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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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4
mysql-test/r/subselect_sj_jcl6.result Executable file → Normal file
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@ -723,7 +723,6 @@ WHERE int_nokey IN (SELECT it2.int_key
FROM it1 LEFT JOIN it2 ON it2.datetime_key);
int_key
0
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2
0
7
@ -734,10 +733,11 @@ int_key
0
0
0
0
3
7
7
8
0
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EXPLAIN
SELECT int_key FROM ot1

7
sql/sql_join_cache.cc
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@ -747,7 +747,7 @@ ulong JOIN_CACHE::get_max_join_buffer_size()
if (join_tab->join_buffer_size_limit)
set_if_smaller(limit_sz, join_tab->join_buffer_size_limit);
if (limit_sz / max_records > space_per_record)
max_sz*= space_per_record * max_records;
max_sz= space_per_record * max_records;
else
max_sz= limit_sz;
max_sz+= pack_length_with_blob_ptrs;
@ -790,15 +790,18 @@ int JOIN_CACHE::alloc_buffer()
{
JOIN_TAB *tab;
JOIN_CACHE *cache;
uint i= join->const_tables;
ulonglong curr_buff_space_sz= 0;
ulonglong curr_min_buff_space_sz= 0;
ulonglong join_buff_space_limit=
join->thd->variables.join_buff_space_limit;
double partial_join_cardinality= (join_tab-1)->get_partial_join_cardinality();
buff= NULL;
min_buff_size= 0;
max_buff_size= 0;
min_records= 1;
max_records= join_tab->records;
max_records= partial_join_cardinality <= join_buff_space_limit ?
(ulonglong) partial_join_cardinality : join_buff_space_limit;
set_if_bigger(max_records, 1);
min_buff_size= get_min_join_buffer_size();
buff_size= get_max_join_buffer_size();

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->

3
sql/sql_select.h
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@ -217,6 +217,8 @@ typedef struct st_join_table {
*/
ha_rows read_time;
double partial_join_cardinality;
table_map dependent,key_dependent;
uint use_quick,index;
uint status; ///< Save status for cache
@ -386,6 +388,7 @@ typedef struct st_join_table {
calc_used_field_length(TRUE);
return max_used_fieldlength;
}
double get_partial_join_cardinality() { return partial_join_cardinality; }
} JOIN_TAB;