Commit 6a01d8bc authored by heikki@donna.mysql.fi's avatar heikki@donna.mysql.fi
Browse files

ha_innobase.cc: 

  Do not automatically calculate new statistics when a temporary table is used by MySQL in a query. The fact that some ORDER BY queries were slow may have been explained by this unnecessary statistics calculation.
parent d3a22100

sql/ha_innobase.cc

+7 −4
Original line number Diff line number Diff line
@@ -3035,15 +3035,18 @@ ha_innobase::estimate_number_of_rows(void) 


 	DBUG_ENTER("info");



 	dict_update_statistics(prebuilt->table);



	index = dict_table_get_first_index_noninline(prebuilt->table);

 	

	data_file_length = ((ulonglong) index->stat_n_leaf_pages)

    							* UNIV_PAGE_SIZE;

	/* Calculate a minimum length for a clustered index record */



	estimate = data_file_length / dict_index_calc_min_rec_len(index);

	/* Calculate a minimum length for a clustered index record and from

	that an upper bound for the number of rows. Since we only calculate

	new statistics in row0mysql.c when a table size has grown by 50 %

	or by a threshold factor, we must add a safety factor 2 in front

	of the formula below. */



	estimate = 2 * data_file_length / dict_index_calc_min_rec_len(index);

	

	if (prebuilt->trx) {

		prebuilt->trx->op_info = "";