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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 18:07:14 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-04 18:07:14 +0000 |
commit | a175314c3e5827eb193872241446f2f8f5c9d33c (patch) | |
tree | cd3d60ca99ae00829c52a6ca79150a5b6e62528b /sql/session_tracker.h | |
parent | Initial commit. (diff) | |
download | mariadb-10.5-upstream/1%10.5.12.tar.xz mariadb-10.5-upstream/1%10.5.12.zip |
Adding upstream version 1:10.5.12.upstream/1%10.5.12upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | sql/session_tracker.h | 498 |
1 files changed, 498 insertions, 0 deletions
diff --git a/sql/session_tracker.h b/sql/session_tracker.h new file mode 100644 index 00000000..c78778ac --- /dev/null +++ b/sql/session_tracker.h @@ -0,0 +1,498 @@ +#ifndef SESSION_TRACKER_INCLUDED +#define SESSION_TRACKER_INCLUDED + +/* Copyright (c) 2015, Oracle and/or its affiliates. All rights reserved. + Copyright (c) 2016, 2017, MariaDB Corporation. + + 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 */ + +#include "m_string.h" +#include "thr_lock.h" +#include "sql_hset.h" + +#ifndef EMBEDDED_LIBRARY +/* forward declarations */ +class THD; +class set_var; +class String; +class user_var_entry; + + +enum enum_session_tracker +{ + SESSION_SYSVARS_TRACKER, /* Session system variables */ + CURRENT_SCHEMA_TRACKER, /* Current schema */ + SESSION_STATE_CHANGE_TRACKER, + TRANSACTION_INFO_TRACKER, /* Transaction state */ +#ifdef USER_VAR_TRACKING + USER_VARIABLES_TRACKER, +#endif // USER_VAR_TRACKING + SESSION_TRACKER_END /* must be the last */ +}; + +/** + State_tracker + + An abstract class that defines the interface for any of the server's + 'session state change tracker'. A tracker, however, is a sub- class of + this class which takes care of tracking the change in value of a part- + icular session state type and thus defines various methods listed in this + interface. The change information is later serialized and transmitted to + the client through protocol's OK packet. + + Tracker system variables :- + A tracker is normally mapped to a system variable. So in order to enable, + disable or modify the sub-entities of a tracker, the user needs to modify + the respective system variable either through SET command or via command + line option. As required in system variable handling, this interface also + includes two functions to help in the verification of the supplied value + (ON_UPDATE) of the tracker system variable, namely - update(). +*/ + +class State_tracker +{ +protected: + /** + Is tracking enabled for a particular session state type ? + + @note: it is a cache of the corresponding thd->variables.session_track_xxx + variable + */ + bool m_enabled; + + void set_changed(THD *thd); + +private: + /** Has the session state type changed ? */ + bool m_changed; + +public: + virtual ~State_tracker() {} + + /** Getters */ + bool is_enabled() const + { return m_enabled; } + + bool is_changed() const + { return m_changed; } + + void reset_changed() { m_changed= false; } + + /** + Called by THD::init() when new connection is being created + + We may inherit m_changed from previous connection served by this THD if + connection was broken or client didn't have session tracking capability. + Thus we have to reset it here. + */ + virtual bool enable(THD *thd) + { + reset_changed(); + return update(thd, 0); + } + + /** To be invoked when the tracker's system variable is updated (ON_UPDATE).*/ + virtual bool update(THD *thd, set_var *var)= 0; + + /** Store changed data into the given buffer. */ + virtual bool store(THD *thd, String *buf)= 0; + + /** Mark the entity as changed. */ + void mark_as_changed(THD *thd) { if (is_enabled()) set_changed(thd); } +}; + + +/** + Session_sysvars_tracker + + This is a tracker class that enables & manages the tracking of session + system variables. It internally maintains a hash of user supplied variable + references and a boolean field to store if the variable was changed by the + last statement. +*/ + +class Session_sysvars_tracker: public State_tracker +{ + struct sysvar_node_st { + sys_var *m_svar; + bool *test_load; + bool m_changed; + }; + + class vars_list + { + /** + Registered system variables. (@@session_track_system_variables) + A hash to store the name of all the system variables specified by the + user. + */ + HASH m_registered_sysvars; + /** + If TRUE then we want to check all session variable. + */ + bool track_all; + void init() + { + my_hash_init(PSI_INSTRUMENT_ME, &m_registered_sysvars, &my_charset_bin, + 0, 0, 0, (my_hash_get_key) sysvars_get_key, my_free, + HASH_UNIQUE | (mysqld_server_initialized ? HASH_THREAD_SPECIFIC : 0)); + } + void free_hash() + { + DBUG_ASSERT(my_hash_inited(&m_registered_sysvars)); + my_hash_free(&m_registered_sysvars); + } + + sysvar_node_st *search(const sys_var *svar) + { + return reinterpret_cast<sysvar_node_st*>( + my_hash_search(&m_registered_sysvars, + reinterpret_cast<const uchar*>(&svar), + sizeof(sys_var*))); + } + + sysvar_node_st *at(ulong i) + { + DBUG_ASSERT(i < m_registered_sysvars.records); + return reinterpret_cast<sysvar_node_st*>( + my_hash_element(&m_registered_sysvars, i)); + } + public: + vars_list(): track_all(false) { init(); } + ~vars_list() { if (my_hash_inited(&m_registered_sysvars)) free_hash(); } + void deinit() { free_hash(); } + + sysvar_node_st *insert_or_search(const sys_var *svar) + { + sysvar_node_st *res= search(svar); + if (!res) + { + if (track_all) + { + insert(svar); + return search(svar); + } + } + return res; + } + + bool insert(const sys_var *svar); + void reinit(); + void reset(); + inline bool is_enabled() + { + return track_all || m_registered_sysvars.records; + } + void copy(vars_list* from, THD *thd); + bool parse_var_list(THD *thd, LEX_STRING var_list, bool throw_error, + CHARSET_INFO *char_set); + bool construct_var_list(char *buf, size_t buf_len); + bool store(THD *thd, String *buf); + }; + /** + Two objects of vars_list type are maintained to manage + various operations. + */ + vars_list orig_list; + bool m_parsed; + +public: + void init(THD *thd); + void deinit(THD *thd); + bool enable(THD *thd); + bool update(THD *thd, set_var *var); + bool store(THD *thd, String *buf); + void mark_as_changed(THD *thd, const sys_var *var); + void deinit() { orig_list.deinit(); } + /* callback */ + static uchar *sysvars_get_key(const char *entry, size_t *length, + my_bool not_used __attribute__((unused))); + + friend bool sysvartrack_global_update(THD *thd, char *str, size_t len); +}; + + +bool sysvartrack_validate_value(THD *thd, const char *str, size_t len); +bool sysvartrack_global_update(THD *thd, char *str, size_t len); + + +/** + Current_schema_tracker, + + This is a tracker class that enables & manages the tracking of current + schema for a particular connection. +*/ + +class Current_schema_tracker: public State_tracker +{ +public: + bool update(THD *thd, set_var *var); + bool store(THD *thd, String *buf); +}; + + +/* + Session_state_change_tracker + + This is a boolean tracker class that will monitor any change that contributes + to a session state change. + Attributes that contribute to session state change include: + - Successful change to System variables + - User defined variables assignments + - temporary tables created, altered or deleted + - prepared statements added or removed + - change in current database + - change of current role +*/ + +class Session_state_change_tracker: public State_tracker +{ +public: + bool update(THD *thd, set_var *var); + bool store(THD *thd, String *buf); +}; + + +/* + Transaction_state_tracker +*/ + +/** + Transaction state (no transaction, transaction active, work attached, etc.) +*/ +enum enum_tx_state { + TX_EMPTY = 0, ///< "none of the below" + TX_EXPLICIT = 1, ///< an explicit transaction is active + TX_IMPLICIT = 2, ///< an implicit transaction is active + TX_READ_TRX = 4, ///< transactional reads were done + TX_READ_UNSAFE = 8, ///< non-transaction reads were done + TX_WRITE_TRX = 16, ///< transactional writes were done + TX_WRITE_UNSAFE = 32, ///< non-transactional writes were done + TX_STMT_UNSAFE = 64, ///< "unsafe" (non-deterministic like UUID()) stmts + TX_RESULT_SET = 128, ///< result set was sent + TX_WITH_SNAPSHOT= 256, ///< WITH CONSISTENT SNAPSHOT was used + TX_LOCKED_TABLES= 512 ///< LOCK TABLES is active +}; + + +/** + Transaction access mode +*/ +enum enum_tx_read_flags { + TX_READ_INHERIT = 0, ///< not explicitly set, inherit session.tx_read_only + TX_READ_ONLY = 1, ///< START TRANSACTION READ ONLY, or tx_read_only=1 + TX_READ_WRITE = 2, ///< START TRANSACTION READ WRITE, or tx_read_only=0 +}; + + +/** + Transaction isolation level +*/ +enum enum_tx_isol_level { + TX_ISOL_INHERIT = 0, ///< not explicitly set, inherit session.tx_isolation + TX_ISOL_UNCOMMITTED = 1, + TX_ISOL_COMMITTED = 2, + TX_ISOL_REPEATABLE = 3, + TX_ISOL_SERIALIZABLE= 4 +}; + + +/** + Transaction tracking level +*/ +enum enum_session_track_transaction_info { + TX_TRACK_NONE = 0, ///< do not send tracker items on transaction info + TX_TRACK_STATE = 1, ///< track transaction status + TX_TRACK_CHISTICS = 2 ///< track status and characteristics +}; + + +/** + This is a tracker class that enables & manages the tracking of + current transaction info for a particular connection. +*/ + +class Transaction_state_tracker : public State_tracker +{ + /** Helper function: turn table info into table access flag */ + enum_tx_state calc_trx_state(THD *thd, thr_lock_type l, bool has_trx); +public: + + bool enable(THD *thd) + { + m_enabled= false; + tx_changed= TX_CHG_NONE; + tx_curr_state= TX_EMPTY; + tx_reported_state= TX_EMPTY; + tx_read_flags= TX_READ_INHERIT; + tx_isol_level= TX_ISOL_INHERIT; + return State_tracker::enable(thd); + } + + bool update(THD *thd, set_var *var); + bool store(THD *thd, String *buf); + + /** Change transaction characteristics */ + void set_read_flags(THD *thd, enum enum_tx_read_flags flags); + void set_isol_level(THD *thd, enum enum_tx_isol_level level); + + /** Change transaction state */ + void clear_trx_state(THD *thd, uint clear); + void add_trx_state(THD *thd, uint add); + void inline add_trx_state(THD *thd, thr_lock_type l, bool has_trx) + { + add_trx_state(thd, calc_trx_state(thd, l, has_trx)); + } + void add_trx_state_from_thd(THD *thd); + void end_trx(THD *thd); + + +private: + enum enum_tx_changed { + TX_CHG_NONE = 0, ///< no changes from previous stmt + TX_CHG_STATE = 1, ///< state has changed from previous stmt + TX_CHG_CHISTICS = 2 ///< characteristics have changed from previous stmt + }; + + /** any trackable changes caused by this statement? */ + uint tx_changed; + + /** transaction state */ + uint tx_curr_state, tx_reported_state; + + /** r/w or r/o set? session default? */ + enum enum_tx_read_flags tx_read_flags; + + /** isolation level */ + enum enum_tx_isol_level tx_isol_level; + + inline void update_change_flags(THD *thd) + { + tx_changed &= uint(~TX_CHG_STATE); + tx_changed |= (tx_curr_state != tx_reported_state) ? TX_CHG_STATE : 0; + if (tx_changed != TX_CHG_NONE) + set_changed(thd); + } +}; + +#define TRANSACT_TRACKER(X) \ + do { if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) \ + thd->session_tracker.transaction_info.X; } while(0) + + +/** + User_variables_tracker + + This is a tracker class that enables & manages the tracking of user variables. +*/ + +#ifdef USER_VAR_TRACKING +class User_variables_tracker: public State_tracker +{ + Hash_set<const user_var_entry> m_changed_user_variables; +public: + User_variables_tracker(): + m_changed_user_variables(PSI_INSTRUMENT_ME, &my_charset_bin, 0, 0, + sizeof(const user_var_entry*), 0, 0, HASH_UNIQUE | + mysqld_server_initialized ? HASH_THREAD_SPECIFIC : 0) {} + bool update(THD *thd, set_var *var); + bool store(THD *thd, String *buf); + void mark_as_changed(THD *thd, const user_var_entry *var) + { + if (is_enabled()) + { + m_changed_user_variables.insert(var); + set_changed(thd); + } + } + void deinit() { m_changed_user_variables.~Hash_set(); } +}; +#endif // USER_VAR_TRACKING + + +/** + Session_tracker + + This class holds an object each for all tracker classes and provides + methods necessary for systematic detection and generation of session + state change information. +*/ + +class Session_tracker +{ + State_tracker *m_trackers[SESSION_TRACKER_END]; + + /* The following two functions are private to disable copying. */ + Session_tracker(Session_tracker const &other) + { + DBUG_ASSERT(FALSE); + } + Session_tracker& operator= (Session_tracker const &rhs) + { + DBUG_ASSERT(FALSE); + return *this; + } + +public: + Current_schema_tracker current_schema; + Session_state_change_tracker state_change; + Transaction_state_tracker transaction_info; + Session_sysvars_tracker sysvars; +#ifdef USER_VAR_TRACKING + User_variables_tracker user_variables; +#endif // USER_VAR_TRACKING + + Session_tracker() + { + m_trackers[SESSION_SYSVARS_TRACKER]= &sysvars; + m_trackers[CURRENT_SCHEMA_TRACKER]= ¤t_schema; + m_trackers[SESSION_STATE_CHANGE_TRACKER]= &state_change; + m_trackers[TRANSACTION_INFO_TRACKER]= &transaction_info; +#ifdef USER_VAR_TRACKING + m_trackers[USER_VARIABLES_TRACKER]= &user_variables; +#endif // USER_VAR_TRACKING + } + + void enable(THD *thd) + { + for (int i= 0; i < SESSION_TRACKER_END; i++) + m_trackers[i]->enable(thd); + } + + void store(THD *thd, String *main_buf); +}; + + +int session_tracker_init(); +#else + +#define TRANSACT_TRACKER(X) do{}while(0) + +class Session_tracker +{ + class Dummy_tracker + { + public: + void mark_as_changed(THD *thd) {} + void mark_as_changed(THD *thd, const sys_var *var) {} + }; +public: + Dummy_tracker current_schema; + Dummy_tracker state_change; + Dummy_tracker sysvars; +}; + +#endif //EMBEDDED_LIBRARY + +#endif /* SESSION_TRACKER_INCLUDED */ |