MDEV-8010 - Avoid sql_alloc() in Items (Patch #1)

Added mandatory thd parameter to Item (and all derivative classes) constructor.
Added thd parameter to all routines that may create items.
Also removed "current_thd" from Item::Item. This reduced number of
pthread_getspecific() calls from 290 to 177 per OLTP RO transaction.

plugin/feedback/feedback.cc

@@ -99,20 +99,20 @@ static COND* make_cond(THD *thd, TABLE_LIST *tables, LEX_STRING *filter)
   nrc.init();
   nrc.resolve_in_table_list_only(tables);
 
-  res= new Item_cond_or();
+  res= new Item_cond_or(thd);
   if (!res)
     return OOM;
 
   for (; filter->str; filter++)
   {
     Item_field  *fld= new Item_field(thd, &nrc, db, table, field);
-    Item_string *pattern= new Item_string(filter->str, filter->length, cs);
-    Item_string *escape= new Item_string("\\", 1, cs);
+    Item_string *pattern= new Item_string(thd, filter->str, filter->length, cs);
+    Item_string *escape= new Item_string(thd, "\\", 1, cs);
 
     if (!fld || !pattern || !escape)
       return OOM;
 
-    Item_func_like *like= new Item_func_like(fld, pattern, escape, 0);
+    Item_func_like *like= new Item_func_like(thd, fld, pattern, escape, 0);
 
     if (!like)
       return OOM;

plugin/handler_socket/handlersocket/database.cpp

@@ -106,10 +106,10 @@ struct tablevec_entry {
 
 struct expr_user_lock : private noncopyable {
   expr_user_lock(THD *thd, int timeout)
-    : lck_key("handlersocket_wr", 16, &my_charset_latin1),
-      lck_timeout(timeout),
-      lck_func_get_lock(&lck_key, &lck_timeout),
-      lck_func_release_lock(&lck_key)
+    : lck_key(thd, "handlersocket_wr", 16, &my_charset_latin1),
+      lck_timeout(thd, timeout),
+      lck_func_get_lock(thd, &lck_key, &lck_timeout),
+      lck_func_release_lock(thd, &lck_key)
   {
     lck_key.fix_fields(thd, 0);
     lck_timeout.fix_fields(thd, 0);

sql/events.cc

@@ -639,29 +639,30 @@ send_show_create_event(THD *thd, Event_timed *et, Protocol *protocol)
   if (et->get_create_event(thd, &show_str))
     DBUG_RETURN(TRUE);
 
-  field_list.push_back(new Item_empty_string("Event", NAME_CHAR_LEN));
+  field_list.push_back(new Item_empty_string(thd, "Event", NAME_CHAR_LEN));
 
   if (sql_mode_string_representation(thd, et->sql_mode, &sql_mode))
     DBUG_RETURN(TRUE);
 
-  field_list.push_back(new Item_empty_string("sql_mode", (uint) sql_mode.length));
+  field_list.push_back(new Item_empty_string(thd, "sql_mode",
+                                             (uint) sql_mode.length));
 
   tz_name= et->time_zone->get_name();
 
-  field_list.push_back(new Item_empty_string("time_zone",
+  field_list.push_back(new Item_empty_string(thd, "time_zone",
                                              tz_name->length()));
 
-  field_list.push_back(new Item_empty_string("Create Event",
+  field_list.push_back(new Item_empty_string(thd, "Create Event",
                                              show_str.length()));
 
   field_list.push_back(
-    new Item_empty_string("character_set_client", MY_CS_NAME_SIZE));
+    new Item_empty_string(thd, "character_set_client", MY_CS_NAME_SIZE));
 
   field_list.push_back(
-    new Item_empty_string("collation_connection", MY_CS_NAME_SIZE));
+    new Item_empty_string(thd, "collation_connection", MY_CS_NAME_SIZE));
 
   field_list.push_back(
-    new Item_empty_string("Database Collation", MY_CS_NAME_SIZE));
+    new Item_empty_string(thd, "Database Collation", MY_CS_NAME_SIZE));
 
   if (protocol->send_result_set_metadata(&field_list,
                             Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))

sql/field.cc

@@ -9987,7 +9987,7 @@ Field *make_field(TABLE_SHARE *share, uchar *ptr, uint32 field_length,
 
 /** Create a field suitable for create of table. */
 
-Create_field::Create_field(Field *old_field,Field *orig_field)
+Create_field::Create_field(THD *thd, Field *old_field, Field *orig_field)
 {
   field=      old_field;
   field_name=change=old_field->field_name;
@@ -10039,7 +10039,6 @@ Create_field::Create_field(Field *old_field,Field *orig_field)
   case MYSQL_TYPE_YEAR:
     if (length != 4)
     {
-      THD *thd= current_thd;
       char buff[sizeof("YEAR()") + MY_INT64_NUM_DECIMAL_DIGITS + 1];
       my_snprintf(buff, sizeof(buff), "YEAR(%lu)", length);
       push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
@@ -10098,7 +10097,7 @@ Create_field::Create_field(Field *old_field,Field *orig_field)
         StringBuffer<MAX_FIELD_WIDTH> tmp(charset);
         String *res= orig_field->val_str(&tmp);
         char *pos= (char*) sql_strmake(res->ptr(), res->length());
-        def= new Item_string(pos, res->length(), charset);
+        def= new Item_string(thd, pos, res->length(), charset);
       }
       orig_field->move_field_offset(-diff);	// Back to record[0]
     }

sql/field.h

@@ -3050,7 +3050,7 @@ public:
     interval_list.empty();
   }
 
-  Create_field(Field *field, Field *orig_field);
+  Create_field(THD *thd, Field *field, Field *orig_field);
   /* Used to make a clone of this object for ALTER/CREATE TABLE */
   Create_field *clone(MEM_ROOT *mem_root) const;
   void create_length_to_internal_length(void);

sql/handler.cc

@@ -1983,10 +1983,14 @@ bool mysql_xa_recover(THD *thd)
   Protocol *protocol= thd->protocol;
   DBUG_ENTER("mysql_xa_recover");
 
-  field_list.push_back(new Item_int("formatID", 0, MY_INT32_NUM_DECIMAL_DIGITS));
-  field_list.push_back(new Item_int("gtrid_length", 0, MY_INT32_NUM_DECIMAL_DIGITS));
-  field_list.push_back(new Item_int("bqual_length", 0, MY_INT32_NUM_DECIMAL_DIGITS));
-  field_list.push_back(new Item_empty_string("data",XIDDATASIZE));
+  field_list.push_back(new Item_int(thd, "formatID", 0,
+                                    MY_INT32_NUM_DECIMAL_DIGITS));
+  field_list.push_back(new Item_int(thd, "gtrid_length", 0,
+                                    MY_INT32_NUM_DECIMAL_DIGITS));
+  field_list.push_back(new Item_int(thd, "bqual_length", 0,
+                                    MY_INT32_NUM_DECIMAL_DIGITS));
+  field_list.push_back(new Item_empty_string(thd, "data",
+                                             XIDDATASIZE));
 
   if (protocol->send_result_set_metadata(&field_list,
                             Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))
@@ -5523,9 +5527,9 @@ bool ha_show_status(THD *thd, handlerton *db_type, enum ha_stat_type stat)
   Protocol *protocol= thd->protocol;
   bool result;
 
-  field_list.push_back(new Item_empty_string("Type",10));
-  field_list.push_back(new Item_empty_string("Name",FN_REFLEN));
-  field_list.push_back(new Item_empty_string("Status",10));
+  field_list.push_back(new Item_empty_string(thd, "Type", 10));
+  field_list.push_back(new Item_empty_string(thd, "Name", FN_REFLEN));
+  field_list.push_back(new Item_empty_string(thd, "Status", 10));
 
   if (protocol->send_result_set_metadata(&field_list,
                             Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF))

sql/item_func.cc

@@ -319,11 +319,11 @@ void Item_func::traverse_cond(Cond_traverser traverser,
 }
 
 
-bool Item_args::transform_args(Item_transformer transformer, uchar *arg)
+bool Item_args::transform_args(THD *thd, Item_transformer transformer, uchar *arg)
 {
   for (uint i= 0; i < arg_count; i++)
   {
-    Item *new_item= args[i]->transform(transformer, arg);
+    Item *new_item= args[i]->transform(thd, transformer, arg);
     if (!new_item)
       return true;
     /*
@@ -333,7 +333,7 @@ bool Item_args::transform_args(Item_transformer transformer, uchar *arg)
       change records at each execution.
     */
     if (args[i] != new_item)
-      current_thd->change_item_tree(&args[i], new_item);
+      thd->change_item_tree(&args[i], new_item);
   }
   return false;
 }
@@ -356,12 +356,12 @@ bool Item_args::transform_args(Item_transformer transformer, uchar *arg)
     Item returned as the result of transformation of the root node
 */
 
-Item *Item_func::transform(Item_transformer transformer, uchar *argument)
+Item *Item_func::transform(THD *thd, Item_transformer transformer, uchar *argument)
 {
-  DBUG_ASSERT(!current_thd->stmt_arena->is_stmt_prepare());
-  if (transform_args(transformer, argument))
+  DBUG_ASSERT(!thd->stmt_arena->is_stmt_prepare());
+  if (transform_args(thd, transformer, argument))
     return 0;
-  return (this->*transformer)(argument);
+  return (this->*transformer)(thd, argument);
 }
 
 
@@ -391,7 +391,7 @@ Item *Item_func::transform(Item_transformer transformer, uchar *argument)
     Item returned as the result of transformation of the root node
 */
 
-Item *Item_func::compile(Item_analyzer analyzer, uchar **arg_p,
+Item *Item_func::compile(THD *thd, Item_analyzer analyzer, uchar **arg_p,
                          Item_transformer transformer, uchar *arg_t)
 {
   if (!(this->*analyzer)(arg_p))
@@ -406,12 +406,13 @@ Item *Item_func::compile(Item_analyzer analyzer, uchar **arg_p,
         to analyze any argument of the condition formula.
       */
       uchar *arg_v= *arg_p;
-      Item *new_item= (*arg)->compile(analyzer, &arg_v, transformer, arg_t);
+      Item *new_item= (*arg)->compile(thd, analyzer, &arg_v, transformer,
+                                      arg_t);
       if (new_item && *arg != new_item)
-        current_thd->change_item_tree(arg, new_item);
+        thd->change_item_tree(arg, new_item);
     }
   }
-  return (this->*transformer)(arg_t);
+  return (this->*transformer)(thd, arg_t);
 }
 
 /**
@@ -726,7 +727,7 @@ void Item_func::signal_divide_by_null()
 Item *Item_func::get_tmp_table_item(THD *thd)
 {
   if (!with_sum_func && !const_item())
-    return new Item_field(result_field);
+    return new Item_field(thd, result_field);
   return copy_or_same(thd);
 }
 
@@ -5533,8 +5534,8 @@ get_var_with_binlog(THD *thd, enum_sql_command sql_command,
     LEX *sav_lex= thd->lex, lex_tmp;
     thd->lex= &lex_tmp;
     lex_start(thd);
-    tmp_var_list.push_back(new set_var_user(new Item_func_set_user_var(name,
-                                                                       new Item_null())));
+    tmp_var_list.push_back(new set_var_user(new Item_func_set_user_var(thd, name,
+                                                                       new Item_null(thd))));
     /* Create the variable */
     if (sql_set_variables(thd, &tmp_var_list, false))
     {
@@ -5698,7 +5699,7 @@ bool Item_func_get_user_var::eq(const Item *item, bool binary_cmp) const
 bool Item_func_get_user_var::set_value(THD *thd,
                                        sp_rcontext * /*ctx*/, Item **it)
 {
-  Item_func_set_user_var *suv= new Item_func_set_user_var(get_name(), *it);
+  Item_func_set_user_var *suv= new Item_func_set_user_var(thd, get_name(), *it);
   /*
     Item_func_set_user_var is not fixed after construction, call
     fix_fields().
@@ -5779,11 +5780,11 @@ void Item_user_var_as_out_param::print_for_load(THD *thd, String *str)
 
 
 Item_func_get_system_var::
-Item_func_get_system_var(sys_var *var_arg, enum_var_type var_type_arg,
+Item_func_get_system_var(THD *thd, sys_var *var_arg, enum_var_type var_type_arg,
                        LEX_STRING *component_arg, const char *name_arg,
-                       size_t name_len_arg)
-  :var(var_arg), var_type(var_type_arg), orig_var_type(var_type_arg),
-  component(*component_arg), cache_present(0)
+                       size_t name_len_arg):
+  Item_func(thd), var(var_arg), var_type(var_type_arg),
+  orig_var_type(var_type_arg), component(*component_arg), cache_present(0)
 {
   /* set_name() will allocate the name */
   set_name(name_arg, (uint) name_len_arg, system_charset_info);
@@ -6095,7 +6096,7 @@ void Item_func_get_system_var::cleanup()
 }
 
 
-void Item_func_match::init_search(bool no_order)
+void Item_func_match::init_search(THD *thd, bool no_order)
 {
   DBUG_ENTER("Item_func_match::init_search");
 
@@ -6113,10 +6114,10 @@ void Item_func_match::init_search(bool no_order)
   if (key == NO_SUCH_KEY)
   {
     List<Item> fields;
-    fields.push_back(new Item_string(" ", 1, cmp_collation.collation));
+    fields.push_back(new Item_string(thd, " ", 1, cmp_collation.collation));
     for (uint i= 1; i < arg_count; i++)
       fields.push_back(args[i]);
-    concat_ws= new Item_func_concat_ws(fields);
+    concat_ws= new Item_func_concat_ws(thd, fields);
     /*
       Above function used only to get value and do not need fix_fields for it:
       Item_string - basic constant
@@ -6129,7 +6130,7 @@ void Item_func_match::init_search(bool no_order)
   if (master)
   {
     join_key= master->join_key= join_key | master->join_key;
-    master->init_search(no_order);
+    master->init_search(thd, no_order);
     ft_handler= master->ft_handler;
     join_key= master->join_key;
     DBUG_VOID_RETURN;
@@ -6464,7 +6465,7 @@ Item *get_system_var(THD *thd, enum_var_type var_type, LEX_STRING name,
 
   set_if_smaller(component_name->length, MAX_SYS_VAR_LENGTH);
 
-  return new Item_func_get_system_var(var, var_type, component_name,
+  return new Item_func_get_system_var(thd, var, var_type, component_name,
                                       NULL, 0);
 }
 
@@ -6480,8 +6481,9 @@ longlong Item_func_row_count::val_int()
 
 
 
-Item_func_sp::Item_func_sp(Name_resolution_context *context_arg, sp_name *name)
-  :Item_func(), context(context_arg), m_name(name), m_sp(NULL), sp_result_field(NULL)
+Item_func_sp::Item_func_sp(THD *thd, Name_resolution_context *context_arg,
+                           sp_name *name):
+  Item_func(thd), context(context_arg), m_name(name), m_sp(NULL), sp_result_field(NULL)
 {
   maybe_null= 1;
   m_name->init_qname(current_thd);
@@ -6490,10 +6492,10 @@ Item_func_sp::Item_func_sp(Name_resolution_context *context_arg, sp_name *name)
 }
 
 
-Item_func_sp::Item_func_sp(Name_resolution_context *context_arg,
-                           sp_name *name_arg, List<Item> &list)
-  :Item_func(list), context(context_arg), m_name(name_arg), m_sp(NULL),
-   sp_result_field(NULL)
+Item_func_sp::Item_func_sp(THD *thd, Name_resolution_context *context_arg,
+                           sp_name *name_arg, List<Item> &list):
+  Item_func(thd, list), context(context_arg), m_name(name_arg), m_sp(NULL),
+  sp_result_field(NULL)
 {
   maybe_null= 1;
   m_name->init_qname(current_thd);

sql/item_row.cc

@@ -146,13 +146,13 @@ void Item_row::print(String *str, enum_query_type query_type)
 }
 
 
-Item *Item_row::transform(Item_transformer transformer, uchar *arg)
+Item *Item_row::transform(THD *thd, Item_transformer transformer, uchar *arg)
 {
-  DBUG_ASSERT(!current_thd->stmt_arena->is_stmt_prepare());
+  DBUG_ASSERT(!thd->stmt_arena->is_stmt_prepare());
 
-  if (transform_args(transformer, arg))
+  if (transform_args(thd, transformer, arg))
     return 0;
-  return (this->*transformer)(arg);
+  return (this->*transformer)(thd, arg);
 }
 
 void Item_row::bring_value()

sql/item_row.h

@@ -35,10 +35,11 @@ class Item_row: public Item,
   table_map not_null_tables_cache;
   bool with_null;
 public:
-  Item_row(List<Item> &list)
-   :Item_args(list), not_null_tables_cache(0), with_null(0)
+  Item_row(THD *thd, List<Item> &list):
+   Item(thd), Item_args(list), not_null_tables_cache(0), with_null(0)
   { }
-  Item_row(Item_row *item):
+  Item_row(THD *thd, Item_row *item):
+    Item(thd),
     Item_args(item),
     Used_tables_and_const_cache(item),
     not_null_tables_cache(0),
@@ -95,7 +96,7 @@ public:
       return true;
     return (this->*processor)(arg);
   }
-  Item *transform(Item_transformer transformer, uchar *arg);
+  Item *transform(THD *thd, Item_transformer transformer, uchar *arg);
   bool eval_not_null_tables(uchar *opt_arg);
 
   uint cols() { return arg_count; }

sql/item_strfunc.cc

@@ -4273,9 +4273,9 @@ String *Item_func_uuid::val_str(String *str)
 }
 
 
-Item_func_dyncol_create::Item_func_dyncol_create(List<Item> &args,
-                                                 DYNCALL_CREATE_DEF *dfs)
-  : Item_str_func(args), defs(dfs), vals(0), keys_num(NULL), keys_str(NULL),
+Item_func_dyncol_create::Item_func_dyncol_create(THD *thd, List<Item> &args,
+                                                 DYNCALL_CREATE_DEF *dfs):
+  Item_str_func(thd, args), defs(dfs), vals(0), keys_num(NULL), keys_str(NULL),
   names(FALSE), force_names(FALSE)
 {
   DBUG_ASSERT((args.elements & 0x1) == 0); // even number of arguments

sql/item_xmlfunc.h

@@ -76,13 +76,12 @@ protected:
     return xml_arg->parse(args[0], cache);
   }
 public:
-  Item_xml_str_func(Item *a, Item *b): 
-    Item_str_func(a,b) 
+  Item_xml_str_func(THD *thd, Item *a, Item *b): Item_str_func(thd, a, b)
   {
     maybe_null= TRUE;
   }
-  Item_xml_str_func(Item *a, Item *b, Item *c): 
-    Item_str_func(a,b,c) 
+  Item_xml_str_func(THD *thd, Item *a, Item *b, Item *c):
+    Item_str_func(thd, a, b, c)
   {
     maybe_null= TRUE;
   }
@@ -102,7 +101,8 @@ public:
 class Item_func_xml_extractvalue: public Item_xml_str_func
 {
 public:
-  Item_func_xml_extractvalue(Item *a,Item *b) :Item_xml_str_func(a,b) {}
+  Item_func_xml_extractvalue(THD *thd, Item *a, Item *b):
+    Item_xml_str_func(thd, a, b) {}
   const char *func_name() const { return "extractvalue"; }
   String *val_str(String *);
 };
@@ -115,7 +115,8 @@ class Item_func_xml_update: public Item_xml_str_func
                       const MY_XML_NODE *cut,
                       const String *replace);
 public:
-  Item_func_xml_update(Item *a,Item *b,Item *c) :Item_xml_str_func(a,b,c) {}
+  Item_func_xml_update(THD *thd, Item *a, Item *b, Item *c):
+    Item_xml_str_func(thd, a, b, c) {}
   const char *func_name() const { return "updatexml"; }
   String *val_str(String *);
 };