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unknown
2010-09-08 09:26:17 +03:00
parent d6a9b52269
commit 11dc256ca4
6 changed files with 170 additions and 66 deletions
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63
sql/sql_expression_cache.cc
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@ -12,63 +12,13 @@ Expression_cache_tmptable::Expression_cache_tmptable(THD *thd,
List<Item*> &dependants,
Item *value)
:cache_table(NULL), table_thd(thd), list(&dependants), val(value),
equalities(NULL), inited (0)
inited (0)
{
DBUG_ENTER("Expression_cache_tmptable::Expression_cache_tmptable");
DBUG_VOID_RETURN;
};
/**
Build and of equalities for the expression's parameters of certain types
@details
If the temporary table used as an expression cache contains fields of
certain types then it's not enough to perform a lookup into the table to
verify that there is no row in the table for a given set of parameters.
Additionally for those fields we have to check equalities of the form
fld=val, where val is the value of the parameter stored in the column
fld.
The function generates a conjunction of all such equality predicates
and saves a pointer to it in the field 'equalities'.
@retval FALSE OK
@retval TRUE Error
*/
bool Expression_cache_tmptable::make_equalities()
{
List<Item> args;
List_iterator_fast<Item*> li(*list);
Item **ref;
DBUG_ENTER("Expression_cache_tmptable::make_equalities");
for (uint i= 1 /* skip result filed */; (ref= li++); i++)
{
Field *fld= cache_table->field[i];
/* Only some field types should be checked after lookup */
if (fld->type() == MYSQL_TYPE_VARCHAR ||
fld->type() == MYSQL_TYPE_TINY_BLOB ||
fld->type() == MYSQL_TYPE_MEDIUM_BLOB ||
fld->type() == MYSQL_TYPE_LONG_BLOB ||
fld->type() == MYSQL_TYPE_BLOB ||
fld->type() == MYSQL_TYPE_VAR_STRING ||
fld->type() == MYSQL_TYPE_STRING ||
fld->type() == MYSQL_TYPE_NEWDECIMAL ||
fld->type() == MYSQL_TYPE_DECIMAL)
{
args.push_front(new Item_func_eq(*ref, new Item_field(fld)));
}
}
if (args.elements == 1)
equalities= args.head();
else
equalities= new Item_cond_and(args);
DBUG_RETURN(equalities->fix_fields(table_thd, &equalities));
}
/**
Field enumerator for TABLE::add_tmp_key
@ -166,7 +116,8 @@ void Expression_cache_tmptable::init()
if (cache_table->alloc_keys(1) ||
(cache_table->add_tmp_key(0, items.elements - 1,
&field_enumerator,
(uchar*)&field_counter) < 0) ||
(uchar*)&field_counter,
TRUE) < 0) ||
ref.tmp_table_index_lookup_init(table_thd, cache_table->key_info, it,
TRUE))
{
@ -193,12 +144,6 @@ void Expression_cache_tmptable::init()
goto error;
}
if (make_equalities())
{
DBUG_PRINT("error", ("Creating equalities failed"));
goto error;
}
DBUG_VOID_RETURN;
error:
@ -249,7 +194,7 @@ Expression_cache::result Expression_cache_tmptable::check_value(Item **value)
(uint)cache_table->status, (uint)ref.has_record));
if ((res= join_read_key2(table_thd, NULL, cache_table, &ref)) == 1)
DBUG_RETURN(ERROR);
if (res || (equalities && !equalities->val_int()))
if (res)
{
subquery_cache_miss++;
DBUG_RETURN(MISS);