Merge bk-internal.mysql.com:/home/bk/mysql-5.0-runtime

into  bodhi.local:/opt/local/work/mysql-5.0-26750

sql/log_event.cc

@@ -3114,8 +3114,8 @@ int Load_log_event::exec_event(NET* net, struct st_relay_log_info* rli,
 
       ex.skip_lines = skip_lines;
       List<Item> field_list;
-      thd->main_lex.select_lex.context.resolve_in_table_list_only(&tables);
-      set_fields(tables.db, field_list, &thd->main_lex.select_lex.context);
+      thd->lex->select_lex.context.resolve_in_table_list_only(&tables);
+      set_fields(tables.db, field_list, &thd->lex->select_lex.context);
       thd->variables.pseudo_thread_id= thread_id;
       if (net)
       {

sql/mysqld.cc

@@ -1598,18 +1598,6 @@ static void network_init(void)
 
 #endif /*!EMBEDDED_LIBRARY*/
 
-void MYSQLerror(const char *s)
-{
-  THD *thd=current_thd;
-  char *yytext= (char*) thd->lex->tok_start;
-  /* "parse error" changed into "syntax error" between bison 1.75 and 1.875 */
-  if (strcmp(s,"parse error") == 0 || strcmp(s,"syntax error") == 0)
-    s=ER(ER_SYNTAX_ERROR);
-  my_printf_error(ER_PARSE_ERROR,  ER(ER_PARSE_ERROR), MYF(0), s,
-                  (yytext ? (char*) yytext : ""),
-                  thd->lex->yylineno);
-}
-
 
 #ifndef EMBEDDED_LIBRARY
 /*

sql/sql_class.cc

@@ -166,14 +166,10 @@ Open_tables_state::Open_tables_state(ulong version_arg)
 }
 
 
-/*
-  Pass nominal parameters to Statement constructor only to ensure that
-  the destructor works OK in case of error. The main_mem_root will be
-  re-initialized in init().
-*/
 
 THD::THD()
-  :Statement(CONVENTIONAL_EXECUTION, 0, ALLOC_ROOT_MIN_BLOCK_SIZE, 0),
+   :Statement(&main_lex, &main_mem_root, CONVENTIONAL_EXECUTION,
+              /* statement id */ 0),
    Open_tables_state(refresh_version),
    lock_id(&main_lock_id),
    user_time(0), in_sub_stmt(0), global_read_lock(0), is_fatal_error(0),
@@ -184,6 +180,12 @@ THD::THD()
 {
   ulong tmp;
 
+  /*
+    Pass nominal parameters to init_alloc_root only to ensure that
+    the destructor works OK in case of an error. The main_mem_root
+    will be re-initialized in init_for_queries().
+  */
+  init_sql_alloc(&main_mem_root, ALLOC_ROOT_MIN_BLOCK_SIZE, 0);
   stmt_arena= this;
   thread_stack= 0;
   db= 0;
@@ -475,6 +477,7 @@ THD::~THD()
 #ifndef DBUG_OFF
   dbug_sentry= THD_SENTRY_GONE;
 #endif  
+  free_root(&main_mem_root, MYF(0));
   DBUG_VOID_RETURN;
 }
 
@@ -1613,18 +1616,17 @@ void Query_arena::cleanup_stmt()
   Statement functions 
 */
 
-Statement::Statement(enum enum_state state_arg, ulong id_arg,
-                     ulong alloc_block_size, ulong prealloc_size)
-  :Query_arena(&main_mem_root, state_arg),
+Statement::Statement(LEX *lex_arg, MEM_ROOT *mem_root_arg,
+                     enum enum_state state_arg, ulong id_arg)
+  :Query_arena(mem_root_arg, state_arg),
   id(id_arg),
   set_query_id(1),
-  lex(&main_lex),
+  lex(lex_arg),
   query(0),
   query_length(0),
   cursor(0)
 {
   name.str= NULL;
-  init_sql_alloc(&main_mem_root, alloc_block_size, prealloc_size);
 }
 
 
@@ -1666,7 +1668,7 @@ void Statement::restore_backup_statement(Statement *stmt, Statement *backup)
 
 void THD::end_statement()
 {
-  /* Cleanup SQL processing state to resuse this statement in next query. */
+  /* Cleanup SQL processing state to reuse this statement in next query. */
   lex_end(lex);
   delete lex->result;
   lex->result= 0;
@@ -1707,12 +1709,6 @@ void THD::restore_active_arena(Query_arena *set, Query_arena *backup)
 
 Statement::~Statement()
 {
-  /*
-    We must free `main_mem_root', not `mem_root' (pointer), to work
-    correctly if this statement is used as a backup statement,
-    for which `mem_root' may point to some other statement.
-  */
-  free_root(&main_mem_root, MYF(0));
 }
 
 C_MODE_START

sql/sql_class.h

@@ -753,8 +753,10 @@ public:
 
 class Server_side_cursor;
 
-/*
-  State of a single command executed against this connection.
+/**
+  @class Statement
+  @brief State of a single command executed against this connection.
+
   One connection can contain a lot of simultaneously running statements,
   some of which could be:
    - prepared, that is, contain placeholders,
@@ -772,10 +774,6 @@ class Statement: public ilink, public Query_arena
   Statement(const Statement &rhs);              /* not implemented: */
   Statement &operator=(const Statement &rhs);   /* non-copyable */
 public:
-  /* FIXME: these must be protected */
-  MEM_ROOT main_mem_root;
-  LEX     main_lex;
-
   /*
     Uniquely identifies each statement object in thread scope; change during
     statement lifetime. FIXME: must be const
@@ -819,10 +817,10 @@ public:
 public:
 
   /* This constructor is called for backup statements */
-  Statement() { clear_alloc_root(&main_mem_root); }
+  Statement() {}
 
-  Statement(enum enum_state state_arg, ulong id_arg,
-            ulong alloc_block_size, ulong prealloc_size);
+  Statement(LEX *lex_arg, MEM_ROOT *mem_root_arg,
+            enum enum_state state_arg, ulong id_arg);
   virtual ~Statement();
 
   /* Assign execution context (note: not all members) of given stmt to self */
@@ -834,7 +832,7 @@ public:
 };
 
 
-/*
+/**
   Container for all statements created/used in a connection.
   Statements in Statement_map have unique Statement::id (guaranteed by id
   assignment in Statement::Statement)
@@ -914,6 +912,10 @@ bool xid_cache_insert(XID *xid, enum xa_states xa_state);
 bool xid_cache_insert(XID_STATE *xid_state);
 void xid_cache_delete(XID_STATE *xid_state);
 
+/**
+  @class Security_context
+  @brief A set of THD members describing the current authenticated user.
+*/
 
 class Security_context {
 public:
@@ -943,7 +945,7 @@ public:
 };
 
 
-/*
+/**
   A registry for item tree transformations performed during
   query optimization. We register only those changes which require
   a rollback to re-execute a prepared statement or stored procedure
@@ -954,7 +956,7 @@ struct Item_change_record;
 typedef I_List<Item_change_record> Item_change_list;
 
 
-/*
+/**
   Type of prelocked mode.
   See comment for THD::prelocked_mode for complete description.
 */
@@ -963,7 +965,7 @@ enum prelocked_mode_type {NON_PRELOCKED= 0, PRELOCKED= 1,
                           PRELOCKED_UNDER_LOCK_TABLES= 2};
 
 
-/*
+/**
   Class that holds information about tables which were opened and locked
   by the thread. It is also used to save/restore this information in
   push_open_tables_state()/pop_open_tables_state().
@@ -1048,14 +1050,17 @@ public:
   }
 };
 
-
-/* class to save context when executing a function or trigger */
+/**
+  @class Sub_statement_state
+  @brief Used to save context when executing a function or trigger
+*/
 
 /* Defines used for Sub_statement_state::in_sub_stmt */
 
 #define SUB_STMT_TRIGGER 1
 #define SUB_STMT_FUNCTION 2
 
+
 class Sub_statement_state
 {
 public:
@@ -1114,7 +1119,8 @@ public:
 };
 
 
-/*
+/**
+  @class THD
   For each client connection we create a separate thread with THD serving as
   a thread/connection descriptor
 */
@@ -1726,6 +1732,22 @@ public:
 private:
   /** The current internal error handler for this thread, or NULL. */
   Internal_error_handler *m_internal_handler;
+  /**
+    The lex to hold the parsed tree of conventional (non-prepared) queries.
+    Whereas for prepared and stored procedure statements we use an own lex
+    instance for each new query, for conventional statements we reuse
+    the same lex. (@see mysql_parse for details).
+  */
+  LEX main_lex;
+  /**
+    This memory root is used for two purposes:
+    - for conventional queries, to allocate structures stored in main_lex
+    during parsing, and allocate runtime data (execution plan, etc.)
+    during execution.
+    - for prepared queries, only to allocate runtime data. The parsed
+    tree itself is reused between executions and thus is stored elsewhere.
+  */
+  MEM_ROOT main_mem_root;
 };
 
 

sql/sql_lex.cc

@@ -1648,6 +1648,36 @@ void st_select_lex::print_limit(THD *thd, String *str)
   }
 }
 
+/**
+  @brief Restore the LEX and THD in case of a parse error.
+
+  This is a clean up call that is invoked by the Bison generated
+  parser before returning an error from MYSQLparse. If your
+  semantic actions manipulate with the global thread state (which
+  is a very bad practice and should not normally be employed) and
+  need a clean-up in case of error, and you can not use %destructor
+  rule in the grammar file itself, this function should be used
+  to implement the clean up.
+*/
+
+void st_lex::cleanup_lex_after_parse_error(THD *thd)
+{
+  /*
+    Delete sphead for the side effect of restoring of the original
+    LEX state, thd->lex, thd->mem_root and thd->free_list if they
+    were replaced when parsing stored procedure statements.  We
+    will never use sphead object after a parse error, so it's okay
+    to delete it only for the sake of the side effect.
+    TODO: make this functionality explicit in sp_head class.
+    Sic: we must nullify the member of the main lex, not the
+    current one that will be thrown away
+  */
+  if (thd->lex->sphead);
+  {
+    delete thd->lex->sphead;
+    thd->lex->sphead= NULL;
+  }
+}
 
 /*
   Initialize (or reset) Query_tables_list object.

sql/sql_lex.h

@@ -1182,6 +1182,10 @@ typedef struct st_lex : public Query_tables_list
   {
     return context_stack.head();
   }
+  /*
+    Restore the LEX and THD in case of a parse error.
+  */
+  static void cleanup_lex_after_parse_error(THD *thd);
 
   void reset_n_backup_query_tables_list(Query_tables_list *backup);
   void restore_backup_query_tables_list(Query_tables_list *backup);

sql/sql_parse.cc

@@ -4506,9 +4506,6 @@ end_with_restore_list:
       clean up the environment.
     */
 create_sp_error:
-    lex->unit.cleanup();
-    delete lex->sphead;
-    lex->sphead= 0;
     if (sp_result != SP_OK )
       goto error;
     send_ok(thd);
@@ -4879,9 +4876,6 @@ create_sp_error:
     /* Conditionally writes to binlog. */
     res= mysql_create_or_drop_trigger(thd, all_tables, 1);
 
-    /* We don't care about trigger body after this point */
-    delete lex->sphead;
-    lex->sphead= 0;
     break;
   }
   case SQLCOM_DROP_TRIGGER:
@@ -5904,15 +5898,7 @@ void mysql_parse(THD *thd, char *inBuf, uint length)
       else
 #endif
       {
-	if (thd->net.report_error)
-	{
-	  if (thd->lex->sphead)
-	  {
-	    delete thd->lex->sphead;
-	    thd->lex->sphead= NULL;
-	  }
-	}
-	else
+	if (! thd->net.report_error)
 	{
           /*
             Binlog logs a string starting from thd->query and having length
@@ -5932,7 +5918,6 @@ void mysql_parse(THD *thd, char *inBuf, uint length)
 	  query_cache_end_of_result(thd);
 	}
       }
-      lex->unit.cleanup();
     }
     else
     {
@@ -5940,19 +5925,14 @@ void mysql_parse(THD *thd, char *inBuf, uint length)
       DBUG_PRINT("info",("Command aborted. Fatal_error: %d",
 			 thd->is_fatal_error));
 
-      /*
-        The first thing we do after parse error is freeing sp_head to
-        ensure that we have restored original memroot.
-      */
-      if (thd->lex->sphead)
-      {
-	/* Clean up after failed stored procedure/function */
-	delete thd->lex->sphead;
-	thd->lex->sphead= NULL;
-      }
       query_cache_abort(&thd->net);
-      lex->unit.cleanup();
     }
+    if (thd->lex->sphead)
+    {
+      delete thd->lex->sphead;
+      thd->lex->sphead= 0;
+    }
+    lex->unit.cleanup();
     thd->proc_info="freeing items";
     thd->end_statement();
     thd->cleanup_after_query();

sql/sql_prepare.cc

@@ -99,9 +99,12 @@ public:
 #endif
 };
 
-/******************************************************************************
-  Prepared_statement: a statement that can contain placeholders
-******************************************************************************/
+/****************************************************************************/
+
+/**
+  @class Prepared_statement
+  @brief Prepared_statement: a statement that can contain placeholders
+*/
 
 class Prepared_statement: public Statement
 {
@@ -141,6 +144,16 @@ public:
   bool execute(String *expanded_query, bool open_cursor);
   /* Destroy this statement */
   bool deallocate();
+private:
+  /**
+    Store the parsed tree of a prepared statement here.
+  */
+  LEX main_lex;
+  /**
+    The memory root to allocate parsed tree elements (instances of Item,
+    SELECT_LEX and other classes).
+  */
+  MEM_ROOT main_mem_root;
 };
 
 
@@ -2034,6 +2047,7 @@ void mysql_sql_stmt_prepare(THD *thd)
     delete stmt;
     DBUG_VOID_RETURN;
   }
+
   if (thd->stmt_map.insert(thd, stmt))
   {
     /* The statement is deleted and an error is set if insert fails */
@@ -2629,17 +2643,18 @@ Select_fetch_protocol_prep::send_data(List<Item> &fields)
 ****************************************************************************/
 
 Prepared_statement::Prepared_statement(THD *thd_arg, Protocol *protocol_arg)
-  :Statement(INITIALIZED, ++thd_arg->statement_id_counter,
-             thd_arg->variables.query_alloc_block_size,
-             thd_arg->variables.query_prealloc_size),
+  :Statement(&main_lex, &main_mem_root,
+             INITIALIZED, ++thd_arg->statement_id_counter),
   thd(thd_arg),
   result(thd_arg),
   protocol(protocol_arg),
   param_array(0),
   param_count(0),
   last_errno(0),
-   flags((uint) IS_IN_USE)
+  flags((uint) IS_IN_USE)
 {
+  init_alloc_root(&main_mem_root, thd_arg->variables.query_alloc_block_size,
+                  thd_arg->variables.query_prealloc_size);
   *last_error= '\0';
 }
 
@@ -2688,6 +2703,7 @@ Prepared_statement::~Prepared_statement()
   */
   free_items();
   delete lex->result;
+  free_root(&main_mem_root, MYF(0));
   DBUG_VOID_RETURN;
 }
 
@@ -2703,6 +2719,7 @@ void Prepared_statement::cleanup_stmt()
   DBUG_ENTER("Prepared_statement::cleanup_stmt");
   DBUG_PRINT("enter",("stmt: %p", this));
 
+  DBUG_ASSERT(lex->sphead == 0);
   /* The order is important */
   lex->unit.cleanup();
   cleanup_items(free_list);
@@ -2789,15 +2806,6 @@ bool Prepared_statement::prepare(const char *packet, uint packet_len)
   error= MYSQLparse((void *)thd) || thd->is_fatal_error ||
       thd->net.report_error || init_param_array(this);
 
-  /*
-    The first thing we do after parse error is freeing sp_head to
-    ensure that we have restored original memroot.
-  */
-  if (error && lex->sphead)
-  {
-    delete lex->sphead;
-    lex->sphead= NULL;
-  }
   /*
     While doing context analysis of the query (in check_prepared_statement)
     we allocate a lot of additional memory: for open tables, JOINs, derived
@@ -2823,12 +2831,18 @@ bool Prepared_statement::prepare(const char *packet, uint packet_len)
   if (error == 0)
     error= check_prepared_statement(this, name.str != 0);
 
-  /* Free sp_head if check_prepared_statement() failed. */
-  if (error && lex->sphead)
+  /*
+    Currently CREATE PROCEDURE/TRIGGER/EVENT are prohibited in prepared
+    statements: ensure we have no memory leak here if by someone tries
+    to PREPARE stmt FROM "CREATE PROCEDURE ..."
+  */
+  DBUG_ASSERT(lex->sphead == NULL || error != 0);
+  if (lex->sphead)
   {
     delete lex->sphead;
     lex->sphead= NULL;
   }
+
   lex_end(lex);
   cleanup_stmt();
   thd->restore_backup_statement(this, &stmt_backup);

sql/sql_trigger.cc

@@ -983,11 +983,8 @@ bool Table_triggers_list::check_n_load(THD *thd, const char *db,
 	thd->spcont= 0;
         if (MYSQLparse((void *)thd) || thd->is_fatal_error)
         {
-          /*
-            Free lex associated resources.
-            QQ: Do we really need all this stuff here ?
-          */
-          delete lex.sphead;
+          /* Currently sphead is always deleted in case of a parse error */
+          DBUG_ASSERT(lex.sphead == 0);
           goto err_with_lex_cleanup;
         }