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optimize constant default expressions

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to be calculated at the CREATE TABLE time and stored in
the default row image.
This commit is contained in:
Sergei Golubchik
2016-07-23 16:55:52 +02:00
parent 4070d55735
commit 12d2c4fcd0
7 changed files with 141 additions and 118 deletions
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3
mysql-test/r/default.result
View File

@ -409,7 +409,6 @@ create or replace table t1 (a int not null, b int default (a+1));
create or replace table t1 (a int default a);
ERROR 01000: Expression for field `a` is refering to uninitialized field `a`
create or replace table t1 (a int default b, b int default (1+1));
ERROR 01000: Expression for field `a` is refering to uninitialized field `b`
create or replace table t1 (a int default 1, b int as (c), c int as (a+1));
ERROR 01000: Expression for field `b` is refering to uninitialized field `c`
CREATE TABLE t1 (a INT DEFAULT (DEFAULT(a)));
@ -3035,7 +3034,7 @@ t1 CREATE TABLE `t1` (
`a` char(2) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci DEFAULT concat('A')
) ENGINE=MyISAM DEFAULT CHARSET=latin1
DROP TABLE t1;
create table t1 (a int default 1, b int default (1+1), c int);
create table t1 (a int default 1, b int default (rand()*0+2), c int);
insert t1 (c) values (a);
insert t1 (c) values (b);
select * from t1;

3
mysql-test/t/default.test
View File

@ -295,7 +295,6 @@ create or replace table t1 (a int not null, b int default (a+1));
--error ER_EXPRESSION_REFERS_TO_UNINIT_FIELD
create or replace table t1 (a int default a);
--error ER_EXPRESSION_REFERS_TO_UNINIT_FIELD
create or replace table t1 (a int default b, b int default (1+1));
--error ER_EXPRESSION_REFERS_TO_UNINIT_FIELD
create or replace table t1 (a int default 1, b int as (c), c int as (a+1));
@ -1810,7 +1809,7 @@ DROP TABLE t1;
#
# Order of evaluation:
#
create table t1 (a int default 1, b int default (1+1), c int);
create table t1 (a int default 1, b int default (rand()*0+2), c int);
insert t1 (c) values (a);
insert t1 (c) values (b);
select * from t1;

6
sql/field.h
View File

@ -574,7 +574,11 @@ inline bool is_temporal_type_with_time(enum_field_types type)
}
}
/* Bits for type of vcol expression */
/*
Flags for Virtual_column_info. If none is set, the expression must be
a constant with no side-effects, so it's calculated at CREATE TABLE time,
stored in table->record[2], and not recalculated for every statement.
*/
#define VCOL_FIELD_REF 1
#define VCOL_NON_DETERMINISTIC 2
#define VCOL_SESSION_FUNC 4 /* uses session data, e.g. USER or DAYNAME */

6
sql/item.cc
View File

@ -956,8 +956,8 @@ bool Item_field::check_field_expression_processor(void *arg)
{
if (field->flags & NO_DEFAULT_VALUE_FLAG)
return 0;
if ((field->default_value || field->has_insert_default_function() ||
field->vcol_info))
if ((field->default_value && field->default_value->flags)
|| field->has_insert_default_function() || field->vcol_info)
{
Field *org_field= (Field*) arg;
if (field == org_field ||
@ -8232,7 +8232,7 @@ bool Item_default_value::fix_fields(THD *thd, Item **items)
set_field(def_field);
if (field->default_value)
{
if (field->default_value->expr_item) // it's NULL during CREATE TABLE
if (thd->mark_used_columns != MARK_COLUMNS_NONE)
field->default_value->expr_item->walk(&Item::register_field_in_read_map, 1, 0);
IF_DBUG(def_field->is_stat_field=1,); // a hack to fool ASSERT_COLUMN_MARKED_FOR_WRITE_OR_COMPUTED
}

190
sql/sql_table.cc
View File

@ -3255,35 +3255,6 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
!(sql_field->charset= find_bin_collation(sql_field->charset)))
DBUG_RETURN(TRUE);
/*
Convert the default value from client character
set into the column character set if necessary.
We can only do this for constants as we have not yet run fix_fields.
*/
if (sql_field->default_value &&
sql_field->default_value->expr_item->basic_const_item() &&
save_cs != sql_field->default_value->expr_item->collation.collation &&
(sql_field->sql_type == MYSQL_TYPE_VAR_STRING ||
sql_field->sql_type == MYSQL_TYPE_STRING ||
sql_field->sql_type == MYSQL_TYPE_SET ||
sql_field->sql_type == MYSQL_TYPE_TINY_BLOB ||
sql_field->sql_type == MYSQL_TYPE_MEDIUM_BLOB ||
sql_field->sql_type == MYSQL_TYPE_LONG_BLOB ||
sql_field->sql_type == MYSQL_TYPE_BLOB ||
sql_field->sql_type == MYSQL_TYPE_ENUM))
{
Item *item;
if (!(item= sql_field->default_value->expr_item->
safe_charset_converter(thd, save_cs)))
{
/* Could not convert */
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
/* Fix for prepare statement */
thd->change_item_tree(&sql_field->default_value->expr_item, item);
}
if (sql_field->sql_type == MYSQL_TYPE_SET ||
sql_field->sql_type == MYSQL_TYPE_ENUM)
{
@ -3349,37 +3320,6 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
if (sql_field->sql_type == MYSQL_TYPE_SET)
{
uint32 field_length;
if (sql_field->default_value &&
sql_field->default_value->expr_item->basic_const_item())
{
char *not_used;
uint not_used2;
bool not_found= 0;
String str, *def= sql_field->default_value->expr_item->val_str(&str);
if (def == NULL) /* SQL "NULL" maps to NULL */
{
if ((sql_field->flags & NOT_NULL_FLAG) != 0)
{
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
/* else, NULL is an allowed value */
(void) find_set(interval, NULL, 0,
cs, &not_used, &not_used2, &not_found);
}
else /* not NULL */
{
(void) find_set(interval, def->ptr(), def->length(),
cs, &not_used, &not_used2, &not_found);
}
if (not_found)
{
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
}
calculate_interval_lengths(cs, interval, &dummy, &field_length);
sql_field->length= field_length + (interval->count - 1);
}
@ -3387,30 +3327,6 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
{
uint32 field_length;
DBUG_ASSERT(sql_field->sql_type == MYSQL_TYPE_ENUM);
if (sql_field->default_value &&
sql_field->default_value->expr_item->basic_const_item())
{
String str, *def= sql_field->default_value->expr_item->val_str(&str);
if (def == NULL) /* SQL "NULL" maps to NULL */
{
if ((sql_field->flags & NOT_NULL_FLAG) != 0)
{
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
/* else, the defaults yield the correct length for NULLs. */
}
else /* not NULL */
{
def->length(cs->cset->lengthsp(cs, def->ptr(), def->length()));
if (find_type2(interval, def->ptr(), def->length(), cs) == 0) /* not found */
{
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
}
}
calculate_interval_lengths(cs, interval, &field_length, &dummy);
sql_field->length= field_length;
}
@ -3430,6 +3346,112 @@ mysql_prepare_create_table(THD *thd, HA_CREATE_INFO *create_info,
if (prepare_blob_field(thd, sql_field))
DBUG_RETURN(TRUE);
if (sql_field->default_value)
{
Virtual_column_info *def= sql_field->default_value;
if (!sql_field->has_default_expression())
def->expr_str= null_lex_str;
if (!def->expr_item->basic_const_item() && !def->flags)
{
Item *expr= def->expr_item;
int err= !expr->fixed && // may be already fixed if ALTER TABLE
expr->fix_fields(thd, &expr);
if (!err)
{
if (expr->result_type() == REAL_RESULT)
{ // don't convert floats to string and back, it can be lossy
double res= expr->val_real();
if (expr->null_value)
expr= new (thd->mem_root) Item_null(thd);
else
expr= new (thd->mem_root) Item_float(thd, res, expr->decimals);
}
else
{
StringBuffer<MAX_FIELD_WIDTH> buf;
String *res= expr->val_str(&buf);
if (expr->null_value)
expr= new (thd->mem_root) Item_null(thd);
else
{
char *str= (char*) thd->strmake(res->ptr(), res->length());
expr= new (thd->mem_root) Item_string(thd, str, res->length(), res->charset());
}
}
thd->change_item_tree(&def->expr_item, expr);
}
}
}
/*
Convert the default value from client character
set into the column character set if necessary.
We can only do this for constants as we have not yet run fix_fields.
*/
if (sql_field->default_value &&
sql_field->default_value->expr_item->basic_const_item() &&
save_cs != sql_field->default_value->expr_item->collation.collation &&
(sql_field->sql_type == MYSQL_TYPE_VAR_STRING ||
sql_field->sql_type == MYSQL_TYPE_STRING ||
sql_field->sql_type == MYSQL_TYPE_SET ||
sql_field->sql_type == MYSQL_TYPE_TINY_BLOB ||
sql_field->sql_type == MYSQL_TYPE_MEDIUM_BLOB ||
sql_field->sql_type == MYSQL_TYPE_LONG_BLOB ||
sql_field->sql_type == MYSQL_TYPE_BLOB ||
sql_field->sql_type == MYSQL_TYPE_ENUM))
{
Item *item;
if (!(item= sql_field->default_value->expr_item->
safe_charset_converter(thd, save_cs)))
{
/* Could not convert */
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
/* Fix for prepare statement */
thd->change_item_tree(&sql_field->default_value->expr_item, item);
}
if (sql_field->default_value &&
sql_field->default_value->expr_item->basic_const_item() &&
(sql_field->sql_type == MYSQL_TYPE_SET ||
sql_field->sql_type == MYSQL_TYPE_ENUM))
{
StringBuffer<MAX_FIELD_WIDTH> str;
String *def= sql_field->default_value->expr_item->val_str(&str);
bool not_found;
if (def == NULL) /* SQL "NULL" maps to NULL */
{
not_found= sql_field->flags & NOT_NULL_FLAG;
}
else
{
not_found= false;
if (sql_field->sql_type == MYSQL_TYPE_SET)
{
char *not_used;
uint not_used2;
find_set(sql_field->interval, def->ptr(), def->length(),
sql_field->charset, &not_used, &not_used2, &not_found);
}
else /* MYSQL_TYPE_ENUM */
{
def->length(sql_field->charset->cset->lengthsp(sql_field->charset,
def->ptr(), def->length()));
not_found= !find_type2(sql_field->interval, def->ptr(),
def->length(), sql_field->charset);
}
}
if (not_found)
{
my_error(ER_INVALID_DEFAULT, MYF(0), sql_field->field_name);
DBUG_RETURN(TRUE);
}
}
if (!(sql_field->flags & NOT_NULL_FLAG))
null_fields++;

47
sql/table.cc
View File

@ -2593,13 +2593,6 @@ static bool fix_and_check_vcol_expr(THD *thd, TABLE *table, Field *field,
DBUG_RETURN(1);
}
/* Check that we are not refering to any not yet initialized fields */
if (field)
{
if (func_expr->walk(&Item::check_field_expression_processor, 0, field))
DBUG_RETURN(1);
}
/*
Walk through the Item tree checking if all items are valid
to be part of the virtual column
@ -2777,6 +2770,14 @@ end:
DBUG_RETURN(vcol_info);
}
static bool check_vcol_forward_refs(Field *field, Virtual_column_info *vcol)
{
bool res= vcol &&
vcol->expr_item->walk(&Item::check_field_expression_processor, 0,
field);
return res;
}
/*
Read data from a binary .frm file from MySQL 3.23 - 5.0 into TABLE_SHARE
*/
@ -3041,22 +3042,6 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
goto err;
}
field->default_value= vcol;
if (is_create_table && !vcol->flags)
{
enum_check_fields old_count_cuted_fields= thd->count_cuted_fields;
thd->count_cuted_fields= CHECK_FIELD_WARN; // To find wrong default values
my_ptrdiff_t off= share->default_values - outparam->record[0];
field->move_field_offset(off);
int res= vcol->expr_item->save_in_field(field, 1);
field->move_field_offset(-off);
thd->count_cuted_fields= old_count_cuted_fields;
if (res != 0 && res != 3)
{
my_error(ER_INVALID_DEFAULT, MYF(0), field->field_name);
error= OPEN_FRM_CORRUPTED;
goto err;
}
}
*(dfield_ptr++)= *field_ptr;
}
else
@ -3068,6 +3053,19 @@ enum open_frm_error open_table_from_share(THD *thd, TABLE_SHARE *share,
*vfield_ptr= 0; // End marker
*dfield_ptr= 0; // End marker
/* Check that expressions aren't refering to not yet initialized fields */
for (field_ptr= outparam->field; *field_ptr; field_ptr++)
{
Field *field= *field_ptr;
if (check_vcol_forward_refs(field, field->vcol_info) ||
check_vcol_forward_refs(field, field->check_constraint) ||
check_vcol_forward_refs(field, field->default_value))
{
error= OPEN_FRM_CORRUPTED;
goto err;
}
}
/* Update to use trigger fields */
switch_defaults_to_nullable_trigger_fields(outparam);
@ -7316,7 +7314,8 @@ int TABLE::update_default_fields(bool update_command, bool ignore_errors)
{
if (!update_command)
{
if (field->default_value)
if (field->default_value &&
(field->default_value->flags || field->flags & BLOB_FLAG))
res|= (field->default_value->expr_item->save_in_field(field, 0) < 0);
else
res|= field->evaluate_insert_default_function();

4
sql/unireg.cc
View File

@ -634,7 +634,7 @@ static bool pack_header(THD *thd, uchar *forminfo,
if (add_expr_length(thd, &field->vcol_info, &expression_length))
DBUG_RETURN(1);
if (field->has_default_expression())
if (field->default_value && field->default_value->expr_str.length)
if (add_expr_length(thd, &field->default_value, &expression_length))
DBUG_RETURN(1);
if (add_expr_length(thd, &field->check_constraint, &expression_length))
@ -983,7 +983,7 @@ static bool pack_fields(uchar **buff_arg, List<Create_field> &create_fields,
if (field->vcol_info)
pack_expression(&buff, field->vcol_info, field_nr,
field->vcol_info->stored_in_db ? 1 : 0);
if (field->has_default_expression())
if (field->default_value && field->default_value->expr_str.length)
pack_expression(&buff, field->default_value, field_nr, 2);
if (field->check_constraint)
pack_expression(&buff, field->check_constraint, field_nr, 3);