Adding upstream version 1:10.11.6.upstream/1%10.11.6upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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..5715b583
--- /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() = default;
+
+  /** 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]= &current_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 */