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Fixed an incorrect calculation of JOIN_CACHE::max_buff_size.

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This commit is contained in:
Igor Babaev
2010-09-01 23:11:14 -07:00
parent 5dec6cca5f
commit f83cc50793
4 changed files with 25 additions and 6 deletions
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13
sql/sql_select.cc
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@ -7720,6 +7720,9 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
setup_semijoin_dups_elimination(join, options, no_jbuf_after))
DBUG_RETURN(TRUE); /* purecov: inspected */
for (i= 0; i < join->const_tables; i++)
join->join_tab[i].partial_join_cardinality= 1;
for (i=join->const_tables ; i < join->tables ; i++)
{
JOIN_TAB *tab=join->join_tab+i;
@ -7731,6 +7734,16 @@ make_join_readinfo(JOIN *join, ulonglong options, uint no_jbuf_after)
tab->next_select=sub_select; /* normal select */
tab->sorted= sorted;
sorted= 0; // only first must be sorted
/*
The approximation below for partial join cardinality is not good because
- it does not take into account some pushdown predicates
- it does not differentiate between inner joins, outer joins and semi-joins.
Later it should be improved.
*/
tab->partial_join_cardinality= join->best_positions[i].records_read *
(i ? (tab-1)->partial_join_cardinality : 1);
if (tab->loosescan_match_tab)
{
if (!(tab->loosescan_buf= (uchar*)join->thd->alloc(tab->