Fixed reentrantness bugs in select (lex->result) and select_dumpvar, and added cool

prime number test example.


mysql-test/r/sp.result:
  New prime number example. (Good for future benchmarkings too.)
mysql-test/t/sp.test:
  New prime number example. (Good for future benchmarkings too.)
sql/sql_class.cc:
  Reset row_count in select_dumpvar when preparing, to make it reentrant as a lex member.
sql/sql_select.cc:
  Don't delete result if it's a lex member (since lex needs to be reentrant).

mysql-test/r/sp.result

@@ -170,13 +170,6 @@ insert into test.t1 values (repeat("b2",3), x);
 set x = x-1;
 until x = 0 end repeat;
 drop procedure b2;
-create procedure b3(x int)
-repeat
-select * from test.t1;	# No INTO!
-insert into test.t1 values (repeat("b3",3), x);
-set x = x-1;
-until x = 0 end repeat;
-SELECT in a stored procedure must have INTO
 create procedure c(x int)
 hmm: while x > 0 do
 insert into test.t1 values ("c", x);
@@ -431,5 +424,74 @@ n	f
 drop table fac;
 drop procedure ifac;
 drop function fac;
+drop table if exists primes;
+create table primes (
+i int unsigned not null primary key,
+p bigint unsigned not null
+);
+insert into primes values
+( 0,   3), ( 1,   5), ( 2,   7), ( 3,  11), ( 4,  13),
+( 5,  17), ( 6,  19), ( 7,  23), ( 8,  29), ( 9,  31),
+(10,  37), (11,  41), (12,  43), (13,  47), (14,  53),
+(15,  59), (16,  61), (17,  67), (18,  71), (19,  73),
+(20,  79), (21,  83), (22,  89), (23,  97), (24, 101),
+(25, 103), (26, 107), (27, 109), (28, 113), (29, 127),
+(30, 131), (31, 137), (32, 139), (33, 149), (34, 151),
+(35, 157), (36, 163), (37, 167), (38, 173), (39, 179),
+(40, 181), (41, 191), (42, 193), (43, 197), (44, 199);
+create procedure opp(n bigint unsigned, out pp bool)
+begin
+declare r double;
+declare b, s bigint unsigned;
+set b = 0, s = 0;
+set r = sqrt(n);
+again:
+loop
+if s = 45 then
+set b = b+200, s = 0;
+else
+begin
+declare p bigint unsigned;
+select t.p into p from test.primes t where t.i = s;
+if b+p > r then
+set pp = 1;
+leave again;
+end if;
+if mod(n, b+p) = 0 then
+set pp = 0;
+leave again;
+end if;
+set s = s+1;
+end;
+end if;
+end loop again;
+end;
+create procedure ip(m int unsigned)
+begin
+declare p bigint unsigned;
+declare i int unsigned;
+set i=45, p=201;
+while i < m do
+begin
+declare pp bool;
+set pp = 0;
+call opp(p, pp);
+if pp then
+insert into test.primes values (i, p);
+set i = i+1;
+end if;
+set p = p+2;
+end;
+end while;
+end;
+call ip(200);
+select * from primes where i=45 or i=100 or i=199;
+i	p
+45	211
+100	557
+199	1229
+drop table primes;
+drop procedure opp;
+drop procedure ip;
 drop table t1;
 drop table t2;

mysql-test/t/sp.test

@@ -454,7 +454,11 @@ drop function append|
 drop function fun|
 
 
-# A "real" procedure and function example
+#
+# Some "real" examples
+#
+
+# fac
 
 --disable_warnings
 drop table if exists fac|
@@ -482,6 +486,92 @@ drop table fac|
 drop procedure ifac|
 drop function fac|
 
+
+# primes
+
+--disable_warnings
+drop table if exists primes|
+--enable_warnings
+
+create table primes (
+  i int unsigned not null primary key,
+  p bigint unsigned not null
+)|
+
+insert into primes values
+ ( 0,   3), ( 1,   5), ( 2,   7), ( 3,  11), ( 4,  13),
+ ( 5,  17), ( 6,  19), ( 7,  23), ( 8,  29), ( 9,  31),
+ (10,  37), (11,  41), (12,  43), (13,  47), (14,  53),
+ (15,  59), (16,  61), (17,  67), (18,  71), (19,  73),
+ (20,  79), (21,  83), (22,  89), (23,  97), (24, 101),
+ (25, 103), (26, 107), (27, 109), (28, 113), (29, 127),
+ (30, 131), (31, 137), (32, 139), (33, 149), (34, 151),
+ (35, 157), (36, 163), (37, 167), (38, 173), (39, 179),
+ (40, 181), (41, 191), (42, 193), (43, 197), (44, 199)|
+
+create procedure opp(n bigint unsigned, out pp bool)
+begin
+  declare r double;
+  declare b, s bigint unsigned;
+
+  set b = 0, s = 0;
+  set r = sqrt(n);
+
+ again:
+  loop
+    if s = 45 then
+      set b = b+200, s = 0;
+    else
+      begin
+        declare p bigint unsigned;
+
+        select t.p into p from test.primes t where t.i = s;
+        if b+p > r then
+          set pp = 1;
+          leave again;
+        end if;
+        if mod(n, b+p) = 0 then
+          set pp = 0;
+          leave again;
+        end if;
+        set s = s+1;
+      end;
+    end if;
+  end loop again;
+end|
+
+create procedure ip(m int unsigned)
+begin
+  declare p bigint unsigned;
+  declare i int unsigned;
+
+  set i=45, p=201;
+
+  while i < m do
+    begin
+      declare pp bool;
+
+      set pp = 0;
+      call opp(p, pp);
+      if pp then
+        insert into test.primes values (i, p);
+        set i = i+1;
+      end if;
+      set p = p+2;
+    end;
+  end while;
+end|
+
+# This isn't the fastest way in the world to compute prime numbers, so
+# don't be too ambition. ;-)
+call ip(200)|
+# We don't want to select the entire table here, just pick a few
+# examples.
+select * from primes where i=45 or i=100 or i=199|
+drop table primes|
+drop procedure opp|
+drop procedure ip|
+
 delimiter ;|
 drop table t1;
 drop table t2;

sql/sql_class.cc

@@ -972,6 +972,8 @@ int select_dumpvar::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
   Item *item;
   my_var *mv;
   LEX_STRING *ls;
+
+  row_count= 0;
   if (var_list.elements != list.elements)
   {
     my_error(ER_WRONG_NUMBER_OF_COLUMNS_IN_SELECT, MYF(0));
@@ -996,6 +998,7 @@ int select_dumpvar::prepare(List<Item> &list, SELECT_LEX_UNIT *u)
   }
   return 0;
 }
+
 bool select_dumpvar::send_data(List<Item> &items)
 {
   List_iterator_fast<Item_func_set_user_var> li(vars);

sql/sql_select.cc

@@ -191,6 +191,7 @@ int handle_select(THD *thd, LEX *lex, select_result *result)
     send_error(thd, 0, NullS);
     res= 1;
   }
+  if (result != lex->result)
     delete result;
   return res;
 }