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MWL#17: Table elimination

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- Fix the previous cset: take into account that select_lex may be printed when 
 1. There is no select_lex->join at all (in that case, assume that no tables were eliminated)
 2. select_lex->join exists but there was no JOIN::optimize() call yet. handle this by initializing join->eliminated really early.
This commit is contained in:
Sergey Petrunia 2009-06-14 16:35:04 +04:00
parent 402e58cf78
commit b1e25edc9b
2 changed files with 4 additions and 3 deletions
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6
sql/sql_select.cc
View File

@ -2731,7 +2731,7 @@ static void eliminate_tables(JOIN *join, uint *const_tbl_count, table_map *const
table_map used_tables;
DBUG_ENTER("eliminate_tables");
join->eliminated_tables= 0;
DBUG_ASSERT(join->eliminated_tables == 0);
/* MWL#17 is only about outer join elimination, so: */
if (!join->outer_join)
@ -16888,7 +16888,7 @@ bool mysql_explain_union(THD *thd, SELECT_LEX_UNIT *unit, select_result *result)
unit->fake_select_lex->options|= SELECT_DESCRIBE;
if (!(res= unit->prepare(thd, result, SELECT_NO_UNLOCK | SELECT_DESCRIBE)))
res= unit->exec();
res|= unit->cleanup();
//psergey-move: res|= unit->cleanup();
}
else
{
@ -17164,7 +17164,7 @@ void st_select_lex::print(THD *thd, String *str, enum_query_type query_type)
{
str->append(STRING_WITH_LEN(" from "));
/* go through join tree */
print_join(thd, join->eliminated_tables, str, &top_join_list, query_type);
print_join(thd, join? join->eliminated_tables: 0, str, &top_join_list, query_type);
}
else if (where)
{

1
sql/sql_select.h
View File

@ -427,6 +427,7 @@ public:
table= 0;
tables= 0;
const_tables= 0;
eliminated_tables= 0;
join_list= 0;
sort_and_group= 0;
first_record= 0;