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MDEV-406: ANALYZE $stmt

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- Support tracking for UNIONs, temporary-table based ORDER BYs,
  and both.
This commit is contained in:
Sergei Petrunia
2014-06-03 17:59:01 +04:00
parent 0925ab9d88
commit 5621aa3230
6 changed files with 79 additions and 17 deletions
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39
sql/sql_select.cc
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@@ -1032,6 +1032,9 @@ int JOIN::optimize()
subquery), returns 1
- another JOIN::optimize() call made, and now join->optimize() will
return 0, even though we never had a query plan.
Can have QEP_NOT_PRESENT_YET for degenerate queries (for example,
SELECT * FROM tbl LIMIT 0)
*/
if (was_optimized != optimized && !res && have_query_plan != QEP_DELETED)
{
@@ -2350,6 +2353,20 @@ void JOIN::save_explain_data(Explain_query *output, bool can_overwrite,
}
save_explain_data_intern(thd->lex->explain, need_tmp_table, need_order,
distinct, message);
return;
}
/*
Can have join_tab==NULL for degenerate cases (e.g. SELECT .. UNION ... SELECT LIMIT 0)
*/
if (select_lex == select_lex->master_unit()->fake_select_lex && join_tab)
{
/*
This is fake_select_lex. It has no query plan, but we need to set up a
tracker for ANALYZE
*/
Explain_union *eu= output->get_union(select_lex->master_unit()->first_select()->select_number);
join_tab[0].tracker= eu->get_fake_select_lex_tracker();
}
}
@@ -8958,6 +8975,20 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
join_tab->read_first_record= join_init_read_record;
join_tab->join= this;
join_tab->ref.key_parts= 0;
uint select_nr= select_lex->select_number;
if (select_nr == INT_MAX)
{
/* this is a fake_select_lex of a union */
select_nr= select_lex->master_unit()->first_select()->select_number;
join_tab->tracker= thd->lex->explain->get_union(select_nr)->
get_tmptable_read_tracker();
}
else
{
join_tab->tracker= thd->lex->explain->get_select(select_nr)->
get_using_temporary_read_tracker();
}
bzero((char*) &join_tab->read_record,sizeof(join_tab->read_record));
temp_table->status=0;
temp_table->null_row=0;
@@ -17532,7 +17563,7 @@ sub_select(JOIN *join,JOIN_TAB *join_tab,bool end_of_records)
(*join_tab->next_select)(join,join_tab+1,end_of_records);
DBUG_RETURN(nls);
}
join_tab->explain->r_scans++;
join_tab->tracker->r_scans++;
int error;
enum_nested_loop_state rc= NESTED_LOOP_OK;
@@ -17669,7 +17700,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
DBUG_RETURN(NESTED_LOOP_KILLED); /* purecov: inspected */
}
join_tab->explain->r_rows++;
join_tab->tracker->r_rows++;
if (join_tab->table->vfield)
update_virtual_fields(join->thd, join_tab->table);
@@ -17689,7 +17720,7 @@ evaluate_join_record(JOIN *join, JOIN_TAB *join_tab,
There is no select condition or the attached pushed down
condition is true => a match is found.
*/
join_tab->explain->r_rows_after_table_cond++;
join_tab->tracker->r_rows_after_table_cond++;
bool found= 1;
while (join_tab->first_unmatched && found)
{
@@ -23315,7 +23346,7 @@ int JOIN::save_explain_data_intern(Explain_query *output, bool need_tmp_table,
eta->key.set(thd->mem_root, NULL, (uint)-1);
eta->quick_info= NULL;
tab->explain= eta;
tab->tracker= &eta->tracker;
/* id */
if (tab->bush_root_tab)