Add SLEEP(seconds) function, which always returns 0 after the given

number of seconds (which can include microseconds). (Bug #6760)

mysql-test/r/func_misc.result

@@ -59,3 +59,14 @@ t1	CREATE TABLE `t1` (
   `length(uuid())` int(10) NOT NULL default '0'
 ) ENGINE=MyISAM DEFAULT CHARSET=latin1
 drop table t1;
+create table t1 (a timestamp default '2005-05-05 01:01:01',
+b timestamp default '2005-05-05 01:01:01');
+insert into t1 set a = now();
+select sleep(3);
+sleep(3)
+0
+update t1 set b = now();
+select timediff(b, a) >= '00:00:03' from t1;
+timediff(b, a) >= '00:00:03'
+1
+drop table t1;

mysql-test/t/func_misc.test

@@ -46,3 +46,12 @@ drop table t1;
 create table t1 as select uuid(), length(uuid());
 show create table t1;
 drop table t1;
+
+# Bug #6760: Add SLEEP() function
+create table t1 (a timestamp default '2005-05-05 01:01:01',
+                 b timestamp default '2005-05-05 01:01:01');
+insert into t1 set a = now();
+select sleep(3);
+update t1 set b = now();
+select timediff(b, a) >= '00:00:03' from t1;
+drop table t1;

sql/item_create.cc

@@ -354,6 +354,11 @@ Item *create_func_sha(Item* a)
   return new Item_func_sha(a);
 }
 
+Item *create_func_sleep(Item* a)
+{
+  return new Item_func_sleep(a);
+}
+
 Item *create_func_space(Item *a)
 {
   CHARSET_INFO *cs= current_thd->variables.collation_connection;

sql/item_create.h

@@ -83,6 +83,7 @@ Item *create_func_sec_to_time(Item* a);
 Item *create_func_sign(Item* a);
 Item *create_func_sin(Item* a);
 Item *create_func_sha(Item* a);
+Item *create_func_sleep(Item* a);
 Item *create_func_soundex(Item* a);
 Item *create_func_space(Item *);
 Item *create_func_sqrt(Item* a);

sql/item_func.cc

@@ -3259,6 +3259,17 @@ void Item_func_benchmark::print(String *str)
   str->append(')');
 }
 
+/* This function is just used to create tests with time gaps */
+
+longlong Item_func_sleep::val_int()
+{
+  DBUG_ASSERT(fixed == 1);
+  double time= args[0]->val_real();
+  my_sleep((ulong)time*1000000L);
+  return 0;
+}
+
+
 #define extra_size sizeof(double)
 
 static user_var_entry *get_variable(HASH *hash, LEX_STRING &name,

sql/item_func.h

@@ -874,6 +874,7 @@ class Item_func_last_insert_id :public Item_int_func
   }
 };
 
+
 class Item_func_benchmark :public Item_int_func
 {
   ulong loop_count;
@@ -888,6 +889,16 @@ class Item_func_benchmark :public Item_int_func
 };
 
 
+class Item_func_sleep :public Item_int_func
+{
+public:
+  Item_func_sleep(Item *a) :Item_int_func(a) {}
+  const char *func_name() const { return "sleep"; }
+  longlong val_int();
+};
+
+
+
 #ifdef HAVE_DLOPEN
 
 class Item_udf_func :public Item_func

sql/lex.h

@@ -734,6 +734,7 @@ static SYMBOL sql_functions[] = {
   { "SIN",		F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_sin)},
   { "SHA",              F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_sha)},
   { "SHA1",             F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_sha)},
+  { "SLEEP",            F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_sleep)},
   { "SOUNDEX",		F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_soundex)},
   { "SPACE",		F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_space)},
   { "SQRT",		F_SYM(FUNC_ARG1),0,CREATE_FUNC(create_func_sqrt)},