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Bug#26093 (SELECT BENCHMARK() for SELECT statements does not produce valid

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results)

Before this fix, the function BENCHMARK() would fail to evaluate expressions
like "(select avg(a) from t1)" in debug builds (with an assert),
or would report a time of zero in non debug builds.

The root cause is that evaluation of DECIMAL_RESULT expressions was not
supported in Item_func_benchmark::val_int().

This has been fixed by this change.


mysql-test/r/func_misc.result:
  Added support for DECIMAL_RESULT in Item_func_benchmark::val_int()
mysql-test/t/func_misc.test:
  Added support for DECIMAL_RESULT in Item_func_benchmark::val_int()
sql/item_func.cc:
  Added support for DECIMAL_RESULT in Item_func_benchmark::val_int()
This commit is contained in:
unknown 2007-03-01 19:20:47 -07:00
commit 0a93be2869
3 changed files with 105 additions and 0 deletions
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44
mysql-test/r/func_misc.result
View file

@ -141,4 +141,48 @@ t1 CREATE TABLE `t1` (
`a` bigint(21) unsigned default NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
drop table t1;
drop table if exists table_26093;
drop function if exists func_26093_a;
drop function if exists func_26093_b;
create table table_26093(a int);
insert into table_26093 values
(1), (2), (3), (4), (5),
(6), (7), (8), (9), (10);
create function func_26093_a(x int) returns int
begin
set @invoked := @invoked + 1;
return x;
end//
create function func_26093_b(x int, y int) returns int
begin
set @invoked := @invoked + 1;
return x;
end//
select avg(a) from table_26093;
avg(a)
5.5000
select benchmark(100, (select avg(a) from table_26093));
benchmark(100, (select avg(a) from table_26093))
0
set @invoked := 0;
select benchmark(100, (select avg(func_26093_a(a)) from table_26093));
benchmark(100, (select avg(func_26093_a(a)) from table_26093))
0
select @invoked;
@invoked
10
set @invoked := 0;
select benchmark(100, (select avg(func_26093_b(a, rand())) from table_26093));
benchmark(100, (select avg(func_26093_b(a, rand())) from table_26093))
0
select @invoked;
@invoked
1000
select benchmark(100, (select (a) from table_26093));
ERROR 21000: Subquery returns more than 1 row
select benchmark(100, (select 1, 1));
ERROR 21000: Operand should contain 1 column(s)
drop table table_26093;
drop function func_26093_a;
drop function func_26093_b;
End of 5.0 tests

57
mysql-test/t/func_misc.test
View file

@ -132,4 +132,61 @@ set global query_cache_size=default;
create table t1 select INET_ATON('255.255.0.1') as `a`;
show create table t1;
drop table t1;
#
# Bug#26093 (SELECT BENCHMARK() for SELECT statements does not produce
# valid results)
#
--disable_warnings
drop table if exists table_26093;
drop function if exists func_26093_a;
drop function if exists func_26093_b;
--enable_warnings
create table table_26093(a int);
insert into table_26093 values
(1), (2), (3), (4), (5),
(6), (7), (8), (9), (10);
delimiter //;
create function func_26093_a(x int) returns int
begin
set @invoked := @invoked + 1;
return x;
end//
create function func_26093_b(x int, y int) returns int
begin
set @invoked := @invoked + 1;
return x;
end//
delimiter ;//
select avg(a) from table_26093;
select benchmark(100, (select avg(a) from table_26093));
set @invoked := 0;
select benchmark(100, (select avg(func_26093_a(a)) from table_26093));
# Returns only 10, since intermediate results are cached.
select @invoked;
set @invoked := 0;
select benchmark(100, (select avg(func_26093_b(a, rand())) from table_26093));
# Returns 1000, due to rand() preventing caching.
select @invoked;
--error ER_SUBQUERY_NO_1_ROW
select benchmark(100, (select (a) from table_26093));
--error ER_OPERAND_COLUMNS
select benchmark(100, (select 1, 1));
drop table table_26093;
drop function func_26093_a;
drop function func_26093_b;
--echo End of 5.0 tests

4
sql/item_func.cc
View file

@ -3456,6 +3456,7 @@ longlong Item_func_benchmark::val_int()
DBUG_ASSERT(fixed == 1);
char buff[MAX_FIELD_WIDTH];
String tmp(buff,sizeof(buff), &my_charset_bin);
my_decimal tmp_decimal;
THD *thd=current_thd;
for (ulong loop=0 ; loop < loop_count && !thd->killed; loop++)
@ -3470,6 +3471,9 @@ longlong Item_func_benchmark::val_int()
case STRING_RESULT:
(void) args[0]->val_str(&tmp);
break;
case DECIMAL_RESULT:
(void) args[0]->val_decimal(&tmp_decimal);
break;
case ROW_RESULT:
default:
// This case should never be chosen