From: kgeorge
Date: January 16 2007 11:44am
Subject: bk commit into 5.1 tree (gkodinov:1.2392) BUG#6172
List-Archive: http://lists.mysql.com/commits/18177
X-Bug: 6172
Message-Id: <20070116114426.8354EBCF9E0@macbook.gmz>

Below is the list of changes that have just been committed into a local
5.1 repository of kgeorge. When kgeorge does a push these changes will
be propagated to the main repository and, within 24 hours after the
push, to the public repository.
For information on how to access the public repository
see http://dev.mysql.com/doc/mysql/en/installing-source-tree.html

ChangeSet@stripped, 2007-01-16 13:44:06+02:00, gkodinov@stripped +4 -0
  Bug #6172: RAND(a) should only accept constant values as arguments
   RAND() must accept scalar expressions regardless of their kind.
   That includes both constant expressions and expressions that 
   depend on column values.
   When the expression is constant the random seed can be initialized
   at compile time.
   However when the expression is not constant the random seed must be
   initialized at each invocation (while it still can be allocated at
   compile time).
   Implemented the above rules by extending Item_func_rand::val_real()
   to initialize the random seed at the correct place.

  mysql-test/r/func_math.result@stripped, 2007-01-16 13:43:58+02:00, gkodinov@stripped +23 -5
    Bug #6172: RAND(a) should only accept constant values as arguments
     - extened the test case

  mysql-test/t/func_math.test@stripped, 2007-01-16 13:43:59+02:00, gkodinov@stripped +14 -5
    Bug #6172: RAND(a) should only accept constant values as arguments
     - extened the test case

  sql/item_func.cc@stripped, 2007-01-16 13:44:00+02:00, gkodinov@stripped +24 -19
    Bug #6172: RAND(a) should only accept constant values as arguments
     - allow specifying non-const expressions as RAND() arguments

  sql/item_func.h@stripped, 2007-01-16 13:44:00+02:00, gkodinov@stripped +2 -0
    Bug #6172: RAND(a) should only accept constant values as arguments
     - allow specifying non-const expressions as RAND() arguments

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	gkodinov
# Host:	macbook.gmz
# Root:	/Users/kgeorge/mysql/work/B6172-5.1-opt

--- 1.345/sql/item_func.cc	2007-01-10 12:06:17 +02:00
+++ 1.346/sql/item_func.cc	2007-01-16 13:44:00 +02:00
@@ -2042,6 +2042,25 @@ my_decimal *Item_func_round::decimal_op(
 }
 
 
+void Item_func_rand::seed_random(Item *arg)
+{
+  /*
+    PARAM_ITEM is returned if we're in statement prepare and consequently
+    no placeholder value is set yet.
+  */
+  if (arg->type() != PARAM_ITEM)
+  {
+    /*
+      TODO: do not do reinit 'rand' for every execute of PS/SP if
+      args[0] is a constant.
+    */
+    uint32 tmp= (uint32) arg->val_int();
+    randominit(rand, (uint32) (tmp*0x10001L+55555555L),
+               (uint32) (tmp*0x10000001L));
+  }
+}
+
+
 bool Item_func_rand::fix_fields(THD *thd,Item **ref)
 {
   if (Item_real_func::fix_fields(thd, ref))
@@ -2049,11 +2068,6 @@ bool Item_func_rand::fix_fields(THD *thd
   used_tables_cache|= RAND_TABLE_BIT;
   if (arg_count)
   {					// Only use argument once in query
-    if (!args[0]->const_during_execution())
-    {
-      my_error(ER_WRONG_ARGUMENTS, MYF(0), "RAND");
-      return TRUE;
-    }
     /*
       Allocate rand structure once: we must use thd->stmt_arena
       to create rand in proper mem_root if it's a prepared statement or
@@ -2065,20 +2079,9 @@ bool Item_func_rand::fix_fields(THD *thd
     if (!rand && !(rand= (struct rand_struct*)
                    thd->stmt_arena->alloc(sizeof(*rand))))
       return TRUE;
-    /*
-      PARAM_ITEM is returned if we're in statement prepare and consequently
-      no placeholder value is set yet.
-    */
-    if (args[0]->type() != PARAM_ITEM)
-    {
-      /*
-        TODO: do not do reinit 'rand' for every execute of PS/SP if
-        args[0] is a constant.
-      */
-      uint32 tmp= (uint32) args[0]->val_int();
-      randominit(rand, (uint32) (tmp*0x10001L+55555555L),
-                 (uint32) (tmp*0x10000001L));
-    }
+
+    if (args[0]->const_during_execution())
+      seed_random (args[0]);
   }
   else
   {
@@ -2108,6 +2111,8 @@ void Item_func_rand::update_used_tables(
 double Item_func_rand::val_real()
 {
   DBUG_ASSERT(fixed == 1);
+  if (arg_count && !args[0]->const_during_execution())
+    seed_random (args[0]);
   return my_rnd(rand);
 }
 

--- 1.160/sql/item_func.h	2007-01-10 12:06:17 +02:00
+++ 1.161/sql/item_func.h	2007-01-16 13:44:00 +02:00
@@ -679,6 +679,8 @@ public:
   bool const_item() const { return 0; }
   void update_used_tables();
   bool fix_fields(THD *thd, Item **ref);
+private:
+  void seed_random (Item * val);  
 };
 
 

--- 1.39/mysql-test/r/func_math.result	2006-11-02 20:01:48 +02:00
+++ 1.40/mysql-test/r/func_math.result	2007-01-16 13:43:58 +02:00
@@ -177,11 +177,29 @@ drop table t1;
 select abs(-2) * -2;
 abs(-2) * -2
 -4
-create table t1 (i int);
-insert into t1 values (1);
-select rand(i) from t1;
-ERROR HY000: Incorrect arguments to RAND
-drop table t1;
+CREATE TABLE t1 (a INT);
+INSERT INTO t1 VALUES (1),(2);
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+FROM t1;
+CAST(RAND(2) * 1000 AS UNSIGNED)	CAST(RAND(a) * 1000 AS UNSIGNED)
+656	405
+122	656
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+FROM t1 WHERE a = 1;
+CAST(RAND(2) * 1000 AS UNSIGNED)	CAST(RAND(a) * 1000 AS UNSIGNED)
+656	405
+INSERT INTO t1 VALUES (3);
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+FROM t1;
+CAST(RAND(2) * 1000 AS UNSIGNED)	CAST(RAND(a) * 1000 AS UNSIGNED)
+656	405
+122	656
+645	906
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+FROM t1 WHERE a = 1;
+CAST(RAND(2) * 1000 AS UNSIGNED)	CAST(RAND(a) * 1000 AS UNSIGNED)
+656	405
+DROP TABLE t1;
 create table t1 (a varchar(90), ts datetime not null, index (a)) engine=innodb default charset=utf8;
 insert into t1 values ('http://www.foo.com/', now());
 select a from t1 where a='http://www.foo.com/' order by abs(timediff(ts, 0));

--- 1.28/mysql-test/t/func_math.test	2006-11-02 20:01:49 +02:00
+++ 1.29/mysql-test/t/func_math.test	2007-01-16 13:43:59 +02:00
@@ -115,11 +115,20 @@ select abs(-2) * -2;
 #
 # Bug #6172 RAND(a) should only accept constant values as arguments
 #
-create table t1 (i int);
-insert into t1 values (1);
---error 1210
-select rand(i) from t1;
-drop table t1;
+CREATE TABLE t1 (a INT);
+
+INSERT INTO t1 VALUES (1),(2);
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+  FROM t1;
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+  FROM t1 WHERE a = 1;
+INSERT INTO t1 VALUES (3);
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+  FROM t1;
+SELECT CAST(RAND(2) * 1000 AS UNSIGNED), CAST(RAND(a) * 1000 AS UNSIGNED) 
+  FROM t1 WHERE a = 1;
+
+DROP TABLE t1;  
 
 #
 # Bug #14009: use of abs() on null value causes problems with filesort