Merge mysql.com:/usr_rh9/home/elkin.rh9/MySQL/FIXES/5.0.20-bug15101-sysdate

into  mysql.com:/usr_rh9/home/elkin.rh9/MySQL/Merge/5.1

mysql-test/r/sysdate_is_now.result

+set timestamp=1;
+SELECT sleep(1),NOW()-SYSDATE() as zero;
+sleep(1)	zero
+0	0

mysql-test/t/sysdate_is_now-master.opt

+--sysdate-is-now

mysql-test/t/sysdate_is_now.test

+#
+# BUG#15101 restore aliasing of SYSDATE to NOW in 5.0
+# this feature is activated via --sysdate-is-now mysqld init opt
+#
+# To test here
+# 1. SYSDATE() does not distiguish from NOW()
+# 2. SYSDATE() obeys set timestamp
+
+set timestamp=1;
+SELECT sleep(1),NOW()-SYSDATE() as zero;
+# End of 5.0 tests

sql/mysqld.cc

@@ -4800,6 +4800,7 @@ enum options_mysqld
   OPT_DATETIME_FORMAT,
   OPT_LOG_QUERIES_NOT_USING_INDEXES,
   OPT_DEFAULT_TIME_ZONE,
+  OPT_SYSDATE_IS_NOW,
   OPT_OPTIMIZER_SEARCH_DEPTH,
   OPT_OPTIMIZER_PRUNE_LEVEL,
   OPT_UPDATABLE_VIEWS_WITH_LIMIT,
@@ -6291,6 +6292,10 @@ The minimum value for this variable is 4096.",
    (gptr*) &max_system_variables.net_wait_timeout, 0, GET_ULONG,
    REQUIRED_ARG, NET_WAIT_TIMEOUT, 1, IF_WIN(INT_MAX32/1000, LONG_TIMEOUT),
    0, 1, 0},
+  {"sysdate-is-now", OPT_SYSDATE_IS_NOW,
+   "Non-default flag to alias SYSDATE() to NOW() to be safe-replicatable. Since 5.0 SYSDATE returns a `dynamic' value different for different invocation even within a query",
+   (gptr*) &global_system_variables.sysdate_is_now,
+   0, 0, GET_BOOL, NO_ARG, 0, 0, 1, 0, 1, 0},
   {0, 0, 0, 0, 0, 0, GET_NO_ARG, NO_ARG, 0, 0, 0, 0, 0, 0}
 };
 

sql/sql_class.h

@@ -276,6 +276,7 @@ struct system_variables
   DATE_TIME_FORMAT *date_format;
   DATE_TIME_FORMAT *datetime_format;
   DATE_TIME_FORMAT *time_format;
+  my_bool sysdate_is_now;
 };
 
 

sql/sql_yacc.yy

@@ -6342,9 +6342,19 @@ simple_expr:
 	| SUBSTRING_INDEX '(' expr ',' expr ',' expr ')'
 	  { $$= new Item_func_substr_index($3,$5,$7); }
 	| SYSDATE optional_braces
-	  { $$= new Item_func_sysdate_local(); Lex->safe_to_cache_query=0;}
+          {
+            if (global_system_variables.sysdate_is_now == 0)
+              $$= new Item_func_sysdate_local();
+            else $$= new Item_func_now_local();
+            Lex->safe_to_cache_query=0;
+          }
 	| SYSDATE '(' expr ')'
-	  { $$= new Item_func_sysdate_local($3); Lex->safe_to_cache_query=0;}
+          {
+            if (global_system_variables.sysdate_is_now == 0)
+              $$= new Item_func_sysdate_local($3);
+            else $$= new Item_func_now_local($3);
+            Lex->safe_to_cache_query=0;
+          }
 	| TIME_SYM '(' expr ')'
 	  { $$= new Item_time_typecast($3); }
 	| TIMESTAMP '(' expr ')'