mariadb/sql/mysqld.h

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/* Copyright 2006-2008 MySQL AB, 2008-2009 Sun Microsystems, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
#ifndef MYSQLD_INCLUDED
#define MYSQLD_INCLUDED
#include "my_global.h" /* MYSQL_PLUGIN_IMPORT, FN_REFLEN, FN_EXTLEN */
#include "sql_bitmap.h" /* Bitmap */
#include "my_decimal.h" /* my_decimal */
#include "mysql_com.h" /* SERVER_VERSION_LENGTH */
#include "my_atomic.h" /* my_atomic_rwlock_t */
#include "mysql/psi/mysql_file.h" /* MYSQL_FILE */
#include "sql_list.h" /* I_List */
class THD;
struct handlerton;
class Time_zone;
struct scheduler_functions;
typedef struct st_mysql_const_lex_string LEX_CSTRING;
typedef struct st_mysql_show_var SHOW_VAR;
/*
This forward declaration is used from C files where the real
definition is included before. Since C does not allow repeated
typedef declarations, even when identical, the definition may not be
repeated.
*/
#ifndef CHARSET_INFO_DEFINED
typedef struct charset_info_st CHARSET_INFO;
#endif /* CHARSET_INFO_DEFINED */
#if MAX_INDEXES <= 64
typedef Bitmap<64> key_map; /* Used for finding keys */
#else
typedef Bitmap<((MAX_INDEXES+7)/8*8)> key_map; /* Used for finding keys */
#endif
/* Bits from testflag */
#define TEST_PRINT_CACHED_TABLES 1
#define TEST_NO_KEY_GROUP 2
#define TEST_MIT_THREAD 4
#define TEST_BLOCKING 8
#define TEST_KEEP_TMP_TABLES 16
#define TEST_READCHECK 64 /**< Force use of readcheck */
#define TEST_NO_EXTRA 128
#define TEST_CORE_ON_SIGNAL 256 /**< Give core if signal */
#define TEST_NO_STACKTRACE 512
#define TEST_SIGINT 1024 /**< Allow sigint on threads */
#define TEST_SYNCHRONIZATION 2048 /**< get server to do sleep in
some places */
/* Function prototypes */
void kill_mysql(void);
void close_connection(THD *thd, uint errcode, bool lock);
void handle_connection_in_main_thread(THD *thd);
void create_thread_to_handle_connection(THD *thd);
void unlink_thd(THD *thd);
bool one_thread_per_connection_end(THD *thd, bool put_in_cache);
void flush_thread_cache();
void refresh_status(THD *thd);
bool is_secure_file_path(char *path);
extern MYSQL_PLUGIN_IMPORT CHARSET_INFO *system_charset_info;
extern MYSQL_PLUGIN_IMPORT CHARSET_INFO *files_charset_info ;
extern MYSQL_PLUGIN_IMPORT CHARSET_INFO *national_charset_info;
extern MYSQL_PLUGIN_IMPORT CHARSET_INFO *table_alias_charset;
/**
Character set of the buildin error messages loaded from errmsg.sys.
*/
extern CHARSET_INFO *error_message_charset_info;
extern CHARSET_INFO *character_set_filesystem;
extern MY_BITMAP temp_pool;
extern bool opt_large_files, server_id_supplied;
extern bool opt_update_log, opt_bin_log, opt_error_log;
extern my_bool opt_log, opt_slow_log;
extern my_bool opt_backup_history_log;
extern my_bool opt_backup_progress_log;
extern ulonglong log_output_options;
extern ulong log_backup_output_options;
extern my_bool opt_log_queries_not_using_indexes;
extern bool opt_disable_networking, opt_skip_show_db;
extern bool opt_skip_name_resolve;
extern bool opt_ignore_builtin_innodb;
extern my_bool opt_character_set_client_handshake;
extern bool volatile abort_loop;
extern bool in_bootstrap;
extern uint volatile thread_count, global_read_lock;
extern uint connection_count;
extern my_bool opt_safe_user_create;
extern my_bool opt_safe_show_db, opt_local_infile, opt_myisam_use_mmap;
extern my_bool opt_slave_compressed_protocol, use_temp_pool;
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extern ulong slave_exec_mode_options;
extern ulonglong slave_type_conversions_options;
extern my_bool opt_readonly, lower_case_file_system;
extern my_bool opt_enable_named_pipe, opt_sync_frm, opt_allow_suspicious_udfs;
extern my_bool opt_secure_auth;
extern char* opt_secure_file_priv;
extern char* opt_secure_backup_file_priv;
extern size_t opt_secure_backup_file_priv_len;
extern my_bool opt_log_slow_admin_statements, opt_log_slow_slave_statements;
extern my_bool sp_automatic_privileges, opt_noacl;
extern my_bool opt_old_style_user_limits, trust_function_creators;
extern uint opt_crash_binlog_innodb;
extern char *shared_memory_base_name, *mysqld_unix_port;
extern my_bool opt_enable_shared_memory;
extern char *default_tz_name;
extern Time_zone *default_tz;
extern char *default_storage_engine;
extern bool opt_endinfo, using_udf_functions;
extern my_bool locked_in_memory;
extern bool opt_using_transactions;
extern ulong current_pid;
extern ulong expire_logs_days;
extern my_bool relay_log_recovery;
extern uint sync_binlog_period, sync_relaylog_period,
sync_relayloginfo_period, sync_masterinfo_period;
extern ulong opt_tc_log_size, tc_log_max_pages_used, tc_log_page_size;
extern ulong tc_log_page_waits;
extern my_bool relay_log_purge, opt_innodb_safe_binlog, opt_innodb;
extern my_bool relay_log_recovery;
extern uint test_flags,select_errors,ha_open_options;
extern uint protocol_version, mysqld_port, dropping_tables;
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extern ulong delay_key_write_options;
extern char *opt_logname, *opt_slow_logname;
extern char *opt_backup_history_logname, *opt_backup_progress_logname,
*opt_backup_settings_name;
extern const char *log_output_str;
extern const char *log_backup_output_str;
extern char *mysql_home_ptr, *pidfile_name_ptr;
extern char glob_hostname[FN_REFLEN], mysql_home[FN_REFLEN];
extern char pidfile_name[FN_REFLEN], system_time_zone[30], *opt_init_file;
extern char default_logfile_name[FN_REFLEN];
extern char log_error_file[FN_REFLEN], *opt_tc_log_file;
extern const double log_10[309];
extern ulonglong keybuff_size;
extern ulonglong thd_startup_options;
extern ulong thread_id;
extern ulong binlog_cache_use, binlog_cache_disk_use;
extern ulong aborted_threads,aborted_connects;
extern ulong delayed_insert_timeout;
extern ulong delayed_insert_limit, delayed_queue_size;
extern ulong delayed_insert_threads, delayed_insert_writes;
extern ulong delayed_rows_in_use,delayed_insert_errors;
extern ulong slave_open_temp_tables;
extern ulong query_cache_size, query_cache_min_res_unit;
extern ulong slow_launch_threads, slow_launch_time;
extern ulong table_cache_size, table_def_size;
extern MYSQL_PLUGIN_IMPORT ulong max_connections;
extern ulong max_connect_errors, connect_timeout;
extern my_bool slave_allow_batching;
extern my_bool allow_slave_start;
extern LEX_CSTRING reason_slave_blocked;
extern ulong slave_trans_retries;
extern uint slave_net_timeout;
extern uint max_user_connections;
extern ulong what_to_log,flush_time;
extern ulong max_prepared_stmt_count, prepared_stmt_count;
extern ulong binlog_cache_size, open_files_limit;
extern ulonglong max_binlog_cache_size;
extern ulong max_binlog_size, max_relay_log_size;
extern ulong opt_binlog_rows_event_max_size;
extern ulong rpl_recovery_rank, thread_cache_size;
extern ulong back_log;
extern char language[FN_REFLEN];
extern ulong server_id, concurrency;
extern time_t server_start_time, flush_status_time;
extern char *opt_mysql_tmpdir, mysql_charsets_dir[];
extern int mysql_unpacked_real_data_home_len;
extern MYSQL_PLUGIN_IMPORT MY_TMPDIR mysql_tmpdir_list;
extern const char *first_keyword, *delayed_user, *binary_keyword;
extern MYSQL_PLUGIN_IMPORT const char *my_localhost;
extern MYSQL_PLUGIN_IMPORT const char **errmesg; /* Error messages */
extern const char *myisam_recover_options_str;
extern const char *in_left_expr_name, *in_additional_cond, *in_having_cond;
extern SHOW_VAR status_vars[];
extern struct system_variables max_system_variables;
extern struct system_status_var global_status_var;
extern struct rand_struct sql_rand;
extern const char *opt_date_time_formats[];
extern handlerton *partition_hton;
extern handlerton *myisam_hton;
extern handlerton *heap_hton;
extern const char *load_default_groups[];
extern struct my_option my_long_options[];
extern int mysqld_server_started;
extern int orig_argc;
extern char **orig_argv;
extern pthread_attr_t connection_attrib;
extern MYSQL_FILE *bootstrap_file;
extern my_bool old_mode;
extern LEX_STRING opt_init_connect, opt_init_slave;
extern int bootstrap_error;
extern I_List<THD> threads;
extern char err_shared_dir[];
extern TYPELIB thread_handling_typelib;
extern my_decimal decimal_zero;
extern pthread_key(MEM_ROOT**,THR_MALLOC);
#ifdef HAVE_PSI_INTERFACE
#ifdef HAVE_MMAP
extern PSI_mutex_key key_PAGE_lock, key_LOCK_sync, key_LOCK_active,
key_LOCK_pool;
#endif /* HAVE_MMAP */
#ifdef HAVE_OPENSSL
extern PSI_mutex_key key_LOCK_des_key_file;
#endif
extern PSI_mutex_key key_BINLOG_LOCK_index, key_BINLOG_LOCK_prep_xids,
key_delayed_insert_mutex, key_hash_filo_lock, key_LOCK_active_mi,
key_LOCK_connection_count, key_LOCK_crypt, key_LOCK_delayed_create,
key_LOCK_delayed_insert, key_LOCK_delayed_status, key_LOCK_error_log,
key_LOCK_gdl, key_LOCK_global_read_lock, key_LOCK_global_system_variables,
key_LOCK_logger, key_LOCK_manager,
key_LOCK_prepared_stmt_count,
key_LOCK_rpl_status, key_LOCK_server_started, key_LOCK_status,
key_LOCK_table_share, key_LOCK_thd_data,
key_LOCK_user_conn, key_LOCK_uuid_generator, key_LOG_LOCK_log,
key_master_info_data_lock, key_master_info_run_lock,
key_mutex_slave_reporting_capability_err_lock, key_relay_log_info_data_lock,
key_relay_log_info_log_space_lock, key_relay_log_info_run_lock,
key_structure_guard_mutex, key_TABLE_SHARE_LOCK_ha_data,
key_LOCK_error_messages, key_LOCK_thread_count, key_PARTITION_LOCK_auto_inc;
extern PSI_rwlock_key key_rwlock_LOCK_grant, key_rwlock_LOCK_logger,
key_rwlock_LOCK_sys_init_connect, key_rwlock_LOCK_sys_init_slave,
key_rwlock_LOCK_system_variables_hash, key_rwlock_query_cache_query_lock;
#ifdef HAVE_MMAP
extern PSI_cond_key key_PAGE_cond, key_COND_active, key_COND_pool;
#endif /* HAVE_MMAP */
extern PSI_cond_key key_BINLOG_COND_prep_xids, key_BINLOG_update_cond,
key_COND_cache_status_changed, key_COND_global_read_lock, key_COND_manager,
Fix for bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". The problem was that FLUSH TABLES <list> WITH READ LOCK which was issued when other connection has acquired global read lock using FLUSH TABLES WITH READ LOCK was blocked and has to wait until global read lock is released. This issue stemmed from the fact that FLUSH TABLES <list> WITH READ LOCK implementation has acquired X metadata locks on tables to be flushed. Since these locks required acquiring of global IX lock this statement was incompatible with global read lock. This patch addresses problem by using SNW metadata type of lock for tables to be flushed by FLUSH TABLES <list> WITH READ LOCK. It is OK to acquire them without global IX lock as long as we won't try to upgrade those locks. Since SNW locks allow concurrent statements using same table FLUSH TABLE <list> WITH READ LOCK now has to wait until old versions of tables to be flushed go away after acquiring metadata locks. Since such waiting can lead to deadlock MDL deadlock detector was extended to take into account waits for flush and resolve such deadlocks. As a bonus code in open_tables() which was responsible for waiting old versions of tables to go away was refactored. Now when we encounter old version of table in open_table() we don't back-off and wait for all old version to go away, but instead wait for this particular table to be flushed. Such approach supported by deadlock detection should reduce number of scenarios in which FLUSH TABLES aborts concurrent multi-statement transactions. Note that active FLUSH TABLES <list> WITH READ LOCK still blocks concurrent FLUSH TABLES WITH READ LOCK statement as the former keeps tables open and thus prevents the latter statement from doing flush. mysql-test/include/handler.inc: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/r/flush.result: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/r/mdl_sync.result: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Adjusted test results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/r/server_init.result: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/t/server_init.test: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/t/flush.test: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/t/kill.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/lock_multi.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/mdl_sync.test: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. sql/ha_ndbcluster.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/ha_ndbcluster_binlog.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/lock.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mdl.cc: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. We no longer require global IX metadata lock when acquiring SNW or SNRW locks. Such locks are needed only when metadata locks of these types are upgraded to X locks. This allows to use SNW locks in FLUSH TABLES <list> WITH READ LOCK implementation and keep the latter compatible with global read lock. sql/mdl.h: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. - Deadlock_detection_visitor now has m_table_shares_visited member which allows to support recursive locking for LOCK_open. This is required when deadlock detector inspects waiters graph which contains several edges representing waits for flushes or needs to come through the such edge more than once. sql/mysqld.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mysqld.h: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/sql_base.cc: Changed approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. Thanks to this change MDL deadlock detector can take such waits into account. To implement this/as result of this change: - tdc_wait_for_old_versions() was replaced with tdc_wait_for_old_version() which waits for individual old share to go away and which is called by open_table() after finding out that share is outdated. We don't need to perform back-off before such waiting thanks to the fact that deadlock detector now sees such waits. - As result Open_table_ctx::m_mdl_requests became unnecessary and was removed. We no longer allocate copies of MDL_request objects on MEM_ROOT when MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are in effect. - close_cached_tables() and tdc_wait_for_old_version() share code which implements waiting for share to be flushed - the both use TABLE_SHARE::wait_until_flush() method. Thanks to this close_cached_tables() supports timeouts and has extra parameter for this. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. - In cases when we discover that current connection tries to open tables from different generation we now simply back-off and restart process of opening tables. To support this Open_table_context::OT_REOPEN_TABLES enum element was added. - COND_refresh condition variable became unnecessary and was removed. - mysql_notify_thread_having_shared_lock() no longer wakes up connections waiting for flush as all such connections can be waken up by deadlock detector if necessary. sql/sql_base.h: - close_cached_tables() now has one more parameter - timeout for waiting for table to be flushed. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. Added new OT_REOPEN_TABLES enum element to be used in cases when we need to restart open tables process even in the middle of transaction. - Open_table_ctx::m_mdl_requests became unnecessary and was removed. sql/sql_class.h: Added assert ensuring that we won't use LOCK_open mutex with THD::enter_cond(). Otherwise deadlocks can arise in MDL deadlock detector. sql/sql_parse.cc: Changed FLUSH TABLES <list> WITH READ LOCK to take SNW metadata locks instead of X locks on tables to be flushed. Since we no longer require global IX lock to be taken when SNW locks are taken this makes this statement compatible with FLUSH TABLES WITH READ LOCK statement. Since SNW locks allow other connections to have table opened FLUSH TABLES <list> WITH READ LOCK now has to wait during open_tables() for old version to go away. Such waits can lead to deadlocks which will be detected by MDL deadlock detector which now takes waits for table to be flushed into account. Also adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/sql_yacc.yy: FLUSH TABLES <list> WITH READ LOCK now needs only SNW metadata locks on tables. sql/sys_vars.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/table.cc: Implemented new approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. This change allows to make such waits visible inside of MDL deadlock detector. To do it: - Added list of waiters/Flush_tickets to TABLE_SHARE class. - Changed free_table_share() to postpone freeing of share memory until last waiter goes away and to wake up subscribed waiters. - Added TABLE_SHARE::wait_until_flushed() method which implements subscription to the list of waiters for table to be flushed and waiting for this event. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket). sql/table.h: In order to support new strategy of waiting for table flush (see comment for table.cc for details) added list of waiters/Flush_tickets to TABLE_SHARE class. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket).
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key_COND_rpl_status, key_COND_server_started,
key_delayed_insert_cond, key_delayed_insert_cond_client,
key_item_func_sleep_cond, key_master_info_data_cond,
key_master_info_start_cond, key_master_info_stop_cond,
key_relay_log_info_data_cond, key_relay_log_info_log_space_cond,
key_relay_log_info_start_cond, key_relay_log_info_stop_cond,
key_TABLE_SHARE_cond, key_user_level_lock_cond,
key_COND_thread_count, key_COND_thread_cache, key_COND_flush_thread_cache;
extern PSI_thread_key key_thread_bootstrap, key_thread_delayed_insert,
key_thread_handle_manager, key_thread_kill_server, key_thread_main,
key_thread_one_connection, key_thread_signal_hand;
#ifdef HAVE_MMAP
extern PSI_file_key key_file_map;
#endif /* HAVE_MMAP */
extern PSI_file_key key_file_binlog, key_file_binlog_index, key_file_casetest,
key_file_dbopt, key_file_des_key_file, key_file_ERRMSG, key_select_to_file,
key_file_fileparser, key_file_frm, key_file_global_ddl_log, key_file_load,
key_file_loadfile, key_file_log_event_data, key_file_log_event_info,
key_file_master_info, key_file_misc, key_file_MYSQL_LOG, key_file_partition,
key_file_pid, key_file_relay_log_info, key_file_send_file, key_file_tclog,
key_file_trg, key_file_trn, key_file_init;
void init_server_psi_keys();
#endif /* HAVE_PSI_INTERFACE */
#ifndef __WIN__
extern pthread_t signal_thread;
#endif
#ifdef HAVE_OPENSSL
extern struct st_VioSSLFd * ssl_acceptor_fd;
#endif /* HAVE_OPENSSL */
/*
The following variables were under INNODB_COMPABILITY_HOOKS
*/
extern my_bool opt_large_pages;
extern uint opt_large_page_size;
extern char lc_messages_dir[FN_REFLEN];
extern char *lc_messages_dir_ptr, *log_error_file_ptr;
extern MYSQL_PLUGIN_IMPORT char reg_ext[FN_EXTLEN];
extern MYSQL_PLUGIN_IMPORT uint reg_ext_length;
extern MYSQL_PLUGIN_IMPORT uint lower_case_table_names;
extern MYSQL_PLUGIN_IMPORT bool mysqld_embedded;
extern ulong specialflag;
extern uint mysql_data_home_len;
extern uint mysql_real_data_home_len;
extern const char *mysql_real_data_home_ptr;
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extern ulong thread_handling;
extern MYSQL_PLUGIN_IMPORT char *mysql_data_home;
extern char server_version[SERVER_VERSION_LENGTH];
extern MYSQL_PLUGIN_IMPORT char mysql_real_data_home[];
extern char mysql_unpacked_real_data_home[];
extern MYSQL_PLUGIN_IMPORT struct system_variables global_system_variables;
extern char default_logfile_name[FN_REFLEN];
#define mysql_tmpdir (my_tmpdir(&mysql_tmpdir_list))
extern MYSQL_PLUGIN_IMPORT const key_map key_map_empty;
extern MYSQL_PLUGIN_IMPORT key_map key_map_full; /* Should be threaded as const */
/*
Server mutex locks and condition variables.
*/
extern mysql_mutex_t
LOCK_user_locks, LOCK_status,
LOCK_error_log, LOCK_delayed_insert, LOCK_uuid_generator,
LOCK_delayed_status, LOCK_delayed_create, LOCK_crypt, LOCK_timezone,
LOCK_slave_list, LOCK_active_mi, LOCK_manager, LOCK_global_read_lock,
LOCK_global_system_variables, LOCK_user_conn,
LOCK_prepared_stmt_count, LOCK_error_messages, LOCK_connection_count;
extern MYSQL_PLUGIN_IMPORT mysql_mutex_t LOCK_thread_count;
#ifdef HAVE_OPENSSL
extern mysql_mutex_t LOCK_des_key_file;
#endif
extern mysql_mutex_t LOCK_server_started;
extern mysql_cond_t COND_server_started;
extern mysql_rwlock_t LOCK_grant, LOCK_sys_init_connect, LOCK_sys_init_slave;
extern mysql_rwlock_t LOCK_system_variables_hash;
extern mysql_cond_t COND_thread_count;
Fix for bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". The problem was that FLUSH TABLES <list> WITH READ LOCK which was issued when other connection has acquired global read lock using FLUSH TABLES WITH READ LOCK was blocked and has to wait until global read lock is released. This issue stemmed from the fact that FLUSH TABLES <list> WITH READ LOCK implementation has acquired X metadata locks on tables to be flushed. Since these locks required acquiring of global IX lock this statement was incompatible with global read lock. This patch addresses problem by using SNW metadata type of lock for tables to be flushed by FLUSH TABLES <list> WITH READ LOCK. It is OK to acquire them without global IX lock as long as we won't try to upgrade those locks. Since SNW locks allow concurrent statements using same table FLUSH TABLE <list> WITH READ LOCK now has to wait until old versions of tables to be flushed go away after acquiring metadata locks. Since such waiting can lead to deadlock MDL deadlock detector was extended to take into account waits for flush and resolve such deadlocks. As a bonus code in open_tables() which was responsible for waiting old versions of tables to go away was refactored. Now when we encounter old version of table in open_table() we don't back-off and wait for all old version to go away, but instead wait for this particular table to be flushed. Such approach supported by deadlock detection should reduce number of scenarios in which FLUSH TABLES aborts concurrent multi-statement transactions. Note that active FLUSH TABLES <list> WITH READ LOCK still blocks concurrent FLUSH TABLES WITH READ LOCK statement as the former keeps tables open and thus prevents the latter statement from doing flush. mysql-test/include/handler.inc: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/r/flush.result: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/r/mdl_sync.result: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. mysql-test/suite/perfschema/r/dml_setup_instruments.result: Adjusted test results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/r/server_init.result: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/suite/perfschema/t/server_init.test: Adjusted test and its results after removal of COND_refresh condition variable. mysql-test/t/flush.test: Added test which checks that "flush tables <list> with read lock" is compatible with active "flush tables with read lock" but not vice-versa. This test also covers bug #52044 "FLUSH TABLES WITH READ LOCK and FLUSH TABLES <list> WITH READ LOCK are incompatible". mysql-test/t/kill.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/lock_multi.test: Adjusted test case after changing status which is set when FLUSH TABLES waits for tables to be flushed from "Flushing tables" to "Waiting for table". mysql-test/t/mdl_sync.test: Added scenarios in which wait for table to be flushed causes deadlocks to the coverage of MDL deadlock detector. sql/ha_ndbcluster.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/ha_ndbcluster_binlog.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/lock.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mdl.cc: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. We no longer require global IX metadata lock when acquiring SNW or SNRW locks. Such locks are needed only when metadata locks of these types are upgraded to X locks. This allows to use SNW locks in FLUSH TABLES <list> WITH READ LOCK implementation and keep the latter compatible with global read lock. sql/mdl.h: Now MDL deadlock detector takes into account information about waits for table flushes when searching for deadlock. To implement this change: - Declaration of enum_deadlock_weight and Deadlock_detection_visitor were moved to mdl.h header to make them available to the code in table.cc which implements deadlock detector traversal through edges of waiters graph representing waiting for flush. - Since now MDL_context may wait not only for metadata lock but also for table to be flushed an abstract Wait_for_edge class was introduced. Its descendants MDL_ticket and Flush_ticket incapsulate specifics of inspecting waiters graph when following through edge representing wait of particular type. - Deadlock_detection_visitor now has m_table_shares_visited member which allows to support recursive locking for LOCK_open. This is required when deadlock detector inspects waiters graph which contains several edges representing waits for flushes or needs to come through the such edge more than once. sql/mysqld.cc: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/mysqld.h: Removed COND_refresh condition variable. See comment for sql_base.cc for details. sql/sql_base.cc: Changed approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. Thanks to this change MDL deadlock detector can take such waits into account. To implement this/as result of this change: - tdc_wait_for_old_versions() was replaced with tdc_wait_for_old_version() which waits for individual old share to go away and which is called by open_table() after finding out that share is outdated. We don't need to perform back-off before such waiting thanks to the fact that deadlock detector now sees such waits. - As result Open_table_ctx::m_mdl_requests became unnecessary and was removed. We no longer allocate copies of MDL_request objects on MEM_ROOT when MYSQL_OPEN_FORCE_SHARED/SHARED_HIGH_PRIO flags are in effect. - close_cached_tables() and tdc_wait_for_old_version() share code which implements waiting for share to be flushed - the both use TABLE_SHARE::wait_until_flush() method. Thanks to this close_cached_tables() supports timeouts and has extra parameter for this. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. - In cases when we discover that current connection tries to open tables from different generation we now simply back-off and restart process of opening tables. To support this Open_table_context::OT_REOPEN_TABLES enum element was added. - COND_refresh condition variable became unnecessary and was removed. - mysql_notify_thread_having_shared_lock() no longer wakes up connections waiting for flush as all such connections can be waken up by deadlock detector if necessary. sql/sql_base.h: - close_cached_tables() now has one more parameter - timeout for waiting for table to be flushed. - Open_table_context::OT_MDL_CONFLICT enum element was renamed to OT_CONFLICT as it is now also used in cases when back-off is required to resolve deadlock caused by waiting for flush and not metadata lock. Added new OT_REOPEN_TABLES enum element to be used in cases when we need to restart open tables process even in the middle of transaction. - Open_table_ctx::m_mdl_requests became unnecessary and was removed. sql/sql_class.h: Added assert ensuring that we won't use LOCK_open mutex with THD::enter_cond(). Otherwise deadlocks can arise in MDL deadlock detector. sql/sql_parse.cc: Changed FLUSH TABLES <list> WITH READ LOCK to take SNW metadata locks instead of X locks on tables to be flushed. Since we no longer require global IX lock to be taken when SNW locks are taken this makes this statement compatible with FLUSH TABLES WITH READ LOCK statement. Since SNW locks allow other connections to have table opened FLUSH TABLES <list> WITH READ LOCK now has to wait during open_tables() for old version to go away. Such waits can lead to deadlocks which will be detected by MDL deadlock detector which now takes waits for table to be flushed into account. Also adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/sql_yacc.yy: FLUSH TABLES <list> WITH READ LOCK now needs only SNW metadata locks on tables. sql/sys_vars.cc: Adjusted code after adding one more parameter for close_cached_tables() call - timeout for waiting for table to be flushed. sql/table.cc: Implemented new approach to how threads are waiting for table to be flushed. Now thread that wants to wait for old table to go away subscribes for notification by adding Flush_ticket to table's share and waits using MDL_context::m_wait object. Once table gets flushed (i.e. all tables are closed and table share is ready to be destroyed) all such waiters are notified individually. This change allows to make such waits visible inside of MDL deadlock detector. To do it: - Added list of waiters/Flush_tickets to TABLE_SHARE class. - Changed free_table_share() to postpone freeing of share memory until last waiter goes away and to wake up subscribed waiters. - Added TABLE_SHARE::wait_until_flushed() method which implements subscription to the list of waiters for table to be flushed and waiting for this event. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket). sql/table.h: In order to support new strategy of waiting for table flush (see comment for table.cc for details) added list of waiters/Flush_tickets to TABLE_SHARE class. Implemented interface which allows to expose waits for flushes to MDL deadlock detector: - Introduced Flush_ticket class a descendant of Wait_for_edge class. - Added TABLE_SHARE::find_deadlock() method which allows deadlock detector to find out what contexts are still using old version of table in question (i.e. to find out what contexts are waited for by owner of Flush_ticket).
2010-07-27 15:34:58 +02:00
extern mysql_cond_t COND_manager;
extern mysql_cond_t COND_global_read_lock;
extern int32 thread_running;
extern my_atomic_rwlock_t thread_running_lock;
extern char *opt_ssl_ca, *opt_ssl_capath, *opt_ssl_cert, *opt_ssl_cipher,
*opt_ssl_key;
extern MYSQL_PLUGIN_IMPORT pthread_key(THD*, THR_THD);
/**
only options that need special treatment in get_one_option() deserve
to be listed below
*/
enum options_mysqld
{
OPT_to_set_the_start_number=256,
OPT_BIND_ADDRESS,
OPT_BINLOG_DO_DB,
OPT_BINLOG_FORMAT,
OPT_BINLOG_IGNORE_DB,
OPT_BIN_LOG,
OPT_BOOTSTRAP,
OPT_CONSOLE,
OPT_DEBUG_SYNC_TIMEOUT,
OPT_DELAY_KEY_WRITE_ALL,
OPT_ISAM_LOG,
OPT_KEY_BUFFER_SIZE,
OPT_KEY_CACHE_AGE_THRESHOLD,
OPT_KEY_CACHE_BLOCK_SIZE,
OPT_KEY_CACHE_DIVISION_LIMIT,
OPT_LOWER_CASE_TABLE_NAMES,
OPT_ONE_THREAD,
OPT_POOL_OF_THREADS,
OPT_REPLICATE_DO_DB,
OPT_REPLICATE_DO_TABLE,
OPT_REPLICATE_IGNORE_DB,
OPT_REPLICATE_IGNORE_TABLE,
OPT_REPLICATE_REWRITE_DB,
OPT_REPLICATE_WILD_DO_TABLE,
OPT_REPLICATE_WILD_IGNORE_TABLE,
OPT_SAFE,
OPT_SERVER_ID,
OPT_SKIP_HOST_CACHE,
OPT_SKIP_LOCK,
OPT_SKIP_NEW,
OPT_SKIP_PRIOR,
OPT_SKIP_RESOLVE,
OPT_SKIP_STACK_TRACE,
OPT_SKIP_SYMLINKS,
OPT_SLOW_QUERY_LOG,
OPT_SSL_CA,
OPT_SSL_CAPATH,
OPT_SSL_CERT,
OPT_SSL_CIPHER,
OPT_SSL_KEY,
OPT_UPDATE_LOG,
OPT_WANT_CORE,
OPT_ENGINE_CONDITION_PUSHDOWN,
OPT_LOG_ERROR,
OPT_AUTOCOMMIT
};
/**
Query type constants.
QT_ORDINARY -- ordinary SQL query.
QT_IS -- SQL query to be shown in INFORMATION_SCHEMA (in utf8 and without
character set introducers).
*/
enum enum_query_type
{
QT_ORDINARY,
QT_IS
};
/* query_id */
typedef int64 query_id_t;
extern query_id_t global_query_id;
extern my_atomic_rwlock_t global_query_id_lock;
void unireg_end(void) __attribute__((noreturn));
/* increment query_id and return it. */
inline query_id_t next_query_id()
{
query_id_t id;
my_atomic_rwlock_wrlock(&global_query_id_lock);
id= my_atomic_add64(&global_query_id, 1);
my_atomic_rwlock_wrunlock(&global_query_id_lock);
return (id+1);
}
inline query_id_t get_query_id()
{
query_id_t id;
my_atomic_rwlock_wrlock(&global_query_id_lock);
id= my_atomic_load64(&global_query_id);
my_atomic_rwlock_wrunlock(&global_query_id_lock);
return id;
}
/*
TODO: Replace this with an inline function.
*/
#ifndef EMBEDDED_LIBRARY
extern "C" void unireg_abort(int exit_code) __attribute__((noreturn));
#else
extern "C" void unireg_clear(int exit_code);
#define unireg_abort(exit_code) do { unireg_clear(exit_code); DBUG_RETURN(exit_code); } while(0)
#endif
inline void table_case_convert(char * name, uint length)
{
if (lower_case_table_names)
files_charset_info->cset->casedn(files_charset_info,
name, length, name, length);
}
inline ulong sql_rnd_with_mutex()
{
mysql_mutex_lock(&LOCK_thread_count);
ulong tmp=(ulong) (my_rnd(&sql_rand) * 0xffffffff); /* make all bits random */
mysql_mutex_unlock(&LOCK_thread_count);
return tmp;
}
inline int32
inc_thread_running()
{
int32 num_thread_running;
my_atomic_rwlock_wrlock(&thread_running_lock);
num_thread_running= my_atomic_add32(&thread_running, 1);
my_atomic_rwlock_wrunlock(&thread_running_lock);
return (num_thread_running+1);
}
inline int32
dec_thread_running()
{
int32 num_thread_running;
my_atomic_rwlock_wrlock(&thread_running_lock);
num_thread_running= my_atomic_add32(&thread_running, -1);
my_atomic_rwlock_wrunlock(&thread_running_lock);
return (num_thread_running-1);
}
inline int32
get_thread_running()
{
int32 num_thread_running;
my_atomic_rwlock_wrlock(&thread_running_lock);
num_thread_running= my_atomic_load32(&thread_running);
my_atomic_rwlock_wrunlock(&thread_running_lock);
return num_thread_running;
}
#if defined(MYSQL_DYNAMIC_PLUGIN) && defined(_WIN32)
extern "C" THD *_current_thd_noinline();
#define _current_thd() _current_thd_noinline()
#else
extern pthread_key(THD*, THR_THD);
inline THD *_current_thd(void)
{
return my_pthread_getspecific_ptr(THD*,THR_THD);
}
#endif
#define current_thd _current_thd()
#endif /* MYSQLD_INCLUDED */