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Bug#30237 (Performance regression in boolean expressions) 

This is a performance bug, related to the parsing or 'OR' and 'AND' boolean
expressions.

Let N be the number of expressions involved in a OR (respectively AND).

When N=1

For example, "select 1" involve only 1 term: there is no OR operator.

In 4.0 and 4.1, parsing expressions not involving OR had no overhead.
In 5.0, parsing adds some overhead, with Select->expr_list.

With this patch, the overhead introduced in 5.0 has been removed,
so that performances for N=1 should be identical to the 4.0 performances,
which are optimal (there is no code executed at all)

The overhead in 5.0 was in fact affecting significantly some operations.
For example, loading 1 Million rows into a table with INSERTs,
for a table that has 100 columns, leads to parsing 100 Millions of
expressions, which means that the overhead related to Select->expr_list
is executed 100 Million times ...

Considering that N=1 is by far the most probable expression,
this case should be optimal.

When N=2

For example, "select a OR b" involves 2 terms in the OR operator.

In 4.0 and 4.1, parsing expressions involving 2 terms created 1 Item_cond_or
node, which is the expected result.
In 5.0, parsing these expression also produced 1 node, but with some extra
overhead related to Select->expr_list : creating 1 list in Select->expr_list
and another in Item_cond::list is inefficient.

With this patch, the overhead introduced in 5.0 has been removed
so that performances for N=2 should be identical to the 4.0 performances.
Note that the memory allocation uses the new (thd->mem_root) syntax
directly.
The cost of "is_cond_or" is estimated to be neglectable: the real problem
of the performance degradation comes from unneeded memory allocations.

When N>=3

For example, "select a OR b OR c ...", which involves 3 or more terms.

In 4.0 and 4.1, the parser had no significant cost overhead, but produced
an Item tree which is difficult to evaluate / optimize during runtime.
In 5.0, the parser produces a better Item tree, using the Item_cond
constructor that accepts a list of children directly, but at an extra cost
related to Select->expr_list.

With this patch, the code is implemented to take the best of the two
implementations:
- there is no overhead with Select->expr_list
- the Item tree generated is optimized and flattened.

This is achieved by adding children nodes into the Item tree directly,
with Item_cond::add(), which avoids the need for temporary lists and memory
allocation

Note that this patch also provide an extra optimization, that the previous
code in 5.0 did not provide: expressions are flattened in the Item tree,
based on what the expression already parsed is, and not based on the order
in which rules are reduced.

For example : "(a OR b) OR c", "a OR (b OR c)" would both be represented
with 2 Item_cond_or nodes before this patch, and with 1 node only with this
patch. The logic used is based on the mathematical properties of the OR
operator (it's associative), and produces a simpler tree.


sql/item_cmpfunc.h:
  Improved performances for parsing boolean expressions
sql/sql_yacc.yy:
  Improved performances for parsing boolean expressions
mysql-test/r/parser_precedence.result:
  Added test cases to cover boolean operator precedence
mysql-test/t/parser_precedence.test:
  Added test cases to cover boolean operator precedence
parent b78131c4
Hide whitespace changes
Inline Side-by-side
Showing with 564 additions and 43 deletions
mysql-test/r/parser_precedence.result 0 → 100644
View file @ fb1be0f1
drop table if exists t1_30237_bool;
create table t1_30237_bool(A boolean, B boolean, C boolean);
insert into t1_30237_bool values
(FALSE, FALSE, FALSE),
(FALSE, FALSE, NULL),
(FALSE, FALSE, TRUE),
(FALSE, NULL, FALSE),
(FALSE, NULL, NULL),
(FALSE, NULL, TRUE),
(FALSE, TRUE, FALSE),
(FALSE, TRUE, NULL),
(FALSE, TRUE, TRUE),
(NULL, FALSE, FALSE),
(NULL, FALSE, NULL),
(NULL, FALSE, TRUE),
(NULL, NULL, FALSE),
(NULL, NULL, NULL),
(NULL, NULL, TRUE),
(NULL, TRUE, FALSE),
(NULL, TRUE, NULL),
(NULL, TRUE, TRUE),
(TRUE, FALSE, FALSE),
(TRUE, FALSE, NULL),
(TRUE, FALSE, TRUE),
(TRUE, NULL, FALSE),
(TRUE, NULL, NULL),
(TRUE, NULL, TRUE),
(TRUE, TRUE, FALSE),
(TRUE, TRUE, NULL),
(TRUE, TRUE, TRUE) ;
Testing OR, XOR, AND
select A, B, A OR B, A XOR B, A AND B
from t1_30237_bool where C is null order by A, B;
A B A OR B A XOR B A AND B
NULL NULL NULL NULL NULL
NULL 0 NULL NULL 0
NULL 1 1 NULL NULL
0 NULL NULL NULL 0
0 0 0 0 0
0 1 1 1 0
1 NULL 1 NULL NULL
1 0 1 1 0
1 1 1 0 1
Testing that OR is associative
select A, B, C, (A OR B) OR C, A OR (B OR C), A OR B OR C
from t1_30237_bool order by A, B, C;
A B C (A OR B) OR C A OR (B OR C) A OR B OR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 1 1 1
NULL 0 NULL NULL NULL NULL
NULL 0 0 NULL NULL NULL
NULL 0 1 1 1 1
NULL 1 NULL 1 1 1
NULL 1 0 1 1 1
NULL 1 1 1 1 1
0 NULL NULL NULL NULL NULL
0 NULL 0 NULL NULL NULL
0 NULL 1 1 1 1
0 0 NULL NULL NULL NULL
0 0 0 0 0 0
0 0 1 1 1 1
0 1 NULL 1 1 1
0 1 0 1 1 1
0 1 1 1 1 1
1 NULL NULL 1 1 1
1 NULL 0 1 1 1
1 NULL 1 1 1 1
1 0 NULL 1 1 1
1 0 0 1 1 1
1 0 1 1 1 1
1 1 NULL 1 1 1
1 1 0 1 1 1
1 1 1 1 1 1
select count(*) from t1_30237_bool
where ((A OR B) OR C) != (A OR (B OR C));
count(*)
0
Testing that XOR is associative
select A, B, C, (A XOR B) XOR C, A XOR (B XOR C), A XOR B XOR C
from t1_30237_bool order by A, B, C;
A B C (A XOR B) XOR C A XOR (B XOR C) A XOR B XOR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 NULL NULL NULL
NULL 0 NULL NULL NULL NULL
NULL 0 0 NULL NULL NULL
NULL 0 1 NULL NULL NULL
NULL 1 NULL NULL NULL NULL
NULL 1 0 NULL NULL NULL
NULL 1 1 NULL NULL NULL
0 NULL NULL NULL NULL NULL
0 NULL 0 NULL NULL NULL
0 NULL 1 NULL NULL NULL
0 0 NULL NULL NULL NULL
0 0 0 0 0 0
0 0 1 1 1 1
0 1 NULL NULL NULL NULL
0 1 0 1 1 1
0 1 1 0 0 0
1 NULL NULL NULL NULL NULL
1 NULL 0 NULL NULL NULL
1 NULL 1 NULL NULL NULL
1 0 NULL NULL NULL NULL
1 0 0 1 1 1
1 0 1 0 0 0
1 1 NULL NULL NULL NULL
1 1 0 0 0 0
1 1 1 1 1 1
select count(*) from t1_30237_bool
where ((A XOR B) XOR C) != (A XOR (B XOR C));
count(*)
0
Testing that AND is associative
select A, B, C, (A AND B) AND C, A AND (B AND C), A AND B AND C
from t1_30237_bool order by A, B, C;
A B C (A AND B) AND C A AND (B AND C) A AND B AND C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 0 0 0
NULL NULL 1 NULL NULL NULL
NULL 0 NULL 0 0 0
NULL 0 0 0 0 0
NULL 0 1 0 0 0
NULL 1 NULL NULL NULL NULL
NULL 1 0 0 0 0
NULL 1 1 NULL NULL NULL
0 NULL NULL 0 0 0
0 NULL 0 0 0 0
0 NULL 1 0 0 0
0 0 NULL 0 0 0
0 0 0 0 0 0
0 0 1 0 0 0
0 1 NULL 0 0 0
0 1 0 0 0 0
0 1 1 0 0 0
1 NULL NULL NULL NULL NULL
1 NULL 0 0 0 0
1 NULL 1 NULL NULL NULL
1 0 NULL 0 0 0
1 0 0 0 0 0
1 0 1 0 0 0
1 1 NULL NULL NULL NULL
1 1 0 0 0 0
1 1 1 1 1 1
select count(*) from t1_30237_bool
where ((A AND B) AND C) != (A AND (B AND C));
count(*)
0
Testing that AND has precedence over OR
select A, B, C, (A OR B) AND C, A OR (B AND C), A OR B AND C
from t1_30237_bool order by A, B, C;
A B C (A OR B) AND C A OR (B AND C) A OR B AND C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 0 NULL NULL
NULL NULL 1 NULL NULL NULL
NULL 0 NULL NULL NULL NULL
NULL 0 0 0 NULL NULL
NULL 0 1 NULL NULL NULL
NULL 1 NULL NULL NULL NULL
NULL 1 0 0 NULL NULL
NULL 1 1 1 1 1
0 NULL NULL NULL NULL NULL
0 NULL 0 0 0 0
0 NULL 1 NULL NULL NULL
0 0 NULL 0 0 0
0 0 0 0 0 0
0 0 1 0 0 0
0 1 NULL NULL NULL NULL
0 1 0 0 0 0
0 1 1 1 1 1
1 NULL NULL NULL 1 1
1 NULL 0 0 1 1
1 NULL 1 1 1 1
1 0 NULL NULL 1 1
1 0 0 0 1 1
1 0 1 1 1 1
1 1 NULL NULL 1 1
1 1 0 0 1 1
1 1 1 1 1 1
select count(*) from t1_30237_bool
where (A OR (B AND C)) != (A OR B AND C);
count(*)
0
select A, B, C, (A AND B) OR C, A AND (B OR C), A AND B OR C
from t1_30237_bool order by A, B, C;
A B C (A AND B) OR C A AND (B OR C) A AND B OR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 1 NULL 1
NULL 0 NULL NULL NULL NULL
NULL 0 0 0 0 0
NULL 0 1 1 NULL 1
NULL 1 NULL NULL NULL NULL
NULL 1 0 NULL NULL NULL
NULL 1 1 1 NULL 1
0 NULL NULL NULL 0 NULL
0 NULL 0 0 0 0
0 NULL 1 1 0 1
0 0 NULL NULL 0 NULL
0 0 0 0 0 0
0 0 1 1 0 1
0 1 NULL NULL 0 NULL
0 1 0 0 0 0
0 1 1 1 0 1
1 NULL NULL NULL NULL NULL
1 NULL 0 NULL NULL NULL
1 NULL 1 1 1 1
1 0 NULL NULL NULL NULL
1 0 0 0 0 0
1 0 1 1 1 1
1 1 NULL 1 1 1
1 1 0 1 1 1
1 1 1 1 1 1
select count(*) from t1_30237_bool
where ((A AND B) OR C) != (A AND B OR C);
count(*)
0
Testing that AND has precedence over XOR
select A, B, C, (A XOR B) AND C, A XOR (B AND C), A XOR B AND C
from t1_30237_bool order by A, B, C;
A B C (A XOR B) AND C A XOR (B AND C) A XOR B AND C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 0 NULL NULL
NULL NULL 1 NULL NULL NULL
NULL 0 NULL NULL NULL NULL
NULL 0 0 0 NULL NULL
NULL 0 1 NULL NULL NULL
NULL 1 NULL NULL NULL NULL
NULL 1 0 0 NULL NULL
NULL 1 1 NULL NULL NULL
0 NULL NULL NULL NULL NULL
0 NULL 0 0 0 0
0 NULL 1 NULL NULL NULL
0 0 NULL 0 0 0
0 0 0 0 0 0
0 0 1 0 0 0
0 1 NULL NULL NULL NULL
0 1 0 0 0 0
0 1 1 1 1 1
1 NULL NULL NULL NULL NULL
1 NULL 0 0 1 1
1 NULL 1 NULL NULL NULL
1 0 NULL NULL 1 1
1 0 0 0 1 1
1 0 1 1 1 1
1 1 NULL 0 NULL NULL
1 1 0 0 1 1
1 1 1 0 0 0
select count(*) from t1_30237_bool
where (A XOR (B AND C)) != (A XOR B AND C);
count(*)
0
select A, B, C, (A AND B) XOR C, A AND (B XOR C), A AND B XOR C
from t1_30237_bool order by A, B, C;
A B C (A AND B) XOR C A AND (B XOR C) A AND B XOR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 NULL NULL NULL
NULL 0 NULL NULL NULL NULL
NULL 0 0 0 0 0
NULL 0 1 1 NULL 1
NULL 1 NULL NULL NULL NULL
NULL 1 0 NULL NULL NULL
NULL 1 1 NULL 0 NULL
0 NULL NULL NULL 0 NULL
0 NULL 0 0 0 0
0 NULL 1 1 0 1
0 0 NULL NULL 0 NULL
0 0 0 0 0 0
0 0 1 1 0 1
0 1 NULL NULL 0 NULL
0 1 0 0 0 0
0 1 1 1 0 1
1 NULL NULL NULL NULL NULL
1 NULL 0 NULL NULL NULL
1 NULL 1 NULL NULL NULL
1 0 NULL NULL NULL NULL
1 0 0 0 0 0
1 0 1 1 1 1
1 1 NULL NULL NULL NULL
1 1 0 1 1 1
1 1 1 0 0 0
select count(*) from t1_30237_bool
where ((A AND B) XOR C) != (A AND B XOR C);
count(*)
0
Testing that XOR has precedence over OR
select A, B, C, (A XOR B) OR C, A XOR (B OR C), A XOR B OR C
from t1_30237_bool order by A, B, C;
A B C (A XOR B) OR C A XOR (B OR C) A XOR B OR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 1 NULL 1
NULL 0 NULL NULL NULL NULL
NULL 0 0 NULL NULL NULL
NULL 0 1 1 NULL 1
NULL 1 NULL NULL NULL NULL
NULL 1 0 NULL NULL NULL
NULL 1 1 1 NULL 1
0 NULL NULL NULL NULL NULL
0 NULL 0 NULL NULL NULL
0 NULL 1 1 1 1
0 0 NULL NULL NULL NULL
0 0 0 0 0 0
0 0 1 1 1 1
0 1 NULL 1 1 1
0 1 0 1 1 1
0 1 1 1 1 1
1 NULL NULL NULL NULL NULL
1 NULL 0 NULL NULL NULL
1 NULL 1 1 0 1
1 0 NULL 1 NULL 1
1 0 0 1 1 1
1 0 1 1 0 1
1 1 NULL NULL 0 NULL
1 1 0 0 0 0
1 1 1 1 0 1
select count(*) from t1_30237_bool
where ((A XOR B) OR C) != (A XOR B OR C);
count(*)
0
select A, B, C, (A OR B) XOR C, A OR (B XOR C), A OR B XOR C
from t1_30237_bool order by A, B, C;
A B C (A OR B) XOR C A OR (B XOR C) A OR B XOR C
NULL NULL NULL NULL NULL NULL
NULL NULL 0 NULL NULL NULL
NULL NULL 1 NULL NULL NULL
NULL 0 NULL NULL NULL NULL
NULL 0 0 NULL NULL NULL
NULL 0 1 NULL 1 1
NULL 1 NULL NULL NULL NULL
NULL 1 0 1 1 1
NULL 1 1 0 NULL NULL
0 NULL NULL NULL NULL NULL
0 NULL 0 NULL NULL NULL
0 NULL 1 NULL NULL NULL
0 0 NULL NULL NULL NULL
0 0 0 0 0 0
0 0 1 1 1 1
0 1 NULL NULL NULL NULL
0 1 0 1 1 1
0 1 1 0 0 0
1 NULL NULL NULL 1 1
1 NULL 0 1 1 1
1 NULL 1 0 1 1
1 0 NULL NULL 1 1
1 0 0 1 1 1
1 0 1 0 1 1
1 1 NULL NULL 1 1
1 1 0 1 1 1
1 1 1 0 1 1
select count(*) from t1_30237_bool
where (A OR (B XOR C)) != (A OR B XOR C);
count(*)
0
drop table t1_30237_bool;
mysql-test/t/parser_precedence.test 0 → 100644
View file @ fb1be0f1
--disable_warnings
drop table if exists t1_30237_bool;
--enable_warnings
create table t1_30237_bool(A boolean, B boolean, C boolean);
insert into t1_30237_bool values
(FALSE, FALSE, FALSE),
(FALSE, FALSE, NULL),
(FALSE, FALSE, TRUE),
(FALSE, NULL, FALSE),
(FALSE, NULL, NULL),
(FALSE, NULL, TRUE),
(FALSE, TRUE, FALSE),
(FALSE, TRUE, NULL),
(FALSE, TRUE, TRUE),
(NULL, FALSE, FALSE),
(NULL, FALSE, NULL),
(NULL, FALSE, TRUE),
(NULL, NULL, FALSE),
(NULL, NULL, NULL),
(NULL, NULL, TRUE),
(NULL, TRUE, FALSE),
(NULL, TRUE, NULL),
(NULL, TRUE, TRUE),
(TRUE, FALSE, FALSE),
(TRUE, FALSE, NULL),
(TRUE, FALSE, TRUE),
(TRUE, NULL, FALSE),
(TRUE, NULL, NULL),
(TRUE, NULL, TRUE),
(TRUE, TRUE, FALSE),
(TRUE, TRUE, NULL),
(TRUE, TRUE, TRUE) ;
--echo Testing OR, XOR, AND
select A, B, A OR B, A XOR B, A AND B
from t1_30237_bool where C is null order by A, B;
--echo Testing that OR is associative
select A, B, C, (A OR B) OR C, A OR (B OR C), A OR B OR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A OR B) OR C) != (A OR (B OR C));
--echo Testing that XOR is associative
select A, B, C, (A XOR B) XOR C, A XOR (B XOR C), A XOR B XOR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A XOR B) XOR C) != (A XOR (B XOR C));
--echo Testing that AND is associative
select A, B, C, (A AND B) AND C, A AND (B AND C), A AND B AND C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A AND B) AND C) != (A AND (B AND C));
--echo Testing that AND has precedence over OR
select A, B, C, (A OR B) AND C, A OR (B AND C), A OR B AND C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where (A OR (B AND C)) != (A OR B AND C);
select A, B, C, (A AND B) OR C, A AND (B OR C), A AND B OR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A AND B) OR C) != (A AND B OR C);
--echo Testing that AND has precedence over XOR
select A, B, C, (A XOR B) AND C, A XOR (B AND C), A XOR B AND C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where (A XOR (B AND C)) != (A XOR B AND C);
select A, B, C, (A AND B) XOR C, A AND (B XOR C), A AND B XOR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A AND B) XOR C) != (A AND B XOR C);
--echo Testing that XOR has precedence over OR
select A, B, C, (A XOR B) OR C, A XOR (B OR C), A XOR B OR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where ((A XOR B) OR C) != (A XOR B OR C);
select A, B, C, (A OR B) XOR C, A OR (B XOR C), A OR B XOR C
from t1_30237_bool order by A, B, C;
select count(*) from t1_30237_bool
where (A OR (B XOR C)) != (A OR B XOR C);
drop table t1_30237_bool;
sql/item_cmpfunc.h
View file @ fb1be0f1
......@@ -1361,6 +1361,7 @@ public:
Item_cond(List<Item> &nlist)
:Item_bool_func(), list(nlist), abort_on_null(0) {}
bool add(Item *item) { return list.push_back(item); }
bool add_at_head(Item *item) { return list.push_front(item); }
void add_at_head(List<Item> *nlist) { list.prepand(nlist); }
bool fix_fields(THD *, Item **ref);
......@@ -1554,6 +1555,15 @@ public:
Item *neg_transformer(THD *thd);
};
inline bool is_cond_and(Item *item)
{
if (item->type() != Item::COND_ITEM)
return FALSE;
Item_cond *cond_item= (Item_cond*) item;
return (cond_item->functype() == Item_func::COND_AND_FUNC);
}
class Item_cond_or :public Item_cond
{
public:
......@@ -1575,6 +1585,14 @@ public:
Item *neg_transformer(THD *thd);
};
inline bool is_cond_or(Item *item)
{
if (item->type() != Item::COND_ITEM)
return FALSE;
Item_cond *cond_item= (Item_cond*) item;
return (cond_item->functype() == Item_func::COND_OR_FUNC);
}
/*
XOR is Item_cond, not an Item_int_func because we could like to
......
sql/sql_yacc.yy
View file @ fb1be0f1
......@@ -458,10 +458,10 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
%pure_parser /* We have threads */
/*
Currently there is 251 shift/reduce conflict. We should not introduce
new conflicts any more.
Currently there are 245 shift/reduce conflicts.
We should not introduce new conflicts any more.
*/
%expect 251
%expect 245
%token END_OF_INPUT
......@@ -1011,7 +1011,8 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
/* A dummy token to force the priority of table_ref production in a join. */
%left TABLE_REF_PRIORITY
%left SET_VAR
%left OR_OR_SYM OR_SYM OR2_SYM XOR
%left OR_OR_SYM OR_SYM OR2_SYM
%left XOR
%left AND_SYM AND_AND_SYM
%left BETWEEN_SYM CASE_SYM WHEN_SYM THEN_SYM ELSE
%left EQ EQUAL_SYM GE GT_SYM LE LT NE IS LIKE REGEXP IN_SYM
......@@ -1024,6 +1025,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
%left NEG '~'
%right NOT_SYM NOT2_SYM
%right BINARY COLLATE_SYM
%left INTERVAL_SYM
%type <lex_str>
IDENT IDENT_QUOTED TEXT_STRING DECIMAL_NUM FLOAT_NUM NUM LONG_NUM HEX_NUM
......@@ -1066,7 +1068,8 @@ bool my_yyoverflow(short **a, YYSTYPE **b, ulong *yystacksize);
%type <item>
literal text_literal insert_ident order_ident
simple_ident select_item2 expr opt_expr opt_else sum_expr in_sum_expr
variable variable_aux bool_term bool_factor bool_test bool_pri
variable variable_aux bool_factor
bool_test bool_pri
predicate bit_expr bit_term bit_factor value_expr term factor
table_wild simple_expr udf_expr
expr_or_default set_expr_or_default interval_expr
......@@ -4464,53 +4467,103 @@ optional_braces:
| '(' ')' {};
/* all possible expressions */
expr:
bool_term { Select->expr_list.push_front(new List<Item>); }
bool_or_expr
expr:
bool_factor
| expr or expr %prec OR_SYM
{
List<Item> *list= Select->expr_list.pop();
if (list->elements)
/*
Design notes:
Do not use a manually maintained stack like thd->lex->xxx_list,
but use the internal bison stack ($$, $1 and $3) instead.
Using the bison stack is:
- more robust to changes in the grammar,
- guaranteed to be in sync with the parser state,
- better for performances (no memory allocation).
*/
Item_cond_or *item1;
Item_cond_or *item3;
if (is_cond_or($1))
{
list->push_front($1);
$$= new Item_cond_or(*list);
/* optimize construction of logical OR to reduce
amount of objects for complex expressions */
item1= (Item_cond_or*) $1;
if (is_cond_or($3))
{
item3= (Item_cond_or*) $3;
/*
(X1 OR X2) OR (Y1 OR Y2) ==> OR (X1, X2, Y1, Y2)
*/
item3->add_at_head(item1->argument_list());
$$ = $3;
}
else
{
/*
(X1 OR X2) OR Y ==> OR (X1, X2, Y)
*/
item1->add($3);
$$ = $1;
}
}
else if (is_cond_or($3))
{
item3= (Item_cond_or*) $3;
/*
X OR (Y1 OR Y2) ==> OR (X, Y1, Y2)
*/
item3->add_at_head($1);
$$ = $3;
}
else
$$= $1;
delete list;
{
/* X OR Y */
$$ = new (YYTHD->mem_root) Item_cond_or($1, $3);
}
}
;
bool_or_expr:
/* empty */
| bool_or_expr or bool_term
{ Select->expr_list.head()->push_back($3); }
;
bool_term:
bool_term XOR bool_term { $$= new Item_cond_xor($1,$3); }
| bool_factor { Select->expr_list.push_front(new List<Item>); }
bool_and_expr
| expr XOR expr %prec XOR
{
/* XOR is a proprietary extension */
$$ = new (YYTHD->mem_root) Item_cond_xor($1, $3);
}
| expr and expr %prec AND_SYM
{
List<Item> *list= Select->expr_list.pop();
if (list->elements)
/* See comments in rule expr: expr or expr */
Item_cond_and *item1;
Item_cond_and *item3;
if (is_cond_and($1))
{
list->push_front($1);
$$= new Item_cond_and(*list);
/* optimize construction of logical AND to reduce
amount of objects for complex expressions */
item1= (Item_cond_and*) $1;
if (is_cond_and($3))
{
item3= (Item_cond_and*) $3;
/*
(X1 AND X2) AND (Y1 AND Y2) ==> AND (X1, X2, Y1, Y2)
*/
item3->add_at_head(item1->argument_list());
$$ = $3;
}
else
{
/*
(X1 AND X2) AND Y ==> AND (X1, X2, Y)
*/
item1->add($3);
$$ = $1;
}
}
else if (is_cond_and($3))
{
item3= (Item_cond_and*) $3;
/*
X AND (Y1 AND Y2) ==> AND (X, Y1, Y2)
*/
item3->add_at_head($1);
$$ = $3;
}
else
$$= $1;
delete list;
{
/* X AND Y */
$$ = new (YYTHD->mem_root) Item_cond_and($1, $3);
}
}
;
bool_and_expr:
/* empty */
| bool_and_expr and bool_factor
{ Select->expr_list.head()->push_back($3); }
;
bool_factor:
......@@ -4648,7 +4701,8 @@ all_or_any: ALL { $$ = 1; }
;
interval_expr:
INTERVAL_SYM expr { $$=$2; }
INTERVAL_SYM expr %prec INTERVAL_SYM
{ $$=$2; }
;
simple_expr:
......
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