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#ifdef USE_PRAGMA_IMPLEMENTATION
#pragma implementation // gcc: Class implementation
#endif
#include "mariadb.h"
#include "sql_priv.h"
#include <m_ctype.h>
#include "sql_partition.h"
#include "sql_select.h"
#include "opt_trace.h"
/*
@brief
Check if passed item is "UCASE(table.colX)" where colX is either covered
by some index or is a part of partition expression.
@return
Argument of the UCASE if passed item matches
NULL otherwise.
*/
static Item* is_upper_key_col(Item *item)
{
Item_func_ucase *item_func;
if ((item_func= dynamic_cast<Item_func_ucase*>(item)))
{
Item *arg= item_func->arguments()[0];
Item *arg_real= arg->real_item();
if (arg_real->type() == Item::FIELD_ITEM)
{
if (dynamic_cast<const Type_handler_longstr*>(arg_real->type_handler()))
{
Field *field= ((Item_field*)arg_real)->field;
bool appl= (field->flags & PART_KEY_FLAG);
#ifdef WITH_PARTITION_STORAGE_ENGINE
partition_info *part_info;
if (!appl && ((part_info= field->table->part_info)))
{
appl= bitmap_is_set(&part_info->full_part_field_set,
field->field_index);
}
#endif
if (appl)
{
/*
Make sure COERCIBILITY(UPPER(col))=COERCIBILITY(col)
*/
DBUG_ASSERT(arg->collation.derivation ==
item_func->collation.derivation);
/* Return arg, not arg_real. Do not walk into Item_ref objects */
return arg;
}
}
}
}
return nullptr;
}
static void trace_upper_removal_rewrite(THD *thd, Item *old_item, Item *new_item)
{
Json_writer_object trace_wrapper(thd);
Json_writer_object obj(thd, "sargable_casefold_removal");
obj.add("before", old_item)
.add("after", new_item);
}
/*
@brief
Rewrite UPPER(key_varchar_col) = expr into key_varchar_col=expr
@detail
UPPER() may occur on both sides of the equality.
UCASE() is a synonym of UPPER() so we handle it, too.
*/
Item* Item_func_eq::varchar_upper_cmp_transformer(THD *thd, uchar *arg)
{
if (cmp.compare_type() == STRING_RESULT &&
cmp.compare_collation()->state & MY_CS_UPPER_EQUAL_AS_EQUAL)
{
Item *arg0= arguments()[0];
Item *arg1= arguments()[1];
bool do_rewrite= false;
Item *tmp;
// Try rewriting the left argument
if ((tmp= is_upper_key_col(arguments()[0])))
{
arg0= tmp;
do_rewrite= true;
}
// Try rewriting the right argument
if ((tmp= is_upper_key_col(arguments()[1])))
{
arg1=tmp;
do_rewrite= true;
}
if (do_rewrite)
{
Item *res= new (thd->mem_root) Item_func_eq(thd, arg0, arg1);
if (res && !res->fix_fields(thd, &res))
{
trace_upper_removal_rewrite(thd, this, res);
return res;
}
}
}
return this;
}
/*
@brief
Rewrite "UPPER(key_col) IN (const-list)" into "key_col IN (const-list)"
*/
Item* Item_func_in::varchar_upper_cmp_transformer(THD *thd, uchar *arg)
{
if (arg_types_compatible &&
m_comparator.cmp_type() == STRING_RESULT &&
cmp_collation.collation->state & MY_CS_UPPER_EQUAL_AS_EQUAL &&
all_items_are_consts(args + 1, arg_count - 1))
{
Item *arg0= arguments()[0];
Item *tmp;
if ((tmp= is_upper_key_col(arg0)))
{
Item_func_in *cl= (Item_func_in*)build_clone(thd);
Item *res;
cl->arguments()[0]= tmp;
cl->walk(&Item::cleanup_excluding_const_fields_processor, 0, 0);
res= cl;
if (res->fix_fields(thd, &res))
return this;
trace_upper_removal_rewrite(thd, this, res);
return res;
}
}
return this;
}
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