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[SHOW] EXPLAIN UPDATE/DELETE, code re-structuring

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Single table UPDATE/DELETE
- Correctly print type=SIMPLE vs type=PRIMARY
- Handle UPDATE/DELETE of mergeable VIEWs: we get the 
  VIEW's select as the first subquery. 
  (MySQL 5.6 doesn't print it because it finds that the
   subquery is not attached to any select)
This commit is contained in:
Sergey Petrunya 2013-06-20 20:58:26 +04:00
parent 0a560289aa
commit 52cfa54c1d
7 changed files with 64 additions and 17 deletions
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2
mysql-test/r/explain_non_select.result
View File

@ -1,4 +1,4 @@
drop table if exists t0;
drop table if exists t0, t1;
create table t0 (a int) engine=myisam;
insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
#

10
sql/opt_qpf.cc
View File

@ -49,6 +49,7 @@ void QPF_query::add_node(QPF_node *node)
if (node->get_type() == QPF_node::QPF_UNION)
{
QPF_union *u= (QPF_union*)node;
DBUG_ASSERT(!unions[u->get_select_id()]);
unions[u->get_select_id()]= u;
}
else
@ -60,7 +61,10 @@ void QPF_query::add_node(QPF_node *node)
DBUG_ASSERT(0);
}
else
{
DBUG_ASSERT(!selects[sel->select_id]);
selects[sel->select_id] = sel;
}
}
}
@ -493,7 +497,7 @@ int QPF_delete::print_explain(QPF_query *query, select_result_sink *output,
const char *msg= "Deleting all rows";
int res= print_explain_message_line(output, explain_flags,
1 /*select number*/,
"SIMPLE", msg);
select_type, msg);
return res;
}
@ -513,7 +517,7 @@ int QPF_update::print_explain(QPF_query *query, select_result_sink *output,
const char *msg= "Impossible where";
int res= print_explain_message_line(output, explain_flags,
1 /*select number*/,
"SIMPLE", msg);
select_type, msg);
return res;
}
@ -541,7 +545,7 @@ int QPF_update::print_explain(QPF_query *query, select_result_sink *output,
print_explain_row(output, explain_flags,
1, /* id */
"SIMPLE",
select_type,
table_name.c_ptr(),
// partitions,
jtype,

2
sql/opt_qpf.h
View File

@ -350,6 +350,8 @@ public:
virtual enum qpf_node_type get_type() { return QPF_UPDATE; }
virtual int get_select_id() { return 1; /* always root */ }
const char *select_type;
bool impossible_where;
StringBuffer<64> table_name;

42
sql/sql_delete.cc
View File

@ -58,10 +58,12 @@ void Delete_plan::save_query_plan_footprint(QPF_query *query)
if (deleting_all_rows)
{
qpf->deleting_all_rows= true;
qpf->select_type= "SIMPLE";
}
else
{
Update_plan::save_query_plan_footprint_intern(qpf);
qpf->deleting_all_rows= false;
Update_plan::save_query_plan_footprint_intern(query, qpf);
}
query->upd_del_plan= qpf;
@ -71,13 +73,14 @@ void Delete_plan::save_query_plan_footprint(QPF_query *query)
void Update_plan::save_query_plan_footprint(QPF_query *query)
{
QPF_update* qpf= new QPF_update;
save_query_plan_footprint_intern(qpf);
save_query_plan_footprint_intern(query, qpf);
query->upd_del_plan= qpf;
}
void Update_plan::save_query_plan_footprint_intern(QPF_update *qpf)
void Update_plan::save_query_plan_footprint_intern(QPF_query *query, QPF_update *qpf)
{
qpf->select_type= "SIMPLE";
qpf->table_name.append(table->pos_in_table_list->alias);
if (impossible_where)
{
@ -85,8 +88,10 @@ void Update_plan::save_query_plan_footprint_intern(QPF_update *qpf)
return;
}
// TODO: do we need the following: select_type
//select_lex->set_explain_type(TRUE);
qpf->impossible_where= false;
select_lex->set_explain_type(TRUE);
qpf->select_type= select_lex->type;
/* Set jtype */
if (select && select->quick)
@ -134,6 +139,28 @@ void Update_plan::save_query_plan_footprint_intern(QPF_update *qpf)
{
explain_append_mrr_info((QUICK_RANGE_SELECT*)select->quick, &qpf->mrr_type);
}
bool skip= updating_a_view;
/* Save subquery children */
for (SELECT_LEX_UNIT *unit= select_lex->first_inner_unit();
unit;
unit= unit->next_unit())
{
if (skip)
{
skip= false;
continue;
}
/*
Display subqueries only if they are not parts of eliminated WHERE/ON
clauses.
*/
if (!(unit->item && unit->item->eliminated))
qpf->add_child(unit->first_select()->select_number);
//TODO: temporary?:
unit->save_qpf(query);
}
}
@ -194,6 +221,9 @@ bool mysql_delete(THD *thd, TABLE_LIST *table_list, COND *conds,
query_plan.select_lex= &thd->lex->select_lex;
query_plan.table= table;
//psergey-todo: Ugly, discuss with Sanja
query_plan.updating_a_view= test(table_list->view);
if (mysql_prepare_delete(thd, table_list, &conds))
DBUG_RETURN(TRUE);
@ -612,7 +642,7 @@ exit_without_my_ok:
List<Item> dummy; /* note: looked in 5.6 and they too use a dummy list like this */
result->prepare(dummy, &thd->lex->unit);
thd->send_explain_fields(result);
int err2= thd->lex->query_plan_footprint->print_explain(result, 0);
int err2= thd->lex->query_plan_footprint->print_explain(result, 0 /* explain flags*/);
if (err2)
result->abort_result_set();

7
sql/sql_lex.cc
View File

@ -4337,6 +4337,13 @@ int st_select_lex_unit::save_qpf(QPF_query *output)
{
//int res= 0;
SELECT_LEX *first= first_select();
if (!first->next_select())
{
/* This is a 1-way UNION, i.e. not really a UNION */
first->save_qpf(output);
return 0;
}
QPF_union *qpfu= new QPF_union;
/*

8
sql/sql_lex.h
View File

@ -730,10 +730,7 @@ public:
friend int subselect_union_engine::exec();
List<Item> *get_unit_column_types();
#if 0
int print_explain(select_result_sink *output, uint8 explain_flags,
bool *printed_anything);
#endif
int save_qpf(QPF_query *output);
};
@ -2379,6 +2376,7 @@ class Update_plan
protected:
bool impossible_where;
public:
bool updating_a_view;
TABLE *table;
SQL_SELECT *select;
uint index;
@ -2396,7 +2394,7 @@ public:
void set_impossible_where() { impossible_where= true; }
void save_query_plan_footprint(QPF_query *query);
void save_query_plan_footprint_intern(QPF_update *qpf);
void save_query_plan_footprint_intern(QPF_query *query, QPF_update *qpf);
virtual ~Update_plan() {}
Update_plan() : impossible_where(false), using_filesort(false) {}

10
sql/sql_update.cc
View File

@ -314,6 +314,10 @@ int mysql_update(THD *thd,
my_error(ER_NON_UPDATABLE_TABLE, MYF(0), table_list->alias, "UPDATE");
DBUG_RETURN(1);
}
//psergey-todo: Ugly, discuss with Sanja
query_plan.updating_a_view= test(table_list->view);
/* Calculate "table->covering_keys" based on the WHERE */
table->covering_keys= table->s->keys_in_use;
table->quick_keys.clear_all();
@ -1013,13 +1017,14 @@ exit_without_my_ok:
query_plan.save_query_plan_footprint(thd->lex->query_plan_footprint);
select_send *result;
bool printed_anything;
//bool printed_anything;
if (!(result= new select_send()))
return 1; /* purecov: inspected */
List<Item> dummy; /* note: looked in 5.6 and they too use a dummy list like this */
result->prepare(dummy, &thd->lex->unit);
thd->send_explain_fields(result);
int err2= thd->lex->print_explain(result, 0 /* explain flags*/, &printed_anything);
//int err2= thd->lex->print_explain(result, 0 /* explain flags*/, &printed_anything);
int err2= thd->lex->query_plan_footprint->print_explain(result, 0 /* explain flags*/);
if (err2)
result->abort_result_set();
@ -1498,6 +1503,7 @@ bool mysql_multi_update(THD *thd,
{
if (explain)
{
thd->lex->query_plan_footprint->print_explain(output, 0);
output->send_eof();
delete output;
}