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MWL#90: Address review feedback part #4

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This commit is contained in:
Sergey Petrunya 2011-03-22 00:39:27 +03:00
parent 4e5dbab5a6
commit 809a805251
4 changed files with 42 additions and 40 deletions
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46
sql/opt_subselect.cc
View File

@ -687,18 +687,22 @@ bool convert_join_subqueries_to_semijoins(JOIN *join)
arena= thd->activate_stmt_arena_if_needed(&backup);
for (in_subq= join->sj_subselects.front();
in_subq != in_subq_end &&
join->tables + (*in_subq)->unit->first_select()->join->tables < MAX_TABLES;
in_subq != in_subq_end;
in_subq++)
{
bool remove_item= TRUE;
if ((*in_subq)->is_flattenable_semijoin)
{
if (join->tables +
(*in_subq)->unit->first_select()->join->tables >= MAX_TABLES)
break;
if (convert_subq_to_sj(join, *in_subq))
DBUG_RETURN(TRUE);
}
else
{
if (join->tables + 1 >= MAX_TABLES)
break;
if (convert_subq_to_jtbm(join, *in_subq, &remove_item))
DBUG_RETURN(TRUE);
}
@ -1211,6 +1215,17 @@ static bool convert_subq_to_sj(JOIN *parent_join, Item_in_subselect *subq_pred)
}
const int SUBQERY_TEMPTABLE_NAME_MAX_LEN= 20;
static void create_subquery_temptable_name(char *to, uint number)
{
DBUG_ASSERT(number < 10000);
to= strmov(to, "<subquery");
to= int10_to_str((int) number, to, 10);
to[0]= '>';
to[1]= 0;
}
/*
Convert subquery predicate into non-mergeable semi-join nest.
@ -1241,15 +1256,15 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
if (subq_pred->engine->engine_type() != subselect_engine::HASH_SJ_ENGINE)
{
*remove_item= FALSE;
make_in_exists_conversion(parent_join->thd, parent_join, subq_pred);
DBUG_RETURN(FALSE);
bool res;
res= make_in_exists_conversion(parent_join->thd, parent_join, subq_pred);
DBUG_RETURN(res);
}
*remove_item= TRUE;
TABLE_LIST *jtbm;
char *tbl_alias;
const char alias_mask[]="<subquery%d>";
if (!(tbl_alias= (char*)parent_join->thd->calloc(sizeof(alias_mask)+5)) ||
if (!(tbl_alias= (char*)parent_join->thd->calloc(SUBQERY_TEMPTABLE_NAME_MAX_LEN)) ||
!(jtbm= alloc_join_nest(parent_join->thd))) //todo: this is not a join nest!
{
DBUG_RETURN(TRUE);
@ -1268,7 +1283,8 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
Inject the jtbm table into TABLE_LIST::next_leaf list, so that
make_join_statistics() and co. can find it.
*/
for (tl= parent_lex->leaf_tables; tl->next_leaf; tl= tl->next_leaf) ;
for (tl= parent_lex->leaf_tables; tl->next_leaf; tl= tl->next_leaf)
{}
tl->next_leaf= jtbm;
/*
@ -1276,7 +1292,8 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
(a theory: a next_local chain always starts with ::leaf_tables
because view's tables are inserted after the view)
*/
for (tl= parent_lex->leaf_tables; tl->next_local; tl= tl->next_local) ;
for (tl= parent_lex->leaf_tables; tl->next_local; tl= tl->next_local)
{}
tl->next_local= jtbm;
/* A theory: no need to re-connect the next_global chain */
@ -1289,15 +1306,16 @@ static bool convert_subq_to_jtbm(JOIN *parent_join,
jtbm->table->map= table_map(1) << (parent_join->tables);
parent_join->tables++;
DBUG_ASSERT(parent_join->tables < MAX_TABLES);
Item *conds= hash_sj_engine->semi_join_conds;
conds->fix_after_pullout(parent_lex, &conds);
DBUG_EXECUTE("where", print_where(conds,"SJ-EXPR", QT_ORDINARY););
my_snprintf(tbl_alias, sizeof(alias_mask)+5, alias_mask,
hash_sj_engine->materialize_join->select_lex->select_number);
jtbm->alias= tbl_alias;
create_subquery_temptable_name(tbl_alias, hash_sj_engine->materialize_join->
select_lex->select_number);
jtbm->alias= tbl_alias;
/* Inject sj_on_expr into the parent's WHERE or ON */
if (emb_tbl_nest)
@ -4017,13 +4035,13 @@ enum_nested_loop_state join_tab_execution_startup(JOIN_TAB *tab)
{
/* It's a merged SJM nest */
enum_nested_loop_state rc;
JOIN *join= tab->join;
SJ_MATERIALIZATION_INFO *sjm= tab->bush_children->start->emb_sj_nest->sj_mat_info;
JOIN_TAB *join_tab= tab->bush_children->start;
JOIN_TAB *save_return_tab= join->return_tab;
if (!sjm->materialized)
{
JOIN *join= tab->join;
JOIN_TAB *join_tab= tab->bush_children->start;
JOIN_TAB *save_return_tab= join->return_tab;
/*
Now run the join for the inner tables. The first call is to run the
join, the second one is to signal EOF (this is essential for some

2
sql/sql_base.cc
View File

@ -7784,7 +7784,7 @@ bool setup_tables(THD *thd, Name_resolution_context *context,
Item *item= table_list->jtbm_subselect;
if (item->fix_fields(thd, &item))
{
my_error(ER_TOO_MANY_TABLES,MYF(0),MAX_TABLES);
my_error(ER_TOO_MANY_TABLES,MYF(0),MAX_TABLES); /* psergey-todo: WHY ER_TOO_MANY_TABLES ???*/
DBUG_RETURN(1);
}
DBUG_ASSERT(item == table_list->jtbm_subselect);

32
sql/sql_select.cc
View File

@ -6991,9 +6991,8 @@ JOIN::make_simple_join(JOIN *parent, TABLE *temp_table)
join_tab= parent->join_tab_reexec;
table= &parent->table_reexec[0]; parent->table_reexec[0]= temp_table;
top_jtrange_tables= 1;
tables= top_jtrange_tables= 1;
tables= 1;
const_tables= 0;
const_table_map= 0;
eliminated_tables= 0;
@ -8417,11 +8416,8 @@ no_join_cache:
void check_join_cache_usage_for_tables(JOIN *join, ulonglong options,
uint no_jbuf_after)
{
//JOIN_TAB *first_sjm_table= NULL;
//JOIN_TAB *last_sjm_table= NULL;
JOIN_TAB *tab;
//for (uint i= join->const_tables; i < join->tables; i++)
for (tab= first_linear_tab(join, TRUE);
tab;
tab= next_linear_tab(join, tab, TRUE))
@ -8429,23 +8425,10 @@ void check_join_cache_usage_for_tables(JOIN *join, ulonglong options,
tab->used_join_cache_level= join->max_allowed_join_cache_level;
}
//for (uint i= join->const_tables; i < join->tables; i++)
for (tab= first_linear_tab(join, TRUE);
tab;
tab= next_linear_tab(join, tab, TRUE))
{
#if 0
if (sj_is_materialize_strategy(join->best_positions[i].sj_strategy))
{
first_sjm_table= tab;
last_sjm_table= tab + join->best_positions[i].n_sj_tables;
for (JOIN_TAB *sjm_tab= first_sjm_table;
sjm_tab != last_sjm_table; sjm_tab++)
sjm_tab->first_sjm_sibling= first_sjm_table;
}
if (!(tab >= first_sjm_table && tab < last_sjm_table))
tab->first_sjm_sibling= NULL;
#endif
JOIN_TAB *prev_tab;
restart:
tab->icp_other_tables_ok= TRUE;
@ -8471,10 +8454,6 @@ restart:
we can first allocate a join buffer, then decide not to use it and free
it.
*/
/*
if (join->return_tab)
i= join->return_tab-join->join_tab-1; // always >= 0
*/
if (join->return_tab)
{
tab= join->return_tab;
@ -19617,12 +19596,19 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order,
examined_rows= tab->limit;
else
{
//tab->table->file->info(HA_STATUS_VARIABLE);
if (!tab->table->pos_in_table_list ||
tab->table->is_filled_at_execution()) // temporary, is_filled_at_execution
{
examined_rows= tab->records;
}
else
{
/*
handler->info(HA_STATUS_VARIABLE) has been called in
make_join_statistics()
*/
examined_rows= tab->table->file->stats.records;
}
}
}
else

2
sql/sql_show.cc
View File

@ -6600,14 +6600,12 @@ int make_schema_select(THD *thd, SELECT_LEX *sel,
bool get_schema_tables_result(JOIN *join,
enum enum_schema_table_state executed_place)
{
//JOIN_TAB *tmp_join_tab= join->join_tab+join->tables;
THD *thd= join->thd;
LEX *lex= thd->lex;
bool result= 0;
DBUG_ENTER("get_schema_tables_result");
thd->no_warnings_for_error= 1;
//for (JOIN_TAB *tab= join->join_tab; tab < tmp_join_tab; tab++)
for (JOIN_TAB *tab= first_linear_tab(join, FALSE);
tab;
tab= next_linear_tab(join, tab, FALSE))