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remove unused group_by_handler::init() method

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The assumption is that the engine should not need to
evaluate HAVING on the table->record[0] - the engine either
can evaluate HAVING internally before writing it to the
table->record[0], or it should leave it to the server,
that will evaluate HAVING(table->record[0]).

Similarly the engine should not need to evaluate ORDER
on the table->record[0]. Either it returns the data already
sorted, or the server will sort the table.
This commit is contained in:
Sergei Golubchik 2015-10-03 08:22:17 +02:00
parent 21175bb316
commit 3abfe76e2d
2 changed files with 2 additions and 30 deletions
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24
sql/group_by_handler.h
View File

@ -74,30 +74,6 @@ public:
: thd(thd_arg), ht(ht_arg), table(0) {} : thd(thd_arg), ht(ht_arg), table(0) {}
virtual ~group_by_handler() {} virtual ~group_by_handler() {}
/*
Store pointer to temporary table and objects modified to point to
the temporary table. This will happen during the optimize phase.
We provide new 'having' and 'order_by' elements here. The differ from the
original ones in that these are modified to point to fields in the
temporary table 'table'.
Return 1 if the storage handler cannot handle the GROUP BY after all,
in which case we have to give an error to the end user for the query.
This is becasue we can't revert back the old having and order_by elements.
*/
virtual bool init(Item *having_arg, ORDER *order_by_arg)
{
return 0;
}
bool ha_init(TABLE *temporary_table, Item *having_arg, ORDER *order_by_arg)
{
table= temporary_table;
return init(having_arg, order_by_arg);
}
/* /*
Functions to scan data. All these returns 0 if ok, error code in case Functions to scan data. All these returns 0 if ok, error code in case
of error of error

8
sql/sql_select.cc
View File

@ -1922,7 +1922,6 @@ JOIN::optimize_inner()
if (gbh) if (gbh)
{ {
pushdown_query= new (thd->mem_root) Pushdown_query(select_lex, gbh); pushdown_query= new (thd->mem_root) Pushdown_query(select_lex, gbh);
int err;
/* /*
We must store rows in the tmp table if we need to do an ORDER BY We must store rows in the tmp table if we need to do an ORDER BY
@ -1953,11 +1952,8 @@ JOIN::optimize_inner()
DBUG_RETURN(1); DBUG_RETURN(1);
/* Give storage engine access to temporary table */ /* Give storage engine access to temporary table */
if ((err= gbh->ha_init(exec_tmp_table1, having, order))) gbh->table= exec_tmp_table1;
{
gbh->print_error(err, MYF(0));
DBUG_RETURN(1);
}
pushdown_query->store_data_in_temp_table= need_tmp; pushdown_query->store_data_in_temp_table= need_tmp;
pushdown_query->having= having; pushdown_query->having= having;
/* /*