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Fix valgrind failure in subselect3.test, "Conditional jump or move

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depends on uninitialised value(s) in JOIN::save_explain_data_intern"
- Make find_best()  /* the old join optimizer code */ also use table
  condition selectivity.
This commit is contained in:
Sergey Petrunya 2013-10-17 09:45:31 +04:00
parent b88bf50ec1
commit dd6bd8bfbd
1 changed files with 20 additions and 7 deletions
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27
sql/sql_select.cc
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@ -108,7 +108,7 @@ C_MODE_END
tested and approved.
*/
static bool find_best(JOIN *join,table_map rest_tables,uint index,
double record_count,double read_time);
double record_count,double read_time, uint use_cond_selectivity);
static uint cache_record_length(JOIN *join,uint index);
bool get_best_combination(JOIN *join);
static store_key *get_store_key(THD *thd,
@ -6376,8 +6376,11 @@ choose_plan(JOIN *join, table_map join_tables)
the greedy version. Will be removed when greedy_search is approved.
*/
join->best_read= DBL_MAX;
if (find_best(join, join_tables, join->const_tables, 1.0, 0.0))
if (find_best(join, join_tables, join->const_tables, 1.0, 0.0,
use_cond_selectivity))
{
DBUG_RETURN(TRUE);
}
}
else
{
@ -7576,7 +7579,7 @@ best_extension_by_limited_search(JOIN *join,
*/
static bool
find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
double read_time)
double read_time, uint use_cond_selectivity)
{
DBUG_ENTER("find_best");
THD *thd= join->thd;
@ -7627,20 +7630,30 @@ find_best(JOIN *join,table_map rest_tables,uint idx,double record_count,
advance_sj_state(join, rest_tables, idx, &current_record_count,
&current_read_time, &loose_scan_pos);
if (best_record_count > current_record_count ||
double pushdown_cond_selectivity= 1.0;
if (use_cond_selectivity > 1)
pushdown_cond_selectivity= table_cond_selectivity(join, idx, s,
rest_tables &
~real_table_bit);
join->positions[idx].cond_selectivity= pushdown_cond_selectivity;
double partial_join_cardinality= current_record_count *
pushdown_cond_selectivity;
if (best_record_count > partial_join_cardinality ||
best_read_time > current_read_time ||
(idx == join->const_tables && s->table == join->sort_by_table))
{
if (best_record_count >= current_record_count &&
if (best_record_count >= partial_join_cardinality &&
best_read_time >= current_read_time &&
(!(s->key_dependent & rest_tables) || records < 2.0))
{
best_record_count=current_record_count;
best_record_count= partial_join_cardinality;
best_read_time=current_read_time;
}
swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
if (find_best(join,rest_tables & ~real_table_bit,idx+1,
current_record_count,current_read_time))
partial_join_cardinality,current_read_time,
use_cond_selectivity))
DBUG_RETURN(TRUE);
swap_variables(JOIN_TAB*, join->best_ref[idx], *pos);
}