds the LOCK_mysql_create_db mutex. This results in a deadlock if the connection with the open HANDLER table tries to execute a CREATE/ALTER/DROP DATABASE statement as they all try to acquire LOCK_mysql_create_db. This patch makes this deadlock scenario very unlikely by closing and marking for re-open all HANDLER tables for which there are pending conflicing locks, before LOCK_mysql_create_db is acquired. However, there is still a very slight possibility that a connection could access one of these HANDLER tables between closing/marking for re-open and the acquisition of LOCK_mysql_create_db. This patch is for 5.1 only, a separate and complete fix will be made for 5.5+. Test case added to schema.test.	16 years ago
Jon Olav Hauglid	9fa66b6440	Bug #54360 Deadlock DROP/ALTER/CREATE DATABASE with open HANDLER This deadlock happened if DROP DATABASE was blocked due to an open HANDLER table from a different connection. While DROP DATABASE is blocked, it holds the LOCK_mysql_create_db mutex. This results in a deadlock if the connection with the open HANDLER table tries to execute a CREATE/ALTER/DROP DATABASE statement as they all try to acquire LOCK_mysql_create_db. This patch makes this deadlock scenario very unlikely by closing and marking for re-open all HANDLER tables for which there are pending conflicing locks, before LOCK_mysql_create_db is acquired. However, there is still a very slight possibility that a connection could access one of these HANDLER tables between closing/marking for re-open and the acquisition of LOCK_mysql_create_db. This patch is for 5.1 only, a separate and complete fix will be made for 5.5+. Test case added to schema.test.	16 years ago
Jon Olav Hauglid	a1c6a39a13	Backport from mysql-6.0-codebase of: ------------------------------------------------------------ revno: 3672 committer: lars-erik.bjork@sun.com branch nick: 48067-mysql-6.0-codebase-bugfixing timestamp: Mon 2009-10-26 13:51:43 +0100 message: This is a patch for bug#48067 "A temp table with the same name as an existing table, makes drop database fail" When dropping the database, mysql_rm_known_files() reads the contents of the database directory, and creates a TABLE_LIST object, for each .frm file encountered. Temporary tables, however, are not associated with any .frm file. The list of tables to drop are passed to mysql_rm_table_part2(). This method prefers temporary tables over regular tables, so if there is a temporary table with the same name as a regular, the temporary is removed, leaving the regular table intact. Regular tables are only deleted if there are no temporary tables with the same name. This fix ensures, that for all TABLE_LIST objects that are created by mysql_rm_known_files(), 'open_type' is set to 'OT_BASE_ONLY', to indicate that this is a regular table. In all cases in mysql_rm_table_part2() where we prefer a temporary table to a non-temporary table, we chek if 'open_type' equals 'OT_BASE_ONLY'. mysql-test/r/temp_table.result: The expected result of the test. mysql-test/t/temp_table.test: Test based on the bug report. sql/sql_db.cc: For all TABLE_LIST objects that are created by mysql_rm_known_files(), 'open_type' is set to 'OT_BASE_ONLY', to indicate that these are regular tables. sql/sql_table.cc: Check if 'open_type' is set to 'OT_BASE_ONLY, every place a temporary table is preferred to a non-temporary table.	16 years ago
Jon Olav Hauglid	be3005d9e7	Backport from mysql-6.0-codebase of: ------------------------------------------------------------ revno: 3672 committer: lars-erik.bjork@sun.com branch nick: 48067-mysql-6.0-codebase-bugfixing timestamp: Mon 2009-10-26 13:51:43 +0100 message: This is a patch for bug#48067 "A temp table with the same name as an existing table, makes drop database fail" When dropping the database, mysql_rm_known_files() reads the contents of the database directory, and creates a TABLE_LIST object, for each .frm file encountered. Temporary tables, however, are not associated with any .frm file. The list of tables to drop are passed to mysql_rm_table_part2(). This method prefers temporary tables over regular tables, so if there is a temporary table with the same name as a regular, the temporary is removed, leaving the regular table intact. Regular tables are only deleted if there are no temporary tables with the same name. This fix ensures, that for all TABLE_LIST objects that are created by mysql_rm_known_files(), 'open_type' is set to 'OT_BASE_ONLY', to indicate that this is a regular table. In all cases in mysql_rm_table_part2() where we prefer a temporary table to a non-temporary table, we chek if 'open_type' equals 'OT_BASE_ONLY'.	16 years ago
Michael Widenius	5a2f40d48a	Fixes for Opensolaris (to get buildbot green) - Fixed memory leaks in mysqldump - Fixed printf of NULL which caused crashes on OpenSolaris when using --debug - Fixed realloc() problem that caused out of memory when running mysqldump.test on OpenSolaris client/mysqldump.c: Fixed memory leaks Fixed printf of NULL which caused crashes on OpenSolaris when using --debug client/mysqltest.cc: Fixed printf of NULL which caused crashes on OpenSolaris when using --debug include/my_global.h: Added simple macro val_or_null() to simplify detecting of NULL strings for printf sql/handler.cc: Fixed printf of NULL which caused crashes on OpenSolaris when using --debug sql/sql_db.cc: Fixed printf of NULL which caused crashes on OpenSolaris when using --debug Removed testing of 'new_db_name' as this is guranteed never NULL sql/sql_show.cc: Fixed printf of NULL which caused crashes on OpenSolaris when using --debug storage/csv/ha_tina.cc: Fixed realloc() problem that caused out of memory when running mysqldump.test on OpenSolaris (OpenSolaris default malloc() can't handle a lot of reallocs() of strings that are growing one byte at a time) This did speed up logging to cvs with a magnitude for large strings.	16 years ago
Dmitry Lenev	bee0f214fd	Pre-requisite patch for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". The goal of this patch is to decouple type of metadata lock acquired for table by open_tables() from type of table-level lock to be acquired on it. To achieve this we change approach to how we determine what type of metadata lock should be acquired on table to be open. Now instead of inferring it at open_tables() time from flags and type of table-level lock we rely on that type of metadata lock is properly set at parsing time and is not changed further. sql/ha_ndbcluster.cc: Now one needs to properly initialize table list element's MDL_request object before calling mysql_rm_table_part2(). sql/lock.cc: lock_table_names() no longer initializes table list elements' MDL_request objects. Now proper initialization of these requests is a responsibility of the caller. sql/lock.h: Removed MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag which became unnecessary. Thanks to the fact that we don't reset type of requests for metadata locks between re-executions we now can figure out that upgradable locks are requested by simply looking at their type which were set in the parser. As result this flag became redundant. sql/mdl.h: Added version of new operator which simplifies allocation of MDL_request objects on a MEM_ROOT. sql/sp_head.cc: Added comment explaining why it is OK to infer type of metadata lock to request from type of table-level lock for prelocking. Added enum_mdl_type argument to sp_add_to_query_tables() to simplify its usage in trigger implementation. sql/sp_head.h: Added enum_mdl_type argument to sp_add_to_query_tables() to simplify its usage in trigger implementation. sql/sql_base.cc: - open_table_get_mdl_lock(): Preserve type of MDL_request for table list element which was set in the parser by creating MDL_request objects on memory root if MYSQL_OPEN_FORCE_SHARED_MDL or MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag were specified. Thanks to this and to the fact that we no longer reset type of requests for metadata locks between re-executions we no longer need to acquire exclusive metadata lock on table to be created in a special way. This lock is acquired by code handling acquiring of upgradable locks. Also changed signature/calling convention for this function to simplify its usage. - Accordingly special lock strategy for table list elements which was used for such locks became unnecessary and was removed. Other strategies were renamed. - Since we no longer have guarantee that MDL_request object which were not satisfied due to lock conflict belongs to table list element Open_table_context class and its methods were extended to remember pointer to MDL_request which has caused problem at request_backoff_action() time and use it in recover_from_failed_open(). Similar approach is used for cases when problem from which we need to recover is not related to MDL but to the table itself. In this case we store pointer to the element of table list. - Changed open_tables()/open_tables_check_upgradable_mdl()/ open_tables_acquire_upgradable_mdl() not to rely on MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to understand when upgradable metadata locks should be acquired and not to infer type of MDL lock from type of table-level lock. Instead we assume that type of MDL to be acquired was set in the parser (we can do this as type of MDL_request is no longer reset between re-executions). sql/sql_class.h: Since we no longer have guarantee that MDL_request object which were not satisfied due to lock conflict belongs to table list element Open_table_context class and its methods were extended to remember pointer to MDL_request which has caused problem at request_backoff_action() time and use it in recover_from_failed_open(). Similar approach is used for cases when problem from which we need to recover is not related to MDL but to the table itself. In this case we store pointer to the element of table list. sql/sql_db.cc: Now one needs to properly initialize table list element's MDL_request object before calling mysql_rm_table_part2() or mysql_rename_tables(). sql/sql_lex.cc: st_select_lex/st_select_lex_node::add_table_to_list() method now has argument which allows specify type of metadata lock to be requested for table list element being added. sql/sql_lex.h: - st_select_lex/st_select_lex_node::add_table_to_list() method now has argument which specifies type of metadata lock to be requested for table list element being added. This allows to explicitly set type of MDL lock to be acquired for a DDL statement in parser. It is also more future-proof than inferring type of MDL request from type of table-level lock. - Added Yacc_state::m_mdl_type member which specifies which type of metadata lock should be requested for tables to be added to table list by a grammar rule in cases when the same rule is used in several statements requiring different kinds of metadata locks. sql/sql_parse.cc: - st_select_lex::add_table_to_list() method now has argument which specifies type of metadata lock to be requested for table list element being added. This allows to explicitly set type of MDL lock to be acquired for a DDL statement in parser. It is also more future-proof than inferring type of MDL request from type of table-level lock. - EXCLUSIVE_DOWNGRADABLE_MDL lock strategy has a new name - OTLS_DOWNGRADE_IF_EXISTS. - Adjusted LOCK TABLES implementation to the fact that we no longer infer type of metadata lock to be acquired from table level lock and that type of MDL request is set at parsing. And thus MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag became unnecessary. sql/sql_prepare.cc: TABLE_LIST's lock strategy SHARED_MDL was renamed to OTLS_NONE as now it means that metadata lock should not be changed during call to open_table() (if it has been already acquired) and is also used for exclusive metadata lock. sql/sql_show.cc: st_select_lex::add_table_to_list() method now has argument which specifies type of metadata lock to be requested for table list element being added. sql/sql_table.cc: - Adjusted mysql_admin_table()'s code to the fact that open_tables() no longer determines what kind of metadata lock should be obtained basing on type of table-level lock and flags. Instead type of metadata lock for table to be open should be set before calling open_tables(). - Changed mysql_alter_table() code to the facts: a) that now it is responsibility of caller to properly initalize MDL_request in table list elements before calling lock_table_names() b) and that MYSQL_OPEN_TAKE_UPGRADABLE_MDL is no longer necessary since type of metadata lock to be obtained at open_tables() time is set during parsing. - Changed code of mysql_recreate_table() to properly set type of metadata and table-level lock to be obtained by mysql_alter_table() which it calls. sql/sql_trigger.cc: Instead of relying on MYSQL_OPEN_TAKE_UPGRADABLE_MDL flag to force open_tables() to take an upgradable lock we now specify exact type of lock to be taken when constructing table list element for table to be open for CREATE/DROP TRIGGER. sql/sql_view.cc: We no longer use TABLE_LIST::EXCLUSIVE_MDL strategy to force open_tables() to take an exclusive metadata lock on view to be created. Instead we rely on parser setting proper type of metadata lock to request and open_tables() acquiring it. This became possible thanks to the fact that we no longer reset type of MDL_request between statement re-executions. sql/sql_yacc.yy: Instead of inferring type of MDL_request for table to be open from type of table-level lock and flags passed to open_tables() we now explicitly specify them at parsing. This became possible thanks to the fact that we no longer reset type of MDL_request between statement re-executions. In future this should allow to decouple type of metadata lock from type of table-level lock. The only exception to this approach is statements implemented through mysql_admin_table() which re-uses same table list element several times with different types of table-level and metadata locks. We now also properly initialize MDL_request objects for table list elements which are later passed to lock_table_names() function. sql/table.cc: Do not reset type of MDL_request between statement re-executions. This became unnecessesary as we no longer change type of MDL_request residing in table list element. In its turn this change allows to set type of MDL_request only once - at parsing time. sql/table.h: Got rid of TABLE_LIST::EXCLUSIVE_MDL lock strategy. Now we can specify that we need to acquire exclusive lock on table to be processed by open_tables() through setting an appropriate type of MDL_request at parsing time (this became possible thanks to the fact that we no longer reset types of MDL_request's belonging to table list elements between statement re-execution). Strategy SHARED_MDL was renamed to OTLS_NONE as now it means that metadata lock should not be changed during call to open_table() (if it has been already acquired) and is also used for exclusive metadata lock. Strategy EXCLUSIVE_DOWNGRADABLE_MDL was renamed to OTLS_DOWNGRADE_IF_EXISTS.	16 years ago
Dmitry Lenev	a3c080be7a	Pre-requisite patch for bug #51263 "Deadlock between transactional SELECT and ALTER TABLE ... REBUILD PARTITION". The goal of this patch is to decouple type of metadata lock acquired for table by open_tables() from type of table-level lock to be acquired on it. To achieve this we change approach to how we determine what type of metadata lock should be acquired on table to be open. Now instead of inferring it at open_tables() time from flags and type of table-level lock we rely on that type of metadata lock is properly set at parsing time and is not changed further.	16 years ago
Mats Kindahl	46bd78b9ee	WL#5030: Splitting mysql_priv.h Adding my_global.h first in all files using NO_EMBEDDED_ACCESS_CHECKS. Correcting a merge problem resulting from a changed definition of check_some_access compared to the original patches.	16 years ago
Mats Kindahl	0768deeb27	WL#5030: Splitting mysql_priv.h Adding my_global.h first in all files using NO_EMBEDDED_ACCESS_CHECKS. Correcting a merge problem resulting from a changed definition of check_some_access compared to the original patches.	16 years ago
Mats Kindahl	23d8586dbf	WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h	16 years ago
Mats Kindahl	e409d6f69c	WL#5030: Split and remove mysql_priv.h This patch: - Moves all definitions from the mysql_priv.h file into header files for the component where the variable is defined - Creates header files if the component lacks one - Eliminates all include directives from mysql_priv.h - Eliminates all circular include cycles - Rename time.cc to sql_time.cc - Rename mysql_priv.h to sql_priv.h	16 years ago
Konstantin Osipov	7116431a8a	A review comment for the fix for Bug#46672. Remove unnecessary need_reopen loops.	16 years ago
Konstantin Osipov	9cb8a98216	A review comment for the fix for Bug#46672. Remove unnecessary need_reopen loops.	16 years ago
Konstantin Osipov	00dc9a6e70	Merge next-mr -> next-4284. Cherry-pick a fix Bug#37148 from next-mr, to preserve file ids of the added files, and ensure that all the necessary changes have been pulled. Since initially Bug#37148 was null-merged into 6.0, the changeset that is now being cherry-picked was likewise null merged into next-4284. Now that Bug#37148 has been reapplied to 6.0, try to make it work with next-4284. This is also necessary to be able to pull other changes from 5.1-rep into next-4284. To resolve the merge issues use this changeset applied to 6.0: revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9 revno: 3776.1.1 committer: He Zhenxing <zhenxing.he@sun.com> branch nick: 6.0-codebase-bugfixing timestamp: Thu 2009-12-17 17:02:50 +0800 message: Fix merge problem with Bug#37148	16 years ago
Konstantin Osipov	06e1a73af6	Merge next-mr -> next-4284. Cherry-pick a fix Bug#37148 from next-mr, to preserve file ids of the added files, and ensure that all the necessary changes have been pulled. Since initially Bug#37148 was null-merged into 6.0, the changeset that is now being cherry-picked was likewise null merged into next-4284. Now that Bug#37148 has been reapplied to 6.0, try to make it work with next-4284. This is also necessary to be able to pull other changes from 5.1-rep into next-4284. To resolve the merge issues use this changeset applied to 6.0: revid:jperkin@sun.com-20091216103628-ylhqf7s6yegui2t9 revno: 3776.1.1 committer: He Zhenxing <zhenxing.he@sun.com> branch nick: 6.0-codebase-bugfixing timestamp: Thu 2009-12-17 17:02:50 +0800 message: Fix merge problem with Bug#37148	16 years ago
Dmitry Lenev	eba5d30e67	Implement new type-of-operation-aware metadata locks. Add a wait-for graph based deadlock detector to the MDL subsystem. Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and bug #37346 "innodb does not detect deadlock between update and alter table". The first bug manifested itself as an unwarranted abort of a transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER statement, when this transaction tried to repeat use of a table, which it has already used in a similar fashion before ALTER started. The second bug showed up as a deadlock between table-level locks and InnoDB row locks, which was "detected" only after innodb_lock_wait_timeout timeout. A transaction would start using the table and modify a few rows. Then ALTER TABLE would come in, and start copying rows into a temporary table. Eventually it would stumble on the modified records and get blocked on a row lock. The first transaction would try to do more updates, and get blocked on thr_lock.c lock. This situation of circular wait would only get resolved by a timeout. Both these bugs stemmed from inadequate solutions to the problem of deadlocks occurring between different locking subsystems. In the first case we tried to avoid deadlocks between metadata locking and table-level locking subsystems, when upgrading shared metadata lock to exclusive one. Transactions holding the shared lock on the table and waiting for some table-level lock used to be aborted too aggressively. We also allowed ALTER TABLE to start in presence of transactions that modify the subject table. ALTER TABLE acquires TL_WRITE_ALLOW_READ lock at start, and that block all writes against the table (naturally, we don't want any writes to be lost when switching the old and the new table). TL_WRITE_ALLOW_READ lock, in turn, would block the started transaction on thr_lock.c lock, should they do more updates. This, again, lead to the need to abort such transactions. The second bug occurred simply because we didn't have any mechanism to detect deadlocks between the table-level locks in thr_lock.c and row-level locks in InnoDB, other than innodb_lock_wait_timeout. This patch solves both these problems by moving lock conflicts which are causing these deadlocks into the metadata locking subsystem, thus making it possible to avoid or detect such deadlocks inside MDL. To do this we introduce new type-of-operation-aware metadata locks, which allow MDL subsystem to know not only the fact that transaction has used or is going to use some object but also what kind of operation it has carried out or going to carry out on the object. This, along with the addition of a special kind of upgradable metadata lock, allows ALTER TABLE to wait until all transactions which has updated the table to go away. This solves the second issue. Another special type of upgradable metadata lock is acquired by LOCK TABLE WRITE. This second lock type allows to solve the first issue, since abortion of table-level locks in event of DDL under LOCK TABLES becomes also unnecessary. Below follows the list of incompatible changes introduced by this patch: - From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those statements that acquire TL_WRITE_ALLOW_READ lock) wait for all transactions which has updated the table to complete. - From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE (i.e. all statements which acquire TL_WRITE table-level lock) wait for all transaction which updated or read from the table to complete. As a consequence, innodb_table_locks=0 option no longer applies to LOCK TABLES ... WRITE. - DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort statements or transactions which use tables being dropped or renamed, and instead wait for these transactions to complete. - Since LOCK TABLES WRITE now takes a special metadata lock, not compatible with with reads or writes against the subject table and transaction-wide, thr_lock.c deadlock avoidance algorithm that used to ensure absence of deadlocks between LOCK TABLES WRITE and other statements is no longer sufficient, even for MyISAM. The wait-for graph based deadlock detector of MDL subsystem may sometimes be necessary and is involved. This may lead to ER_LOCK_DEADLOCK error produced for multi-statement transactions even if these only use MyISAM: session 1: session 2: begin; update t1 ... lock table t2 write, t1 write; -- gets a lock on t2, blocks on t1 update t2 ... (ER_LOCK_DEADLOCK) - Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE was abandoned. LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same priority as the usual LOCK TABLE ... WRITE. SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in the wait queue. - We do not take upgradable metadata locks on implicitly locked tables. So if one has, say, a view v1 that uses table t1, and issues: LOCK TABLE v1 WRITE; FLUSH TABLE t1; -- (or just 'FLUSH TABLES'), an error is produced. In order to be able to perform DDL on a table under LOCK TABLES, the table must be locked explicitly in the LOCK TABLES list. mysql-test/include/handler.inc: Adjusted test case to trigger an execution path on which bug 41110 "crash with handler command when used concurrently with alter table" and bug 41112 "crash in mysql_ha_close_table/get_lock_data with alter table" were originally discovered. Left old test case which no longer triggers this execution path for the sake of coverage. Added test coverage for HANDLER SQL statements and type-aware metadata locks. Added a test for the global shared lock and HANDLER SQL. Updated tests to take into account that the old simple deadlock detection heuristics was replaced with a graph-based deadlock detector. mysql-test/r/debug_sync.result: Updated results (see debug_sync.test). mysql-test/r/handler_innodb.result: Updated results (see handler.inc test). mysql-test/r/handler_myisam.result: Updated results (see handler.inc test). mysql-test/r/innodb-lock.result: Updated results (see innodb-lock.test). mysql-test/r/innodb_mysql_lock.result: Updated results (see innodb_mysql_lock.test). mysql-test/r/lock.result: Updated results (see lock.test). mysql-test/r/lock_multi.result: Updated results (see lock_multi.test). mysql-test/r/lock_sync.result: Updated results (see lock_sync.test). mysql-test/r/mdl_sync.result: Updated results (see mdl_sync.test). mysql-test/r/sp-threads.result: SHOW PROCESSLIST output has changed due to the fact that waiting for LOCK TABLES WRITE now happens within metadata locking subsystem. mysql-test/r/truncate_coverage.result: Updated results (see truncate_coverage.test). mysql-test/suite/funcs_1/datadict/processlist_val.inc: SELECT FROM I_S.PROCESSLIST output has changed due to fact that waiting for LOCK TABLES WRITE now happens within metadata locking subsystem. mysql-test/suite/funcs_1/r/processlist_val_no_prot.result: SELECT FROM I_S.PROCESSLIST output has changed due to fact that waiting for LOCK TABLES WRITE now happens within metadata locking subsystem. mysql-test/suite/rpl/t/rpl_sp.test: Updated to a new SHOW PROCESSLIST state name. mysql-test/t/debug_sync.test: Use LOCK TABLES READ instead of LOCK TABLES WRITE as the latter no longer allows to trigger execution path involving waiting on thr_lock.c lock and therefore reaching debug sync-point covered by this test. mysql-test/t/innodb-lock.test: Adjusted test case to the fact that innodb_table_locks=0 option is no longer supported, since LOCK TABLES WRITE handles all its conflicts within MDL subsystem. mysql-test/t/innodb_mysql_lock.test: Added test for bug #37346 "innodb does not detect deadlock between update and alter table". mysql-test/t/lock.test: Added test coverage which checks the fact that we no longer support DDL under LOCK TABLES on tables which were locked implicitly. Adjusted existing test cases accordingly. mysql-test/t/lock_multi.test: Added test for bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock". Adjusted other test cases to take into account the fact that waiting for LOCK TABLES ... WRITE now happens within MDL subsystem. mysql-test/t/lock_sync.test: Since LOCK TABLES ... WRITE now takes SNRW metadata lock for tables locked explicitly we have to implicitly lock InnoDB tables (through view) to trigger the table-level lock conflict between TL_WRITE and TL_WRITE_ALLOW_WRITE. mysql-test/t/mdl_sync.test: Added basic test coverage for type-of-operation-aware metadata locks. Also covered with tests some use cases involving HANDLER statements in which a deadlock could arise. Adjusted existing tests to take type-of-operation-aware MDL into account. mysql-test/t/multi_update.test: Update to a new SHOW PROCESSLIST state name. mysql-test/t/truncate_coverage.test: Adjusted test case after making LOCK TABLES WRITE to wait until transactions that use the table to be locked are completed. Updated to the changed name of DEBUG_SYNC point. sql/handler.cc: Global read lock functionality has been moved into a class. sql/lock.cc: Global read lock functionality has been moved into a class. Updated code to use the new MDL API. sql/mdl.cc: Introduced new type-of-operation aware metadata locks. To do this: - Changed MDL_lock to use one list for waiting requests and one list for granted requests. For each list, added a bitmap that holds information what lock types a list contains. Added a helper class MDL_lock::List to manipulate with granted and waited lists while keeping the bitmaps in sync with list contents. - Changed lock-compatibility functions to use bitmaps that define compatibility. - Introduced a graph based deadlock detector inspired by waiting_threads.c from Maria implementation. - Now that we have a deadlock detector, and no longer have a global lock to protect individual lock objects, but rather use an rw lock per object, removed redundant code for upgrade, and the global read lock. Changed the MDL API to no longer require the caller to acquire the global intention exclusive lock by means of a separate method. Removed a few more methods that became redundant. - Removed deadlock detection heuristic, it has been made obsolete by the deadlock detector. - With operation-type-aware metadata locks, MDL subsystem has become aware of potential conflicts between DDL and open transactions. This made it possible to remove calls to mysql_abort_transactions_with_shared_lock() from acquisition paths for exclusive lock and lock upgrade. Now we can simply wait for these transactions to complete without fear of deadlock. Function mysql_lock_abort() has also become unnecessary for all conflicting cases except when a DDL conflicts with a connection that has an open HANDLER. sql/mdl.h: Introduced new type-of-operation aware metadata locks. Introduced a graph based deadlock detector and supporting methods. Added comments. God rid of redundant API calls. Renamed m_lt_or_ha_sentinel to m_trans_sentinel, since now it guards the global read lock as well as LOCK TABLES and HANDLER locks. sql/mysql_priv.h: Moved the global read lock functionality into a class. Added MYSQL_OPEN_FORCE_SHARED_MDL flag which forces open_tables() to take MDL_SHARED on tables instead of metadata locks specified in the parser. We use this to allow PREPARE run concurrently in presence of LOCK TABLES ... WRITE. Added signature for find_table_for_mdl_ugprade(). sql/set_var.cc: Global read lock functionality has been moved into a class. sql/sp_head.cc: When creating TABLE_LIST elements for prelocking or system tables set the type of request for metadata lock according to the operation that will be performed on the table. sql/sql_base.cc: - Updated code to use the new MDL API. - In order to avoid locks starvation we take upgradable locks all at once. As result implicitly locked tables no longer get an upgradable lock. Consequently DDL and FLUSH TABLES for such tables is prohibited. find_write_locked_table() was replaced by find_table_for_mdl_upgrade() function. open_table() was adjusted to return TABLE instance with upgradable ticket when necessary. - We no longer wait for all locks on OT_WAIT back off action -- only on the lock that caused the wait conflict. Moreover, now we distinguish cases when we have to wait due to conflict in MDL and old version of table in TDC. - Upate mysql_notify_threads_having_share_locks() to only abort thr_lock.c waits of threads that have open HANDLERs, since lock conflicts with only these threads now can lead to deadlocks not detectable by the MDL deadlock detector. - Remove mysql_abort_transactions_with_shared_locks() which is no longer needed. sql/sql_class.cc: Global read lock functionality has been moved into a class. Re-arranged code in THD::cleanup() to simplify assert. sql/sql_class.h: Introduced class to incapsulate global read lock functionality. Now sentinel in MDL subsystem guards the global read lock as well as LOCK TABLES and HANDLER locks. Adjusted code accordingly. sql/sql_db.cc: Global read lock functionality has been moved into a class. sql/sql_delete.cc: We no longer acquire upgradable metadata locks on tables which are locked by LOCK TABLES implicitly. As result TRUNCATE TABLE is no longer allowed for such tables. Updated code to use the new MDL API. sql/sql_handler.cc: Inform MDL_context about presence of open HANDLERs. Since HANLDERs break MDL protocol by acquiring table-level lock while holding only S metadata lock on a table MDL subsystem should take special care about such contexts (Now this is the only case when mysql_lock_abort() is used). sql/sql_parse.cc: Global read lock functionality has been moved into a class. Do not take upgradable metadata locks when opening tables for CREATE TABLE SELECT as it is not necessary and limits concurrency. When initializing TABLE_LIST objects before adding them to the table list set the type of request for metadata lock according to the operation that will be performed on the table. We no longer acquire upgradable metadata locks on tables which are locked by LOCK TABLES implicitly. As result FLUSH TABLES is no longer allowed for such tables. sql/sql_prepare.cc: Use MYSQL_OPEN_FORCE_SHARED_MDL flag when opening tables during PREPARE. This allows PREPARE to run concurrently in presence of LOCK TABLES ... WRITE. sql/sql_rename.cc: Global read lock functionality has been moved into a class. sql/sql_show.cc: Updated code to use the new MDL API. sql/sql_table.cc: Global read lock functionality has been moved into a class. We no longer acquire upgradable metadata locks on tables which are locked by LOCK TABLES implicitly. As result DROP TABLE is no longer allowed for such tables. Updated code to use the new MDL API. sql/sql_trigger.cc: Global read lock functionality has been moved into a class. We no longer acquire upgradable metadata locks on tables which are locked by LOCK TABLES implicitly. As result CREATE/DROP TRIGGER is no longer allowed for such tables. Updated code to use the new MDL API. sql/sql_view.cc: Global read lock functionality has been moved into a class. Fixed results of wrong merge that led to misuse of GLR API. CREATE VIEW statement is not a commit statement. sql/table.cc: When resetting TABLE_LIST objects for PS or SP re-execution set the type of request for metadata lock according to the operation that will be performed on the table. Do the same in auxiliary function initializing metadata lock requests in a table list. sql/table.h: When initializing TABLE_LIST objects set the type of request for metadata lock according to the operation that will be performed on the table. sql/transaction.cc: Global read lock functionality has been moved into a class.	16 years ago
Dmitry Lenev	afd15c43a9	Implement new type-of-operation-aware metadata locks. Add a wait-for graph based deadlock detector to the MDL subsystem. Fixes bug #46272 "MySQL 5.4.4, new MDL: unnecessary deadlock" and bug #37346 "innodb does not detect deadlock between update and alter table". The first bug manifested itself as an unwarranted abort of a transaction with ER_LOCK_DEADLOCK error by a concurrent ALTER statement, when this transaction tried to repeat use of a table, which it has already used in a similar fashion before ALTER started. The second bug showed up as a deadlock between table-level locks and InnoDB row locks, which was "detected" only after innodb_lock_wait_timeout timeout. A transaction would start using the table and modify a few rows. Then ALTER TABLE would come in, and start copying rows into a temporary table. Eventually it would stumble on the modified records and get blocked on a row lock. The first transaction would try to do more updates, and get blocked on thr_lock.c lock. This situation of circular wait would only get resolved by a timeout. Both these bugs stemmed from inadequate solutions to the problem of deadlocks occurring between different locking subsystems. In the first case we tried to avoid deadlocks between metadata locking and table-level locking subsystems, when upgrading shared metadata lock to exclusive one. Transactions holding the shared lock on the table and waiting for some table-level lock used to be aborted too aggressively. We also allowed ALTER TABLE to start in presence of transactions that modify the subject table. ALTER TABLE acquires TL_WRITE_ALLOW_READ lock at start, and that block all writes against the table (naturally, we don't want any writes to be lost when switching the old and the new table). TL_WRITE_ALLOW_READ lock, in turn, would block the started transaction on thr_lock.c lock, should they do more updates. This, again, lead to the need to abort such transactions. The second bug occurred simply because we didn't have any mechanism to detect deadlocks between the table-level locks in thr_lock.c and row-level locks in InnoDB, other than innodb_lock_wait_timeout. This patch solves both these problems by moving lock conflicts which are causing these deadlocks into the metadata locking subsystem, thus making it possible to avoid or detect such deadlocks inside MDL. To do this we introduce new type-of-operation-aware metadata locks, which allow MDL subsystem to know not only the fact that transaction has used or is going to use some object but also what kind of operation it has carried out or going to carry out on the object. This, along with the addition of a special kind of upgradable metadata lock, allows ALTER TABLE to wait until all transactions which has updated the table to go away. This solves the second issue. Another special type of upgradable metadata lock is acquired by LOCK TABLE WRITE. This second lock type allows to solve the first issue, since abortion of table-level locks in event of DDL under LOCK TABLES becomes also unnecessary. Below follows the list of incompatible changes introduced by this patch: - From now on, ALTER TABLE and CREATE/DROP TRIGGER SQL (i.e. those statements that acquire TL_WRITE_ALLOW_READ lock) wait for all transactions which has updated the table to complete. - From now on, LOCK TABLES ... WRITE, REPAIR/OPTIMIZE TABLE (i.e. all statements which acquire TL_WRITE table-level lock) wait for all transaction which updated or read from the table to complete. As a consequence, innodb_table_locks=0 option no longer applies to LOCK TABLES ... WRITE. - DROP DATABASE, DROP TABLE, RENAME TABLE no longer abort statements or transactions which use tables being dropped or renamed, and instead wait for these transactions to complete. - Since LOCK TABLES WRITE now takes a special metadata lock, not compatible with with reads or writes against the subject table and transaction-wide, thr_lock.c deadlock avoidance algorithm that used to ensure absence of deadlocks between LOCK TABLES WRITE and other statements is no longer sufficient, even for MyISAM. The wait-for graph based deadlock detector of MDL subsystem may sometimes be necessary and is involved. This may lead to ER_LOCK_DEADLOCK error produced for multi-statement transactions even if these only use MyISAM: session 1: session 2: begin; update t1 ... lock table t2 write, t1 write; -- gets a lock on t2, blocks on t1 update t2 ... (ER_LOCK_DEADLOCK) - Finally, support of LOW_PRIORITY option for LOCK TABLES ... WRITE was abandoned. LOCK TABLE ... LOW_PRIORITY WRITE from now on has the same priority as the usual LOCK TABLE ... WRITE. SELECT HIGH PRIORITY no longer trumps LOCK TABLE ... WRITE in the wait queue. - We do not take upgradable metadata locks on implicitly locked tables. So if one has, say, a view v1 that uses table t1, and issues: LOCK TABLE v1 WRITE; FLUSH TABLE t1; -- (or just 'FLUSH TABLES'), an error is produced. In order to be able to perform DDL on a table under LOCK TABLES, the table must be locked explicitly in the LOCK TABLES list.	16 years ago
Davi Arnaut	c3a73a8f6d	Fix for compiler warnings: Rename method as to not hide a base. Reorder attributes initialization. Remove unused variable. Rework code to silence a warning due to assignment used as truth value. sql/item_strfunc.cc: Rename method as to not hide a base. sql/item_strfunc.h: Rename method as to not hide a base. sql/log_event.cc: Reorder attributes initialization. sql/rpl_injector.cc: Rework code to silence a warning due to assignment used as truth value. sql/rpl_record.cc: Remove unused variable. sql/sql_db.cc: Rework code to silence a warning due to assignment used as truth value. sql/sql_parse.cc: Rework code to silence a warning due to assignment used as truth value. sql/sql_table.cc: Rework code to silence a warning due to assignment used as truth value.	16 years ago
Davi Arnaut	b5d307e85c	Fix for compiler warnings: Rename method as to not hide a base. Reorder attributes initialization. Remove unused variable. Rework code to silence a warning due to assignment used as truth value.	16 years ago
Mats Kindahl	e34eb3b507	Patch to eliminate warnings in mysql-next-mr-bugteam.	16 years ago
Mats Kindahl	51af6729f2	Patch to eliminate warnings in mysql-next-mr-bugteam.	16 years ago
He Zhenxing	2b16517522	Backport Bug#37148 to 5.1	16 years ago
He Zhenxing	6bf8c119fe	Backport Bug#37148 to 5.1	16 years ago
Sergey Glukhov	4a10f7b46c	Bug#49501 Inefficient information_schema check (system collation), addon removed wrongly introduced strlen calls sql/events.cc: removed wrongly introduced strlen calls sql/mysql_priv.h: removed wrongly introduced strlen calls sql/repl_failsafe.cc: removed wrongly introduced strlen calls sql/sql_db.cc: removed wrongly introduced strlen calls sql/sql_parse.cc: removed wrongly introduced strlen calls sql/sql_show.cc: removed wrongly introduced strlen calls	16 years ago
Sergey Glukhov	ed79d2ecbb	Bug#49501 Inefficient information_schema check (system collation), addon removed wrongly introduced strlen calls	16 years ago
Sergey Glukhov	81391bd00c	Bug#49501 Inefficient information_schema check (system collation) added check_length optimization for I_S_NAME comparison sql/event_data_objects.cc: added check_length optimization for I_S_NAME comparison sql/events.cc: added check_length optimization for I_S_NAME comparison sql/mysql_priv.h: added check_length optimization for I_S_NAME comparison sql/repl_failsafe.cc: added check_length optimization for I_S_NAME comparison sql/sql_db.cc: added check_length optimization for I_S_NAME comparison sql/sql_parse.cc: added check_length optimization for I_S_NAME comparison sql/sql_show.cc: added check_length optimization for I_S_NAME comparison sql/sql_view.cc: added check_length optimization for I_S_NAME comparison sql/table.cc: added check_length optimization for I_S_NAME comparison	16 years ago
Sergey Glukhov	baacdf1dae	Bug#49501 Inefficient information_schema check (system collation) added check_length optimization for I_S_NAME comparison	16 years ago
Marc Alff	c082955f06	WL#2360 Performance schema Part III: mysys instrumentation	16 years ago
Marc Alff	e33a8b2a1a	WL#2360 Performance schema Part III: mysys instrumentation	16 years ago
He Zhenxing	bc2b3d2ccc	BUG#45520 rpl_killed_ddl fails sporadically in pb2 There are three issues that caused rpl_killed_ddl fails sporadically in pb2: 1) thd->clear_error() was not called before create Query event if operation is executed successfully. 2) DATABASE d2 might do exist because the statement to CREATE or ALTER it was killed 3) because of bug 43353, kill the query that do DROP FUNCTION or DROP PROCEDURE can result in SP not found This patch fixed all above issues by: 1) Called thd->clear_error() if the operation succeeded. 2) Add IF EXISTS to the DROP DATABASE d2 statement 3) Temporarily disabled testing DROP FUNCTION/PROCEDURE IF EXISTS. mysql-test/t/rpl_killed_ddl.test: DATABASE d2 might not exists, add IF EXITS to the DROP statement sql/sql_db.cc: Called thd->clear_error() if the operation succeeded	16 years ago

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