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join_nested.test, join_nested.result:

Browse Source 
Added a case for bug #4976 when one of the inner tables is empty.
select.result, join.result:
  Reversed the previous change of the erronious fix for bug #4976.
sql_select.cc:
  The previous fix for bug 4976 was reversed as it
  erroniously converted an outer join into an innner join
  when on_expression does not refer to outer tables.
  This is not valid if inner tables return an empty set.
  Setting dependency on outer tables was added for the above cases.
  To fix the crash in the test case of bug #4976  
  a guard was added that blocks running the crashing code for
  nested outer joins.
This commit is contained in:
igor@rurik.mysql.com
2004-08-12 23:41:06 -07:00
parent c92db89c44
commit 49094f58f9
5 changed files with 125 additions and 12 deletions
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22
sql/sql_select.cc
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@ -2304,7 +2304,8 @@ make_join_statistics(JOIN *join,TABLE_LIST *tables,COND *conds,
if (s->worst_seeks < 2.0) // Fix for small tables
s->worst_seeks=2.0;
if (! s->const_keys.is_clear_all())
if (!s->const_keys.is_clear_all() &&
!s->table->pos_in_table_list->embedding)
{
ha_rows records;
SQL_SELECT *select;
@ -6077,10 +6078,8 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top)
table->embedding->nested_join->used_tables|= used_tables;
table->embedding->nested_join->not_null_tables|= not_null_tables;
}
if (!table->outer_join || (used_tables & not_null_tables) ||
(table->outer_join &&
!(table->on_expr->used_tables() & ~used_tables)))
if (!table->outer_join || (used_tables & not_null_tables))
{
/*
For some of the inner tables there are conjunctive predicates
@ -6130,7 +6129,20 @@ simplify_joins(JOIN *join, List<TABLE_LIST> *join_list, COND *conds, bool top)
if (prev_table->straight)
prev_table->dep_tables|= used_tables;
if (prev_table->on_expr)
{
prev_table->dep_tables|= table->on_expr_dep_tables;
table_map prev_used_tables= prev_table->nested_join ?
prev_table->nested_join->used_tables :
prev_table->table->map;
/*
If on expression contains only references to inner tables
we still make the inner tables dependent on the outer tables.
It would be enough to set dependency only on one outer table
for them. Yet this is really a rare case.
*/
if (!(prev_table->on_expr->used_tables() & ~prev_used_tables))
prev_table->dep_tables|= used_tables;
}
}
prev_table= table;
}