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BUG#919878: Assertion `!eliminated_tables...

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- In MySQL 5.5, print_join() was re-worked to print "FROM dual" when all
  tables are constant. This change didn't work together with table 
  elimination.
This commit is contained in:
Sergey Petrunya
2012-02-21 01:08:22 +04:00
parent 150f238538
commit 0099593562
3 changed files with 62 additions and 2 deletions
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27
sql/sql_select.cc
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@ -21442,6 +21442,8 @@ static void print_table_array(THD *thd,
(curr->nested_join && !(curr->nested_join->used_tables &
~eliminated_tables))))
{
/* as of 5.5, print_join doesnt put eliminated elements into array */
DBUG_ASSERT(0);
continue;
}
@ -21467,6 +21469,21 @@ static void print_table_array(THD *thd,
}
/*
Check if the passed table is
- a base table which was eliminated, or
- a join nest which only contained eliminated tables (and so was eliminated,
too)
*/
static bool is_eliminated_table(table_map eliminated_tables, TABLE_LIST *tbl)
{
return eliminated_tables &&
((tbl->table && (tbl->table->map & eliminated_tables)) ||
(tbl->nested_join && !(tbl->nested_join->used_tables &
~eliminated_tables)));
}
/**
Print joins from the FROM clause.
@ -21488,8 +21505,14 @@ static void print_join(THD *thd,
uint non_const_tables= 0;
for (TABLE_LIST *t= ti++; t ; t= ti++)
if (!t->optimized_away)
{
/*
See comment in print_table_array() about the second part of the
condition
*/
if (!t->optimized_away && !is_eliminated_table(eliminated_tables, t))
non_const_tables++;
}
if (!non_const_tables)
{
str->append(STRING_WITH_LEN("dual"));
@ -21504,7 +21527,7 @@ static void print_join(THD *thd,
TABLE_LIST *tmp, **t= table + (non_const_tables - 1);
while ((tmp= ti++))
{
if (tmp->optimized_away)
if (tmp->optimized_away || is_eliminated_table(eliminated_tables, tmp))
continue;
*t--= tmp;
}