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Message #10127
Please review MDEV-11365 Split the data type and attribute related code in Item_sum_hybrid::fix_fields into Type_handler::Item_sum_hybrid_fix_length_and_dec()
Hello Sanja,
Please review MDEV-11365.
Thanks!
commit aa55bda2506daa56adbeca5351502a6a1b0934af
Author: Alexander Barkov <bar@xxxxxxxxxxx>
Date: Mon Nov 28 10:21:01 2016 +0400
MDEV-11365 Split the data type and attribute related code in Item_sum_hybrid::fix_fields into Type_handler::Item_sum_hybrid_fix_length_and_dec()
This patch:
- Implements the task according to the description
- Adds a new class Type_handler_numeric as a common parent
for Type_handler_real_result, Type_handler_int_result,
Type_handler_decimal_result, to share the common code
between numeric data type handlers.
- Removes the dedundant call for collation.set(item->collation) in
Item_sum_hybrid::setup_hybrid(), because setup_hybrid() is called
either after fix_length_and_dec() or afte ther constructor
Item_sum_hybrid(THD *thd, Item_sum_hybrid *item),
so the collation is already properly set in all cases.
diff --git a/sql/item_sum.cc b/sql/item_sum.cc
index 9ffb056..879115d 100644
--- a/sql/item_sum.cc
+++ b/sql/item_sum.cc
@@ -1126,36 +1126,11 @@ Item_sum_hybrid::fix_fields(THD *thd, Item **ref)
if ((!item->fixed && item->fix_fields(thd, args)) ||
(item= args[0])->check_cols(1))
return TRUE;
- Type_std_attributes::set(args[0]);
with_subselect= args[0]->with_subselect;
- Item *item2= item->real_item();
- if (item2->type() == Item::FIELD_ITEM)
- set_handler_by_field_type(((Item_field*) item2)->field->type());
- else if (item->cmp_type() == TIME_RESULT)
- set_handler_by_field_type(item2->field_type());
- else
- set_handler_by_result_type(item2->result_type(),
- max_length, collation.collation);
-
- switch (Item_sum_hybrid::result_type()) {
- case INT_RESULT:
- case DECIMAL_RESULT:
- case STRING_RESULT:
- break;
- case REAL_RESULT:
- max_length= float_length(decimals);
- break;
- case ROW_RESULT:
- case TIME_RESULT:
- DBUG_ASSERT(0);
- };
+ fix_length_and_dec();
setup_hybrid(thd, args[0], NULL);
- /* MIN/MAX can return NULL for empty set indepedent of the used column */
- maybe_null= 1;
result_field=0;
- null_value=1;
- fix_length_and_dec();
if (check_sum_func(thd, ref))
return TRUE;
@@ -1166,6 +1141,14 @@ Item_sum_hybrid::fix_fields(THD *thd, Item **ref)
}
+void Item_sum_hybrid::fix_length_and_dec()
+{
+ DBUG_ASSERT(args[0]->field_type() == args[0]->real_item()->field_type());
+ DBUG_ASSERT(args[0]->result_type() == args[0]->real_item()->result_type());
+ (void) args[0]->type_handler()->Item_sum_hybrid_fix_length_and_dec(this);
+}
+
+
/**
MIN/MAX function setup.
@@ -1201,7 +1184,6 @@ void Item_sum_hybrid::setup_hybrid(THD *thd, Item *item, Item *value_arg)
cmp= new Arg_comparator();
if (cmp)
cmp->set_cmp_func(this, (Item**)&arg_cache, (Item**)&value, FALSE);
- collation.set(item->collation);
}
diff --git a/sql/item_sum.h b/sql/item_sum.h
index 76cc983..59d7587 100644
--- a/sql/item_sum.h
+++ b/sql/item_sum.h
@@ -1006,6 +1006,7 @@ class Item_sum_hybrid :public Item_sum, public Type_handler_hybrid_field_type
cmp_sign(item->cmp_sign), was_values(item->was_values)
{ }
bool fix_fields(THD *, Item **);
+ void fix_length_and_dec();
void setup_hybrid(THD *thd, Item *item, Item *value_arg);
void clear();
double val_real();
diff --git a/sql/sql_type.cc b/sql/sql_type.cc
index f94e18d..12fd73d 100644
--- a/sql/sql_type.cc
+++ b/sql/sql_type.cc
@@ -761,3 +761,101 @@ Type_handler_temporal_result::Item_get_cache(THD *thd, const Item *item) const
/*************************************************************************/
+/**
+ MAX/MIN for the traditional numeric types preserve the exact data type
+ from Fields, but do not preserve the exact type from Items:
+ MAX(float_field) -> FLOAT
+ MAX(smallint_field) -> LONGLONG
+ MAX(COALESCE(float_field)) -> DOUBLE
+ MAX(COALESCE(smallint_field)) -> LONGLONG
+ QQ: Items should probably be fixed to preserve the exact type.
+*/
+bool Type_handler_numeric::
+ Item_sum_hybrid_fix_length_and_dec_numeric(Item_sum_hybrid *func,
+ const Type_handler *handler)
+ const
+{
+ Item *item= func->arguments()[0];
+ Item *item2= item->real_item();
+ func->Type_std_attributes::set(item);
+ /* MIN/MAX can return NULL for empty set indepedent of the used column */
+ func->maybe_null= func->null_value= true;
+ if (item2->type() == Item::FIELD_ITEM)
+ func->set_handler_by_field_type(item2->field_type());
+ else
+ func->set_handler(handler);
+ return false;
+}
+
+
+bool Type_handler_int_result::
+ Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+{
+ return Item_sum_hybrid_fix_length_and_dec_numeric(func,
+ &type_handler_longlong);
+}
+
+
+bool Type_handler_real_result::
+ Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+{
+ (void) Item_sum_hybrid_fix_length_and_dec_numeric(func,
+ &type_handler_double);
+ func->max_length= func->float_length(func->decimals);
+ return false;
+}
+
+
+bool Type_handler_decimal_result::
+ Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+{
+ return Item_sum_hybrid_fix_length_and_dec_numeric(func,
+ &type_handler_newdecimal);
+}
+
+
+/**
+ MAX(str_field) converts ENUM/SET to CHAR, and preserve all other types
+ for Fields.
+ QQ: This works differently from UNION, which preserve the exact data
+ type for ENUM/SET if the joined ENUM/SET fields are equally defined.
+ Perhaps should be fixed.
+ MAX(str_item) chooses the best suitable string type.
+*/
+bool Type_handler_string_result::
+ Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+{
+ Item *item= func->arguments()[0];
+ Item *item2= item->real_item();
+ func->Type_std_attributes::set(item);
+ func->maybe_null= func->null_value= true;
+ if (item2->type() == Item::FIELD_ITEM)
+ {
+ // Fields: convert ENUM/SET to CHAR, preserve the type otherwise.
+ func->set_handler_by_field_type(item->field_type());
+ }
+ else
+ {
+ // Items: choose VARCHAR/BLOB/MEDIUMBLOB/LONGBLOB, depending on length.
+ func->set_handler(type_handler_varchar.
+ type_handler_adjusted_to_max_octet_length(func->max_length,
+ func->collation.collation));
+ }
+ return false;
+}
+
+
+/**
+ Traditional temporal types always preserve the type of the argument.
+*/
+bool Type_handler_temporal_result::
+ Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+{
+ Item *item= func->arguments()[0];
+ func->Type_std_attributes::set(item);
+ func->maybe_null= func->null_value= true;
+ func->set_handler(item->type_handler());
+ return false;
+}
+
+/*************************************************************************/
diff --git a/sql/sql_type.h b/sql/sql_type.h
index 87cd5c4..ef85f3d 100644
--- a/sql/sql_type.h
+++ b/sql/sql_type.h
@@ -26,6 +26,7 @@
class Field;
class Item;
class Item_cache;
+class Item_sum_hybrid;
class Type_std_attributes;
class Sort_param;
class Arg_comparator;
@@ -289,6 +290,7 @@ class Type_handler
bool no_conversions) const= 0;
virtual Item_cache *Item_get_cache(THD *thd, const Item *item) const= 0;
virtual bool set_comparator_func(Arg_comparator *cmp) const= 0;
+ virtual bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *) const= 0;
};
@@ -342,12 +344,31 @@ class Type_handler_row: public Type_handler
}
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const
+ {
+ DBUG_ASSERT(0);
+ return true;
+ }
+};
+
+
+/*
+ A common parent class for numeric data type handlers
+*/
+class Type_handler_numeric: public Type_handler
+{
+protected:
+ bool Item_sum_hybrid_fix_length_and_dec_numeric(Item_sum_hybrid *func,
+ const Type_handler *handler)
+ const;
+public:
+ virtual ~Type_handler_numeric() { }
};
/*** Abstract classes for every XXX_RESULT */
-class Type_handler_real_result: public Type_handler
+class Type_handler_real_result: public Type_handler_numeric
{
public:
Item_result result_type() const { return REAL_RESULT; }
@@ -361,10 +382,11 @@ class Type_handler_real_result: public Type_handler
int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
};
-class Type_handler_decimal_result: public Type_handler
+class Type_handler_decimal_result: public Type_handler_numeric
{
public:
Item_result result_type() const { return DECIMAL_RESULT; }
@@ -379,10 +401,11 @@ class Type_handler_decimal_result: public Type_handler
int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
};
-class Type_handler_int_result: public Type_handler
+class Type_handler_int_result: public Type_handler_numeric
{
public:
Item_result result_type() const { return INT_RESULT; }
@@ -397,6 +420,7 @@ class Type_handler_int_result: public Type_handler
int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
};
@@ -413,6 +437,7 @@ class Type_handler_temporal_result: public Type_handler
SORT_FIELD_ATTR *attr) const;
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
};
@@ -433,6 +458,7 @@ class Type_handler_string_result: public Type_handler
int Item_save_in_field(Item *item, Field *field, bool no_conversions) const;
Item_cache *Item_get_cache(THD *thd, const Item *item) const;
bool set_comparator_func(Arg_comparator *cmp) const;
+ bool Item_sum_hybrid_fix_length_and_dec(Item_sum_hybrid *func) const;
};