after-review fixes

sql/sql_class.cc

@@ -86,8 +86,7 @@ extern "C" void free_user_var(user_var_entry *entry)
 ** Thread specific functions
 ****************************************************************************/
 
-THD::THD():user_time(0),
-           is_fatal_error(0),
+THD::THD():user_time(0), is_fatal_error(0),
 	   last_insert_id_used(0),
 	   insert_id_used(0), rand_used(0), in_lock_tables(0),
 	   global_read_lock(0), bootstrap(0), spcont(NULL)
@@ -108,6 +107,7 @@ THD::THD():user_time(0),
   cuted_fields= sent_row_count= 0L;
   statement_id_counter= 0UL;
   // Must be reset to handle error with THD's created for init of mysqld
+  lex->current_select= 0;
   start_time=(time_t) 0;
   current_linfo =  0;
   slave_thread = 0;
@@ -339,12 +339,12 @@ THD::~THD()
     safeFree(user);
   safeFree(db);
   safeFree(ip);
-  free_root(&warn_root,MYF(0));
-  free_root(&transaction.mem_root,MYF(0));
-  mysys_var=0;					// Safety (shouldn't be needed)
+  free_root(&warn_root, MYF(0));
+  free_root(&transaction.mem_root, MYF(0));
+  mysys_var= 0;					// Safety (shouldn't be needed)
   pthread_mutex_destroy(&LOCK_delete);
 #ifndef DBUG_OFF
-  dbug_sentry = THD_SENTRY_GONE;
+  dbug_sentry= THD_SENTRY_GONE;
 #endif  
   DBUG_VOID_RETURN;
 }
@@ -1277,23 +1277,17 @@ Statement::Statement(THD *thd)
   query_id(0),                                  /* initialized later */
   set_query_id(1),
   allow_sum_func(0),                            /* initialized later */
-  command(COM_SLEEP),     /* reset in THD counstructor and mysql_parse */
+  command(COM_SLEEP),                           /* initialized later */ 
   lex(&main_lex),
-  query(0),
-  query_length(0),
-  free_list(0)                                 /* reset in THD constructor */
+  query(0),                                     /* these two are set */
+  query_length(0),                              /* in alloc_query() */ 
+  free_list(0)
 {
   init_sql_alloc(&mem_root,
                  thd->variables.query_alloc_block_size,
                  thd->variables.query_prealloc_size);
 }
 
-/*
-  This constructor is called when statement is a subobject of THD:
-  Some variables are initialized in THD::init due to locking problems
-  This statement object will be used to hold state of currently active
-  statement.
-*/
 
 Statement::Statement()
   :id(0),
@@ -1329,9 +1323,11 @@ get_statement_id_as_hash_key(const byte *record, uint *key_length,
 
 C_MODE_END
 
+
 Statement_map::Statement_map()
 {
   enum { START_HASH_SIZE = 16 };
   hash_init(&st_hash, default_charset_info, START_HASH_SIZE, 0, 0,
             get_statement_id_as_hash_key, (hash_free_key) 0, MYF(0));
 }
+

sql/sql_class.h

@@ -454,22 +454,22 @@ public:
   LEX     main_lex;
 public:
   /*
-    Uniquely identifies each statement object in scope of thread.
-    Can't be const at the moment because of substitute() method
+    Uniquely identifies each statement object in thread scope; change during
+    statement lifetime.
   */
-  /* const */ ulong id;
+   ulong id;
 
   /*
-    Id of current query. Statement can be reused to execute several queries
+    Id of current query. Statement can be reused to execute several queries.
     query_id is global in context of the whole MySQL server.
-    ID is automatically generated from mutex-protected counter.
+    Id is automatically generated from mutex-protected counter.
     It's used in handler code for various purposes: to check which columns
     from table are necessary for this select, to check if it's necessary to
     update auto-updatable fields (like auto_increment and timestamp).
   */
   ulong query_id;
   /*
-    - if set_query_id=1, we set field->query_id for all fields. In that case 
+    - if set_query_id == 1, we set field->query_id for all fields. In that case 
     field list can not contain duplicates.
   */
   bool set_query_id;
@@ -487,8 +487,8 @@ public:
   */
   bool allow_sum_func;
   /*
-    Type of current query: COM_PREPARE, COM_QUERY, etc. Set from 
-    first byte of the packet in do_command()
+    Type of current query: COM_PREPARE, COM_QUERY, etc. Set from the
+    first byte of the incoming packet in do_command()
   */
   enum enum_server_command command;
 
@@ -508,6 +508,10 @@ public:
   MEM_ROOT mem_root;
 
 protected:
+  /*
+    This constructor is called when statement is a subobject of THD:
+    some variables are initialized in THD::init due to locking problems
+  */
   Statement();
 public:
   Statement(THD *thd);
@@ -529,7 +533,7 @@ public:
   {
     return my_hash_insert(&st_hash, (byte *) statement);
   }
-  Statement *seek(ulonglong id)
+  Statement *seek(ulong id)
   {
     return (Statement *) hash_search(&st_hash, (byte *) &id, sizeof(id));
   }
@@ -685,6 +689,12 @@ public:
   USER_CONN *user_connect;
   CHARSET_INFO *db_charset;
   List<TABLE> temporary_tables_should_be_free; // list of temporary tables
+  /*
+    FIXME: this, and some other variables like 'count_cuted_fields'
+    maybe should be statement/cursor local, that is, moved to Statement
+    class.  With current implementation warnings produced in each prepared
+    statement/ cursor settle here.
+  */
   List	     <MYSQL_ERROR> warn_list;
   uint	     warn_count[(uint) MYSQL_ERROR::WARN_LEVEL_END];
   uint	     total_warn_count;