sp_head now has its own mem_root (WL#961).

Also fixed some difficult memory leaks that became apparent
in this task.


sql/sp.cc:
  sp_head now has its own mem_root.
sql/sp_head.cc:
  sp_head now has its own mem_root.
  Also fixed some difficult memory leaks.
sql/sp_head.h:
  sp_head now has its own mem_root.
sql/sql_lex.h:
  Fixed some memory leaks in sp_head. Need to keep track on used lex:es.
sql/sql_parse.cc:
  sp_head now has its own mem_root.
  Fixed SP memory leaks.
sql/sql_prepare.cc:
  Fixed SP memory leaks.
sql/sql_yacc.yy:
  sp_head now has its own mem_root.

sql/sp.cc

@@ -151,7 +151,8 @@ db_find_routine(THD *thd, int type, char *name, uint namelen, sp_head **sphp)
       {
 	if (oldlex != thd->lex)
 	  thd->lex->sphead->restore_lex(thd);
-	thd->lex->sphead->destroy();
+	delete thd->lex->sphead;
+	thd->lex= NULL;
       }
       ret= SP_PARSE_ERROR;
     }
@@ -444,7 +445,7 @@ sp_clear_function_cache(THD *thd)
   sp_head *sp;
 
   while ((sp= li++))
-    sp->destroy();
+    delete sp;
   thd->spfuns.empty();
 }
 

sql/sp_head.cc

@@ -81,7 +81,7 @@ eval_func_item(THD *thd, Item *it, enum enum_field_types type)
 	String *s= it->val_str(&tmp);
 
 	DBUG_PRINT("info",("default result: %*s",s->length(),s->c_ptr_quick()));
-	it= new Item_string(sql_strmake(s->c_ptr_quick(), s->length()),
+	it= new Item_string(thd->strmake(s->c_ptr_quick(), s->length()),
 			    s->length(), it->charset());
 	break;
       }
@@ -91,6 +91,34 @@ eval_func_item(THD *thd, Item *it, enum enum_field_types type)
   DBUG_RETURN(it);
 }
 
+void *
+sp_head::operator new(size_t size)
+{
+  DBUG_ENTER("sp_head::operator new");
+  MEM_ROOT own_root;
+  sp_head *sp;
+
+  bzero((char *)&own_root, sizeof(own_root));
+  init_alloc_root(&own_root, MEM_ROOT_BLOCK_SIZE, MEM_ROOT_PREALLOC);
+  sp= (sp_head *)alloc_root(&own_root, size);
+  sp->m_mem_root= own_root;
+  
+  DBUG_RETURN(sp);
+}
+
+void 
+sp_head::operator delete(void *ptr, size_t size)
+{
+  DBUG_ENTER("sp_head::operator delete");
+  MEM_ROOT own_root;
+  sp_head *sp= (sp_head *)ptr;
+
+  memcpy(&own_root, (const void *)&sp->m_mem_root, sizeof(MEM_ROOT));
+  free_root(&own_root, MYF(0));
+
+  DBUG_VOID_RETURN;
+}
+
 sp_head::sp_head(LEX_STRING *name, LEX *lex, LEX_STRING *comment, char suid)
   : Sql_alloc(), m_simple_case(FALSE), m_multi_query(FALSE)
 {
@@ -102,6 +130,7 @@ sp_head::sp_head(LEX_STRING *name, LEX *lex, LEX_STRING *comment, char suid)
   m_name.str= name->str;
   m_defstr.length= lex->end_of_query - lex->buf;
   m_defstr.str= lex->thd->strmake(dstr, m_defstr.length);
+  m_free_list= NULL;
 
   m_comment.length= 0;
   m_comment.str= 0;
@@ -115,6 +144,7 @@ sp_head::sp_head(LEX_STRING *name, LEX *lex, LEX_STRING *comment, char suid)
   m_pcont= lex->spcont;
   my_init_dynamic_array(&m_instr, sizeof(sp_instr *), 16, 8);
   m_backpatch.empty();
+  m_lex.empty();
   DBUG_VOID_RETURN;
 }
 
@@ -142,13 +172,31 @@ sp_head::create(THD *thd)
   DBUG_RETURN(ret);
 }
 
+sp_head::~sp_head()
+{
+  destroy();
+  if (m_thd)
+    restore_thd_mem_root(m_thd);
+}
+
 void
 sp_head::destroy()
 {
   DBUG_ENTER("sp_head::destroy");
   DBUG_PRINT("info", ("name: %s", m_name.str));
+  sp_instr *i;
+  LEX *lex;
+
+  for (uint ip = 0 ; (i = get_instr(ip)) ; ip++)
+    delete i;
   delete_dynamic(&m_instr);
   m_pcont->destroy();
+  free_items(m_free_list);
+  while ((lex= (LEX *)m_lex.pop()))
+  {
+    if (lex != &m_thd->main_lex) // We got interrupted and have lex'es left
+      delete lex;
+  }
   DBUG_VOID_RETURN;
 }
 
@@ -367,20 +415,22 @@ sp_head::reset_lex(THD *thd)
 {
   DBUG_ENTER("sp_head::reset_lex");
   LEX *sublex;
+  LEX *oldlex= thd->lex;
 
-  m_lex= thd->lex;
+  (void)m_lex.push_front(oldlex);
   thd->lex= sublex= new st_lex;
-  sublex->yylineno= m_lex->yylineno;
+  sublex->yylineno= oldlex->yylineno;
   /* Reset most stuff. The length arguments doesn't matter here. */
-  lex_start(thd, m_lex->buf, m_lex->end_of_query - m_lex->ptr);
+  lex_start(thd, oldlex->buf, oldlex->end_of_query - oldlex->ptr);
   /* We must reset ptr and end_of_query again */
-  sublex->ptr= m_lex->ptr;
-  sublex->end_of_query= m_lex->end_of_query;
-  sublex->tok_start= m_lex->tok_start;
+  sublex->ptr= oldlex->ptr;
+  sublex->end_of_query= oldlex->end_of_query;
+  sublex->tok_start= oldlex->tok_start;
   /* And keep the SP stuff too */
-  sublex->sphead= m_lex->sphead;
-  sublex->spcont= m_lex->spcont;
+  sublex->sphead= oldlex->sphead;
+  sublex->spcont= oldlex->spcont;
   mysql_init_query(thd, true);	// Only init lex
+  sublex->sp_lex_in_use= FALSE;
   DBUG_VOID_RETURN;
 }
 
@@ -390,14 +440,18 @@ sp_head::restore_lex(THD *thd)
 {
   DBUG_ENTER("sp_head::restore_lex");
   LEX *sublex= thd->lex;
+  LEX *oldlex= (LEX *)m_lex.pop();
+
+  if (! oldlex)
+    return;			// Nothing to restore
 
   // Update some state in the old one first
-  m_lex->ptr= sublex->ptr;
-  m_lex->next_state= sublex->next_state;
+  oldlex->ptr= sublex->ptr;
+  oldlex->next_state= sublex->next_state;
 
   // Collect some data from the sub statement lex.
-  sp_merge_funs(m_lex, sublex);
-#if 0
+  sp_merge_funs(oldlex, sublex);
+#ifdef NOT_USED_NOW
   // QQ We're not using this at the moment.
   if (sublex.sql_command == SQLCOM_CALL)
   {
@@ -438,8 +492,9 @@ sp_head::restore_lex(THD *thd)
     }
   }
 #endif
-
-  thd->lex= m_lex;
+  if (! sublex->sp_lex_in_use)
+    delete sublex;
+  thd->lex= oldlex;
   DBUG_VOID_RETURN;
 }
 
@@ -478,6 +533,12 @@ sp_head::backpatch(sp_label_t *lab)
 //
 // sp_instr_stmt
 //
+sp_instr_stmt::~sp_instr_stmt()
+{
+  if (m_lex)
+    delete m_lex;
+}
+
 int
 sp_instr_stmt::execute(THD *thd, uint *nextp)
 {

sql/sp_head.h

@@ -54,11 +54,19 @@ class sp_head : public Sql_alloc
   List<char *> m_tables;	// Used tables.
 #endif
 
+  static void *
+  operator new(size_t size);
+
+  static void 
+  operator delete(void *ptr, size_t size);
+
   sp_head(LEX_STRING *name, LEX *lex, LEX_STRING *comment, char suid);
 
   int
   create(THD *thd);
   
+  virtual ~sp_head();
+
   // Free memory
   void
   destroy();
@@ -87,6 +95,7 @@ class sp_head : public Sql_alloc
 
   // Restores lex in 'thd' from our copy, but keeps some status from the
   // one in 'thd', like ptr, tables, fields, etc.
+  // If 'delete_lex' is true, we delete the current lex.
   void
   restore_lex(THD *thd);
 
@@ -124,8 +133,31 @@ class sp_head : public Sql_alloc
     m_suid= suid;
   }
 
+  inline void reset_thd_mem_root(THD *thd)
+  {
+    m_thd_root= thd->mem_root;
+    thd->mem_root= m_mem_root;
+    m_free_list= thd->free_list; // Keep the old list
+    thd->free_list= NULL;	// Start a new one
+    m_thd= thd;
+  }
+
+  inline void restore_thd_mem_root(THD *thd)
+  {
+    Item *flist= m_free_list;	// The old list
+    m_free_list= thd->free_list; // Get the new one
+    thd->free_list= flist;	// Restore the old one
+    m_mem_root= thd->mem_root;
+    thd->mem_root= m_thd_root;
+    m_thd= NULL;
+  }
+
 private:
 
+  MEM_ROOT m_mem_root;		// My own mem_root
+  MEM_ROOT m_thd_root;		// Temp. store for thd's mem_root
+  Item *m_free_list;		// Where the items go
+  THD *m_thd;			// Set if we have reset mem_root
   LEX_STRING m_name;
   LEX_STRING m_defstr;
   LEX_STRING m_comment;
@@ -136,7 +168,7 @@ class sp_head : public Sql_alloc
   bool m_suid;
 
   sp_pcontext *m_pcont;		// Parse context
-  LEX *m_lex;			// Temp. store for the other lex
+  List<LEX> m_lex;		// Temp. store for the other lex
   DYNAMIC_ARRAY m_instr;	// The "instructions"
   typedef struct
   {
@@ -211,11 +243,10 @@ class sp_instr_stmt : public sp_instr
 public:
 
   sp_instr_stmt(uint ip)
-    : sp_instr(ip)
+    : sp_instr(ip), m_lex(NULL)
   {}
 
-  virtual ~sp_instr_stmt()
-  {}
+  virtual ~sp_instr_stmt();
 
   virtual int execute(THD *thd, uint *nextp);
 

sql/sql_lex.h

@@ -495,6 +495,7 @@ typedef struct st_lex
   char *help_arg;
   SQL_LIST *gorder_list;
   sp_head *sphead;
+  bool sp_lex_in_use;	/* Keep track on lex usage in SPs for error handling */
   sp_pcontext *spcont;
   List<char> spfuns;		/* Called functions */
 

sql/sql_parse.cc

@@ -2829,7 +2829,7 @@ mysql_execute_command(THD *thd)
       sp_head *sph= sp_find_function(thd, &lex->udf.name);
       if (sph)
       {
-	sph->destroy();		// QQ Free memory. Remove this when caching!!!
+	delete sph;		// QQ Free memory. Remove this when caching!!!
 	net_printf(thd, ER_UDF_EXISTS, lex->udf.name.str);
 	goto error;
       }
@@ -3029,18 +3029,22 @@ mysql_execute_command(THD *thd)
 #endif
       res= lex->sphead->create(thd);
 
-      lex->sphead->destroy();	// QQ Free memory. Remove this when caching!!!
-
       switch (res)
       {
       case SP_OK:
 	send_ok(thd);
+	delete lex->sphead;	// QQ Free memory. Remove this when caching!!!
+	lex->sphead= NULL;
 	break;
       case SP_WRITE_ROW_FAILED:
 	net_printf(thd, ER_SP_ALREADY_EXISTS, SP_TYPE_STRING(lex), name);
+	delete lex->sphead;	// QQ Free memory. Remove this when caching!!!
+	lex->sphead= NULL;
 	goto error;
       default:
 	net_printf(thd, ER_SP_STORE_FAILED, SP_TYPE_STRING(lex), name);
+	delete lex->sphead;	// QQ Free memory. Remove this when caching!!!
+	lex->sphead= NULL;
 	goto error;
       }
       break;
@@ -3064,7 +3068,7 @@ mysql_execute_command(THD *thd)
 	if (tables && ((res= check_table_access(thd, SELECT_ACL, tables)) ||
 		       (res= open_and_lock_tables(thd, tables))))
 	{
-	  sp->destroy();	// QQ Free memory. Remove this when caching!!!
+	  delete sp;		// Free memory. Remove this when caching!!!
 	  break;
 	}
 	fix_tables_pointers(lex->all_selects_list);
@@ -3083,7 +3087,7 @@ mysql_execute_command(THD *thd)
 #ifndef EMBEDDED_LIBRARY
 	    thd->net.no_send_ok= nsok;
 #endif
-	    sp->destroy();	// QQ Free memory. Remove this when caching!!!
+	    delete sp;		// QQ Free memory. Remove this when caching!!!
 	    goto error;
 	  }
 	  smrx= thd->server_status & SERVER_MORE_RESULTS_EXISTS;
@@ -3101,7 +3105,7 @@ mysql_execute_command(THD *thd)
 	    thd->server_status &= ~SERVER_MORE_RESULTS_EXISTS;
 	}
 
-	sp->destroy();		// QQ Free memory. Remove this when caching!!!
+	delete sp;		// QQ Free memory. Remove this when caching!!!
 
 	if (res == 0)
 	  send_ok(thd);
@@ -3128,7 +3132,7 @@ mysql_execute_command(THD *thd)
       {
 	/* QQ This is an no-op right now, since we haven't
 	      put the characteristics in yet. */
-	sp->destroy();		// QQ Free memory. Remove this when caching!!!
+	delete sp;		// QQ Free memory. Remove this when caching!!!
 	send_ok(thd);
       }
       break;
@@ -3588,7 +3592,12 @@ mysql_parse(THD *thd, char *inBuf, uint length)
 	{
 	  send_error(thd, 0, NullS);
 	  if (thd->lex->sphead)
-	    thd->lex->sphead->destroy();
+	  {
+	    if (lex != thd->lex)
+	      thd->lex->sphead->restore_lex(thd);
+	    delete thd->lex->sphead;
+	    thd->lex->sphead= NULL;
+	  }
 	}
 	else
 	{
@@ -3606,11 +3615,14 @@ mysql_parse(THD *thd, char *inBuf, uint length)
 #ifndef EMBEDDED_LIBRARY   /* TODO query cache in embedded library*/
       query_cache_abort(&thd->net);
       if (thd->lex->sphead)
-	thd->lex->sphead->destroy();
+      {
+	if (lex != thd->lex)
+	  thd->lex->sphead->restore_lex(thd);
+	delete thd->lex->sphead;
+	thd->lex->sphead= NULL;
+      }
 #endif
     }
-    if (thd->lex->sphead && lex != thd->lex)
-      thd->lex->sphead->restore_lex(thd);
     thd->proc_info="freeing items";
     free_items(thd->free_list);  /* Free strings used by items */
     lex_end(lex);

sql/sql_prepare.cc

@@ -762,8 +762,16 @@ static bool parse_prepare_query(PREP_STMT *stmt,
   thd->lex->param_count= 0;
   if (!yyparse((void *)thd) && !thd->is_fatal_error) 
     error= send_prepare_results(stmt);
-  if (thd->lex->sphead && lex != thd->lex)
+  else
+  {
+    if (thd->lex->sphead)
+    {
+      if (lex != thd->lex)
 	thd->lex->sphead->restore_lex(thd);
+      delete thd->lex->sphead;
+      thd->lex->sphead= NULL;
+    }
+  }
   lex_end(lex);
   DBUG_RETURN(error);
 }

sql/sql_yacc.yy

@@ -948,6 +948,7 @@ create:
 	    lex->sphead->m_old_cmq=
 	      YYTHD->client_capabilities & CLIENT_MULTI_QUERIES;
 	    YYTHD->client_capabilities &= (~CLIENT_MULTI_QUERIES);
+	    lex->sphead->reset_thd_mem_root(YYTHD);
 	  }
           '(' sp_pdparam_list ')'
 	  {
@@ -961,6 +962,7 @@ create:
 	    /* Restore flag if it was cleared above */
 	    if (lex->sphead->m_old_cmq)
 	      YYTHD->client_capabilities |= CLIENT_MULTI_QUERIES;
+	    lex->sphead->restore_thd_mem_root(YYTHD);
 	  } 
 	;
 
@@ -997,6 +999,7 @@ create_function_tail:
 	    lex->sphead->m_old_cmq=
 	      YYTHD->client_capabilities & CLIENT_MULTI_QUERIES;
 	    YYTHD->client_capabilities &= ~CLIENT_MULTI_QUERIES;
+	    lex->sphead->reset_thd_mem_root(YYTHD);
 	  }
           sp_fdparam_list ')'
 	  {
@@ -1014,6 +1017,7 @@ create_function_tail:
 	    /* Restore flag if it was cleared above */
 	    if (lex->sphead->m_old_cmq)
 	      YYTHD->client_capabilities |= CLIENT_MULTI_QUERIES;
+	    lex->sphead->restore_thd_mem_root(YYTHD);
 	  }
 	;
 
@@ -1174,7 +1178,7 @@ sp_proc_stmt:
 	    **  which get their set instructions generated separately.)
 	    */
 	    if (lex->sql_command != SQLCOM_SET_OPTION ||
-		!lex->var_list.is_empty())
+		! lex->var_list.is_empty())
 	    {
 	      /* Currently we can't handle queries inside a FUNCTION,
 	      ** because of the way table locking works.
@@ -1194,6 +1198,7 @@ sp_proc_stmt:
 
 		i->set_lex(lex);
 		lex->sphead->add_instr(i);
+		lex->sp_lex_in_use= TRUE;
 	      }
             }
 	    lex->sphead->restore_lex(YYTHD);