Merge 10.1 into 10.2

mysql-test/suite/roles/set_default_role_for.result

@@ -14,7 +14,7 @@ set default role role_a for user_a@localhost;
 set default role invalid_role for user_a@localhost;
 ERROR OP000: Invalid role specification `invalid_role`
 set default role role_b for user_a@localhost;
-ERROR OP000: Invalid role specification `role_b`
+ERROR OP000: User `user_a@localhost` has not been granted role `role_b`
 set default role role_b for user_b@localhost;
 show grants;
 Grants for user_a@localhost
@@ -36,7 +36,7 @@ user	host	default_role
 user_a	localhost	role_a
 user_b	localhost	role_b
 set default role role_b for current_user;
-ERROR OP000: Invalid role specification `role_b`
+ERROR OP000: User `user_a@localhost` has not been granted role `role_b`
 show grants;
 Grants for user_b@localhost
 GRANT role_b TO 'user_b'@'localhost'

mysql-test/suite/roles/set_default_role_invalid.result

@@ -38,3 +38,90 @@ ERROR 42000: SELECT command denied to user 'test_user'@'localhost' for table 'us
 drop role test_role;
 drop role not_granted_role;
 drop user test_user@localhost;
+#
+# MDEV-22312: Bad error message for SET DEFAULT ROLE when user account
+#             is not granted the role
+#
+CREATE USER a;
+CREATE USER b;
+CREATE ROLE r1;
+CREATE ROLE r2;
+SET DEFAULT ROLE r1 FOR a;
+ERROR OP000: User `a@%` has not been granted role `r1`
+GRANT r1 TO b;
+GRANT r2 TO b;
+SET DEFAULT ROLE r1 FOR b;
+# Change user b
+SELECT CURRENT_ROLE;
+CURRENT_ROLE
+r1
+SET ROLE r2;
+SELECT CURRENT_ROLE;
+CURRENT_ROLE
+r2
+SET DEFAULT ROLE r1 FOR a;
+ERROR 42000: Access denied for user 'b'@'%' to database 'mysql'
+SET DEFAULT ROLE r2;
+# Change user root (session 1: select_priv to b)
+GRANT SELECT ON mysql.* TO b;
+# Change user b (session 1: select_priv)
+SHOW GRANTS FOR b;
+Grants for b@%
+GRANT r1 TO 'b'@'%'
+GRANT r2 TO 'b'@'%'
+GRANT USAGE ON *.* TO 'b'@'%'
+GRANT SELECT ON `mysql`.* TO 'b'@'%'
+SET DEFAULT ROLE r1 FOR a;
+ERROR 42000: Access denied for user 'b'@'%' to database 'mysql'
+SELECT CURRENT_ROLE;
+CURRENT_ROLE
+r2
+SET DEFAULT ROLE NONE;
+SELECT CURRENT_ROLE;
+CURRENT_ROLE
+r2
+SET DEFAULT ROLE current_role FOR current_user;
+SET DEFAULT ROLE invalid_role;
+ERROR OP000: Invalid role specification `invalid_role`
+SET DEFAULT ROLE invalid_role FOR a;
+ERROR 42000: Access denied for user 'b'@'%' to database 'mysql'
+SET DEFAULT ROLE none FOR a;
+ERROR 42000: Access denied for user 'b'@'%' to database 'mysql'
+# Change user root (session 2: adding update_priv to user b)
+GRANT UPDATE ON mysql.* TO b;
+# Change user b
+SHOW GRANTS FOR b;
+Grants for b@%
+GRANT r1 TO 'b'@'%'
+GRANT r2 TO 'b'@'%'
+GRANT USAGE ON *.* TO 'b'@'%'
+GRANT SELECT, UPDATE ON `mysql`.* TO 'b'@'%'
+SET DEFAULT ROLE r1 FOR a;
+ERROR OP000: User `a@%` has not been granted role `r1`
+SET DEFAULT ROLE invalid_role;
+ERROR OP000: Invalid role specification `invalid_role`
+SET DEFAULT ROLE invalid_role FOR a;
+ERROR OP000: Invalid role specification `invalid_role`
+SET DEFAULT ROLE none FOR a;
+# Change user root (session 3: Grant role to user a)
+GRANT r1 TO a;
+SET DEFAULT ROLE r1 FOR a;
+# Change user a (verify session 3)
+SELECT CURRENT_ROLE;
+CURRENT_ROLE
+r1
+SET DEFAULT ROLE None;
+# Change user b (session 3: role granted to user a)
+SET DEFAULT ROLE r1 FOR a;
+SET DEFAULT ROLE r2 FOR a;
+ERROR OP000: User `a@%` has not been granted role `r2`
+SET DEFAULT ROLE invalid_role;
+ERROR OP000: Invalid role specification `invalid_role`
+SET DEFAULT ROLE invalid_role FOR a;
+ERROR OP000: Invalid role specification `invalid_role`
+SELECT user, host, default_role FROM mysql.user where user='a' or user='b';
+user	host	default_role
+a	%	r1
+b	%	r2
+DROP ROLE r1, r2;
+DROP USER a, b;

mysql-test/suite/roles/set_default_role_invalid.test

@@ -60,3 +60,110 @@ change_user 'root';
 drop role test_role;
 drop role not_granted_role;
 drop user test_user@localhost;
+
+--echo #
+--echo # MDEV-22312: Bad error message for SET DEFAULT ROLE when user account
+--echo #             is not granted the role
+--echo #
+
+CREATE USER a;
+CREATE USER b;
+CREATE ROLE r1;
+CREATE ROLE r2;
+# Role has not been granted to user a, but the role is visible to current_user
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE r1 FOR a;
+# Granting roles to user b
+GRANT r1 TO b;
+GRANT r2 TO b;
+# After granting the role, role can be set as default
+SET DEFAULT ROLE r1 FOR b;
+
+--echo # Change user b
+change_user b;
+SELECT CURRENT_ROLE;
+SET ROLE r2;
+SELECT CURRENT_ROLE;
+# User b has no UPDATE_PRIV for mysql.user
+--error ER_DBACCESS_DENIED_ERROR
+SET DEFAULT ROLE r1 FOR a;
+SET DEFAULT ROLE r2;
+
+--echo # Change user root (session 1: select_priv to b)
+change_user root;
+# Let's grant select_priv to user b
+GRANT SELECT ON mysql.* TO b;
+
+--echo # Change user b (session 1: select_priv)
+change_user b;
+SHOW GRANTS FOR b;
+# User must have update_priv before setting the role
+--error ER_DBACCESS_DENIED_ERROR
+SET DEFAULT ROLE r1 FOR a;
+# Testing the `CURRENT_ROLE` as a special case
+SELECT CURRENT_ROLE;
+SET DEFAULT ROLE NONE;
+SELECT CURRENT_ROLE;
+SET DEFAULT ROLE current_role FOR current_user;
+# Testing of non-existing role
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE invalid_role;
+# Testing of non-existing role for different user
+--error ER_DBACCESS_DENIED_ERROR
+SET DEFAULT ROLE invalid_role FOR a;
+# Testing the `None` role for different user
+-- error ER_DBACCESS_DENIED_ERROR
+SET DEFAULT ROLE none FOR a;
+
+--echo # Change user root (session 2: adding update_priv to user b)
+change_user root;
+# update_priv are enough
+GRANT UPDATE ON mysql.* TO b;
+
+--echo # Change user b
+change_user b;
+SHOW GRANTS FOR b;
+# In all tests in session user a has not been granted the role
+# Testing setting role for different user, should fail with new error
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE r1 FOR a;
+# Testing of non-existing role
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE invalid_role;
+# Testing of non-existing role for different user with update_priv
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE invalid_role FOR a;
+# Testing the `None` role for different user with update_priv
+SET DEFAULT ROLE none FOR a;
+
+--echo # Change user root (session 3: Grant role to user a)
+change_user root;
+# After granting the privilege for a, user b can set default role
+GRANT r1 TO a;
+SET DEFAULT ROLE r1 FOR a;
+
+--echo # Change user a (verify session 3)
+change_user a;
+SELECT CURRENT_ROLE;
+SET DEFAULT ROLE None;
+
+--echo # Change user b (session 3: role granted to user a)
+change_user b;
+# This should set role because b has update_priv
+SET DEFAULT ROLE r1 FOR a;
+# Testing non-granted role r2 still should fail
+-- error ER_INVALID_ROLE
+SET DEFAULT ROLE r2 FOR a;
+# Testing of non-existing role
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE invalid_role;
+# Testing of non-existing role for different user
+--error ER_INVALID_ROLE
+SET DEFAULT ROLE invalid_role FOR a;
+
+# Clear the workspace
+change_user root;
+--sorted_result
+SELECT user, host, default_role FROM mysql.user where user='a' or user='b';
+DROP ROLE r1, r2;
+DROP USER a, b;

mysql-test/suite/roles/set_role-recursive.result

@@ -66,7 +66,7 @@ Grants for test_user@localhost
 GRANT USAGE ON *.* TO 'test_user'@'localhost'
 GRANT test_role1 TO 'test_user'@'localhost'
 set role test_role2;
-ERROR OP000: Invalid role specification `test_role2`
+ERROR OP000: User `test_user@localhost` has not been granted role `test_role2`
 select current_user(), current_role();
 current_user()	current_role()
 test_user@localhost	NULL

sql/item_xmlfunc.cc

@@ -815,7 +815,6 @@ String *Item_nodeset_func_attributebyname::val_nodeset(String *nodeset)
 String *Item_nodeset_func_predicate::val_nodeset(String *str)
 {
   Item_nodeset_func *nodeset_func= (Item_nodeset_func*) args[0];
-  Item_func *comp_func= (Item_func*)args[1];
   uint pos= 0, size;
   prepare(str);
   size= (uint)(fltend - fltbeg);
@@ -825,7 +824,7 @@ String *Item_nodeset_func_predicate::val_nodeset(String *str)
     ((XPathFilter*)(&nodeset_func->context_cache))->append_element(flt->num,
                                                                    flt->pos,
                                                                    size);
-    if (comp_func->val_int())
+    if (args[1]->val_int())
       ((XPathFilter*)str)->append_element(flt->num, pos++);
   }
   return str;

sql/set_var.cc

@@ -971,8 +971,17 @@ int set_var_default_role::check(THD *thd)
 {
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   real_user= get_current_user(thd, user);
-  int status= acl_check_set_default_role(thd, real_user->host.str, real_user->user.str);
-  return status;
+  real_role= role.str;
+  if (role.str == current_role.str)
+  {
+    if (!thd->security_ctx->priv_role[0])
+      real_role= "NONE";
+    else
+      real_role= thd->security_ctx->priv_role;
+  }
+
+  return acl_check_set_default_role(thd, real_user->host.str,
+                                    real_user->user.str, real_role);
 #else
   return 0;
 #endif
@@ -983,7 +992,8 @@ int set_var_default_role::update(THD *thd)
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
   Reprepare_observer *save_reprepare_observer= thd->m_reprepare_observer;
   thd->m_reprepare_observer= 0;
-  int res= acl_set_default_role(thd, real_user->host.str, real_user->user.str, role.str);
+  int res= acl_set_default_role(thd, real_user->host.str, real_user->user.str,
+                                real_role);
   thd->m_reprepare_observer= save_reprepare_observer;
   return res;
 #else

sql/set_var.h

@@ -350,6 +350,7 @@ class set_var_default_role: public set_var_base
 {
   LEX_USER *user, *real_user;
   LEX_STRING role;
+  const char *real_role;
 public:
   set_var_default_role(LEX_USER *user_arg, LEX_STRING role_arg) :
     user(user_arg), role(role_arg) {}

sql/sql_acl.cc

 /* Copyright (c) 2000, 2018, Oracle and/or its affiliates.
-   Copyright (c) 2009, 2018, MariaDB
+   Copyright (c) 2009, 2020, MariaDB
 
    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
@@ -201,7 +201,6 @@ LEX_STRING current_user= { C_STRING_WITH_LEN("*current_user") };
 LEX_STRING current_role= { C_STRING_WITH_LEN("*current_role") };
 LEX_STRING current_user_and_current_role= { C_STRING_WITH_LEN("*current_user_and_current_role") };
 
-
 #ifndef NO_EMBEDDED_ACCESS_CHECKS
 static plugin_ref old_password_plugin;
 #endif
@@ -2618,8 +2617,43 @@ bool acl_getroot(Security_context *sctx, char *user, char *host,
   DBUG_RETURN(res);
 }
 
-static int check_user_can_set_role(const char *user, const char *host,
-                      const char *ip, const char *rolename, ulonglong *access)
+static int check_role_is_granted_callback(ACL_USER_BASE *grantee, void *data)
+{
+  LEX_CSTRING *rolename= static_cast<LEX_CSTRING *>(data);
+  if (rolename->length == grantee->user.length &&
+      !strcmp(rolename->str, grantee->user.str))
+    return -1; // End search, we've found our role.
+
+  /* Keep looking, we haven't found our role yet. */
+  return 0;
+}
+
+/*
+  unlike find_user_exact and find_user_wild,
+  this function finds anonymous users too, it's when a
+  user is not empty, but priv_user (acl_user->user) is empty.
+*/
+static ACL_USER *find_user_or_anon(const char *host, const char *user, const char *ip)
+{
+  ACL_USER *result= NULL;
+  mysql_mutex_assert_owner(&acl_cache->lock);
+  for (uint i=0; i < acl_users.elements; i++)
+  {
+    ACL_USER *acl_user_tmp= dynamic_element(&acl_users, i, ACL_USER*);
+    if ((!acl_user_tmp->user.str ||
+         !strcmp(user, acl_user_tmp->user.str)) &&
+         compare_hostname(&acl_user_tmp->host, host, ip))
+    {
+      result= acl_user_tmp;
+      break;
+    }
+  }
+  return result;
+}
+
+static int check_user_can_set_role(THD *thd, const char *user, const char *host,
+                                   const char *ip, const char *rolename,
+                                   ulonglong *access)
 {
   ACL_ROLE *role;
   ACL_USER_BASE *acl_user_base;
@@ -2636,10 +2670,7 @@ static int check_user_can_set_role(const char *user, const char *host,
     /* get the current user */
     acl_user= find_user_wild(host, user, ip);
     if (acl_user == NULL)
-    {
-      my_error(ER_INVALID_CURRENT_USER, MYF(0));
-      result= -1;
-    }
+      result= ER_INVALID_CURRENT_USER;
     else if (access)
       *access= acl_user->access;
 
@@ -2649,9 +2680,9 @@ static int check_user_can_set_role(const char *user, const char *host,
   role= find_acl_role(rolename);
 
   /* According to SQL standard, the same error message must be presented */
-  if (role == NULL) {
-    my_error(ER_INVALID_ROLE, MYF(0), rolename);
-    result= -1;
+  if (role == NULL)
+  {
+    result= ER_INVALID_ROLE;
     goto end;
   }
 
@@ -2672,7 +2703,6 @@ static int check_user_can_set_role(const char *user, const char *host,
   /* According to SQL standard, the same error message must be presented */
   if (!is_granted)
   {
-    my_error(ER_INVALID_ROLE, MYF(0), rolename);
     result= 1;
     goto end;
   }
@@ -2681,17 +2711,66 @@ static int check_user_can_set_role(const char *user, const char *host,
   {
     *access = acl_user->access | role->access;
   }
+
 end:
   mysql_mutex_unlock(&acl_cache->lock);
-  return result;
 
+  /* We present different error messages depending if the user has sufficient
+     privileges to know if the INVALID_ROLE exists. */
+  switch (result)
+  {
+    case ER_INVALID_CURRENT_USER:
+      my_error(ER_INVALID_CURRENT_USER, MYF(0), rolename);
+      break;
+    case ER_INVALID_ROLE:
+      /* Role doesn't exist at all */
+      my_error(ER_INVALID_ROLE, MYF(0), rolename);
+      break;
+    case 1:
+      StringBuffer<1024> c_usr;
+      LEX_CSTRING role_lex;
+      /* First, check if current user can see mysql database. */
+      bool read_access= !check_access(thd, SELECT_ACL, "mysql", NULL, NULL, 1, 1);
+
+      role_lex.str= rolename;
+      role_lex.length= strlen(rolename);
+      mysql_mutex_lock(&acl_cache->lock);
+      ACL_USER *cur_user= find_user_or_anon(thd->security_ctx->priv_host,
+                                            thd->security_ctx->priv_user,
+                                            thd->security_ctx->ip);
+
+      /* If the current user does not have select priv to mysql database,
+         see if the current user can discover the role if it was granted to him.
+      */
+      if (cur_user && (read_access ||
+                       traverse_role_graph_down(cur_user, &role_lex,
+                                                check_role_is_granted_callback,
+                                                NULL) == -1))
+      {
+        /* Role is not granted but current user can see the role */
+        c_usr.append(user, strlen(user));
+        c_usr.append('@');
+        c_usr.append(host, strlen(host));
+        my_printf_error(ER_INVALID_ROLE, "User %`s has not been granted role %`s",
+                        MYF(0), c_usr.c_ptr(), rolename);
+      }
+      else
+      {
+        /* Role is not granted and current user cannot see the role */
+        my_error(ER_INVALID_ROLE, MYF(0), rolename);
+      }
+      mysql_mutex_unlock(&acl_cache->lock);
+      break;
+  }
+
+  return result;
 }
 
+
 int acl_check_setrole(THD *thd, char *rolename, ulonglong *access)
 {
-    /* Yes! priv_user@host. Don't ask why - that's what check_access() does. */
-  return check_user_can_set_role(thd->security_ctx->priv_user,
-        thd->security_ctx->host, thd->security_ctx->ip, rolename, access);
+  return check_user_can_set_role(thd, thd->security_ctx->priv_user,
+           thd->security_ctx->host, thd->security_ctx->ip, rolename, access);
 }
 
 
@@ -3471,9 +3550,12 @@ bool change_password(THD *thd, LEX_USER *user)
   DBUG_RETURN(result);
 }
 
-int acl_check_set_default_role(THD *thd, const char *host, const char *user)
+int acl_check_set_default_role(THD *thd, const char *host, const char *user,
+                               const char *role)
 {
-  return check_alter_user(thd, host, user);
+  DBUG_ENTER("acl_check_set_default_role");
+  DBUG_RETURN(check_alter_user(thd, host, user) ||
+              check_user_can_set_role(thd, user, host, NULL, role, NULL));
 }
 
 int acl_set_default_role(THD *thd, const char *host, const char *user,
@@ -3494,16 +3576,6 @@ int acl_set_default_role(THD *thd, const char *host, const char *user,
   DBUG_PRINT("enter",("host: '%s'  user: '%s'  rolename: '%s'",
                       safe_str(user), safe_str(host), safe_str(rolename)));
 
-  if (rolename == current_role.str) {
-    if (!thd->security_ctx->priv_role[0])
-      rolename= "NONE";
-    else
-      rolename= thd->security_ctx->priv_role;
-  }
-
-  if (check_user_can_set_role(user, host, host, rolename, NULL))
-    DBUG_RETURN(result);
-
   if (!strcasecmp(rolename, "NONE"))
     clear_role= TRUE;
 
@@ -3667,31 +3739,6 @@ bool is_acl_user(const char *host, const char *user)
   return res;
 }
 
-
-/*
-  unlike find_user_exact and find_user_wild,
-  this function finds anonymous users too, it's when a
-  user is not empty, but priv_user (acl_user->user) is empty.
-*/
-static ACL_USER *find_user_or_anon(const char *host, const char *user, const char *ip)
-{
-  ACL_USER *result= NULL;
-  mysql_mutex_assert_owner(&acl_cache->lock);
-  for (uint i=0; i < acl_users.elements; i++)
-  {
-    ACL_USER *acl_user_tmp= dynamic_element(&acl_users, i, ACL_USER*);
-    if ((!acl_user_tmp->user.str ||
-         !strcmp(user, acl_user_tmp->user.str)) &&
-         compare_hostname(&acl_user_tmp->host, host, ip))
-    {
-      result= acl_user_tmp;
-      break;
-    }
-  }
-  return result;
-}
-
-
 /*
   Find first entry that matches the specified user@host pair
 */
@@ -3997,7 +4044,7 @@ static bool test_if_create_new_users(THD *thd)
     if (!(db_access & INSERT_ACL))
     {
       if (check_grant(thd, INSERT_ACL, &tl, FALSE, UINT_MAX, TRUE))
-	create_new_users=0;
+        create_new_users=0;
     }
   }
   return create_new_users;
@@ -9244,17 +9291,6 @@ void get_mqh(const char *user, const char *host, USER_CONN *uc)
   mysql_mutex_unlock(&acl_cache->lock);
 }
 
-static int check_role_is_granted_callback(ACL_USER_BASE *grantee, void *data)
-{
-  LEX_CSTRING *rolename= static_cast<LEX_CSTRING *>(data);
-  if (rolename->length == grantee->user.length &&
-      !strcmp(rolename->str, grantee->user.str))
-    return -1; // End search, we've found our role.
-
-  /* Keep looking, we haven't found our role yet. */
-  return 0;
-}
-
 /*
   Modify a privilege table.
 
@@ -11094,7 +11130,7 @@ acl_check_proxy_grant_access(THD *thd, const char *host, const char *user,
     Security context in THD contains two pairs of (user,host):
     1. (user,host) pair referring to inbound connection.
     2. (priv_user,priv_host) pair obtained from mysql.user table after doing
-        authnetication of incoming connection.
+        authentication of incoming connection.
     Privileges should be checked wrt (priv_user, priv_host) tuple, because
     (user,host) pair obtained from inbound connection may have different
     values than what is actually stored in mysql.user table and while granting
@@ -11511,7 +11547,7 @@ int fill_schema_user_privileges(THD *thd, TABLE_LIST *tables, COND *cond)
       ulong j,test_access= want_access & ~GRANT_ACL;
       for (priv_id=0, j = SELECT_ACL;j <= GLOBAL_ACLS; priv_id++,j <<= 1)
       {
-	if (test_access & j)
+        if (test_access & j)
         {
           if (update_schema_privilege(thd, table, buff, 0, 0, 0, 0,
                                       command_array[priv_id],

sql/sql_acl.h

@@ -409,7 +409,7 @@ bool acl_check_proxy_grant_access (THD *thd, const char *host, const char *user,
                                    bool with_grant);
 int acl_setrole(THD *thd, char *rolename, ulonglong access);
 int acl_check_setrole(THD *thd, char *rolename, ulonglong *access);
-int acl_check_set_default_role(THD *thd, const char *host, const char *user);
+int acl_check_set_default_role(THD *thd, const char *host, const char *user, const char *role);
 int acl_set_default_role(THD *thd, const char *host, const char *user,
                          const char *rolename);
 

sql/sql_statistics.h

@@ -280,7 +280,6 @@ class Table_statistics
   Column_statistics *column_stats;  /* Array of statistical data for columns */
   Index_statistics *index_stats;    /* Array of statistical data for indexes */
   ulong *idx_avg_frequency;   /* Array of records per key for index prefixes */
-  ulong total_hist_size;            /* Total size of all histograms */
   uchar *histograms;                /* Sequence of histograms       */                    
 };
 

sql/table.cc

@@ -440,10 +440,6 @@ void TABLE_SHARE::destroy()
 
   delete_stat_values_for_table_share(this);
   free_root(&stats_cb.mem_root, MYF(0));
-  stats_cb.stats_can_be_read= FALSE;
-  stats_cb.stats_is_read= FALSE;
-  stats_cb.histograms_can_be_read= FALSE;
-  stats_cb.histograms_are_read= FALSE;
 
   /* The mutexes are initialized only for shares that are part of the TDC */
   if (tmp_table == NO_TMP_TABLE)

sql/table.h

@@ -567,15 +567,94 @@ enum open_frm_error {
   from persistent statistical tables
 */
 
-struct TABLE_STATISTICS_CB
+class TABLE_STATISTICS_CB
 {
+  class Statistics_state
+  {
+    enum state_codes
+    {
+      EMPTY,   /** data is not loaded */
+      LOADING, /** data is being loaded in some connection */
+      READY    /** data is loaded and available for use */
+    };
+    int32 state;
+
+  public:
+    /** No state copy */
+    Statistics_state &operator=(const Statistics_state &) { return *this; }
+
+    /** Checks if data loading have been completed */
+    bool is_ready() const
+    {
+      return my_atomic_load32_explicit(const_cast<int32*>(&state),
+                                       MY_MEMORY_ORDER_ACQUIRE) == READY;
+    }
+
+    /**
+      Sets mutual exclusion for data loading
+
+      If stats are in LOADING state, waits until state change.
+
+      @return
+        @retval true atomic EMPTY -> LOADING transfer completed, ok to load
+        @retval false stats are in READY state, no need to load
+    */
+    bool start_load()
+    {
+      for (;;)
+      {
+        int32 expected= EMPTY;
+        if (my_atomic_cas32_weak_explicit(&state, &expected, LOADING,
+                                          MY_MEMORY_ORDER_RELAXED,
+                                          MY_MEMORY_ORDER_RELAXED))
+          return true;
+        if (expected == READY)
+          return false;
+        (void) LF_BACKOFF;
+      }
+    }
+
+    /** Marks data available for subsequent use */
+    void end_load()
+    {
+      DBUG_ASSERT(my_atomic_load32_explicit(&state, MY_MEMORY_ORDER_RELAXED) ==
+                  LOADING);
+      my_atomic_store32_explicit(&state, READY, MY_MEMORY_ORDER_RELEASE);
+    }
+
+    /** Restores empty state on error (e.g. OOM) */
+    void abort_load()
+    {
+      DBUG_ASSERT(my_atomic_load32_explicit(&state, MY_MEMORY_ORDER_RELAXED) ==
+                  LOADING);
+      my_atomic_store32_explicit(&state, EMPTY, MY_MEMORY_ORDER_RELAXED);
+    }
+  };
+
+  class Statistics_state stats_state;
+  class Statistics_state hist_state;
+
+public:
   MEM_ROOT  mem_root; /* MEM_ROOT to allocate statistical data for the table */
   Table_statistics *table_stats; /* Structure to access the statistical data */
-  bool stats_can_be_read;        /* Memory for statistical data is allocated */
-  bool stats_is_read;            /* Statistical data for table has been read
-                                    from statistical tables */
-  bool histograms_can_be_read;
-  bool histograms_are_read;   
+  ulong total_hist_size;         /* Total size of all histograms */
+
+  bool histograms_are_ready() const
+  {
+    return !total_hist_size || hist_state.is_ready();
+  }
+
+  bool start_histograms_load()
+  {
+    return total_hist_size && hist_state.start_load();
+  }
+
+  void end_histograms_load() { hist_state.end_load(); }
+  void abort_histograms_load() { hist_state.abort_load(); }
+  bool stats_are_ready() const { return stats_state.is_ready(); }
+  bool start_stats_load() { return stats_state.start_load(); }
+  void end_stats_load() { stats_state.end_load(); }
+  void abort_stats_load() { stats_state.abort_load(); }
 };
 
 

storage/mroonga/mrn_table.cpp

@@ -932,7 +932,7 @@ MRN_SHARE *mrn_get_share(const char *table_name, TABLE *table, int *error)
         share->wrap_key_info = NULL;
         share->wrap_primary_key = MAX_KEY;
       }
-      memcpy(wrap_table_share, table->s, sizeof(*wrap_table_share));
+      *wrap_table_share= *table->s;
       mrn_init_sql_alloc(current_thd, &(wrap_table_share->mem_root));
       wrap_table_share->keys = share->wrap_keys;
       wrap_table_share->key_info = share->wrap_key_info;