Bug #28897 UUID() returns non-unique values when query cache is enabled

Removed the ability to cache queries containing "UUID()".


mysql-test/r/query_cache.result:
  Added test to ensure "select UUID(), a from t1" is different each time.
mysql-test/t/query_cache.test:
  Added test to ensure "select UUID(), a from t1" is different each time.
sql/item_create.cc:
  Removed the ability to cache queries with UUID().

mysql-test/r/query_cache.result

@@ -1405,7 +1405,14 @@ Only MyISAM tables	support collections	1
 Function MATCH ... AGAINST()	is used to do a search	1
 Full-text search in MySQL	implements vector space model	1
 drop function change_global;
+drop table t1;
 set GLOBAL query_cache_type=default;
 set GLOBAL query_cache_limit=default;
 set GLOBAL query_cache_min_res_unit=default;
 set GLOBAL query_cache_size= default;
+set GLOBAL query_cache_size=1000000;
+create table t1 (a char);
+insert into t1 values ('c');
+a
+drop table t1;
+set GLOBAL query_cache_size= default;

mysql-test/t/query_cache.test

@@ -965,9 +965,33 @@ delimiter ;|
 select *, change_global() from t1;
 drop function change_global;
 
+drop table t1;
+
 set GLOBAL query_cache_type=default;
 set GLOBAL query_cache_limit=default;
 set GLOBAL query_cache_min_res_unit=default;
 set GLOBAL query_cache_size= default;
 
+
+#
+# Bug #28897  	UUID() returns non-unique values when query cache is enabled
+#
+
+set GLOBAL query_cache_size=1000000;
+
+create table t1 (a char);
+insert into t1 values ('c');
+
+let $q1= `select UUID(), a from t1`;
+let $q2= `select UUID(), a from t1`; 
+
+# disabling the logging of the query because the UUIDs are different each run.
+--disable_query_log
+eval select a  from t1 where "$q1" = "$q2";
+--enable_query_log
+
+drop table t1;
+
+set GLOBAL query_cache_size= default;
+
 # End of 5.0 tests

sql/item_create.cc

@@ -418,6 +418,7 @@ Item *create_func_unhex(Item* a)
 
 Item *create_func_uuid(void)
 {
+  current_thd->lex->safe_to_cache_query= 0;
   return new Item_func_uuid();
 }