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Merge mysql.com:/opt/local/work/mysql-5.0-for-merge

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into  mysql.com:/opt/local/work/mysql-5.1-merge1


mysql-test/r/ps.result:
  Auto merged
mysql-test/t/ps.test:
  Auto merged
sql/item_cmpfunc.cc:
  Auto merged
sql/sql_select.cc:
  Auto merged
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unknown
2006-01-26 16:36:33 +03:00
parent 1de00282d4 4e107f1147
commit 9853390f4c
7 changed files with 162 additions and 15 deletions
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72
sql/sql_select.cc
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@ -2960,6 +2960,56 @@ sort_keyuse(KEYUSE *a,KEYUSE *b)
}
/*
Add to KEY_FIELD array all 'ref' access candidates within nested join
SYNPOSIS
add_key_fields_for_nj()
nested_join_table IN Nested join pseudo-table to process
end INOUT End of the key field array
and_level INOUT And-level
DESCRIPTION
This function populates KEY_FIELD array with entries generated from the
ON condition of the given nested join, and does the same for nested joins
contained within this nested join.
NOTES
We can add accesses to the tables that are direct children of this nested
join (1), and are not inner tables w.r.t their neighbours (2).
Example for #1 (outer brackets pair denotes nested join this function is
invoked for):
... LEFT JOIN (t1 LEFT JOIN (t2 ... ) ) ON cond
Example for #2:
... LEFT JOIN (t1 LEFT JOIN t2 ) ON cond
In examples 1-2 for condition cond, we can add 'ref' access candidates to
t1 only.
Example #3:
... LEFT JOIN (t1, t2 LEFT JOIN t3 ON inner_cond) ON cond
Here we can add 'ref' access candidates for t1 and t2, but not for t3.
*/
static void add_key_fields_for_nj(TABLE_LIST *nested_join_table,
KEY_FIELD **end, uint *and_level)
{
List_iterator<TABLE_LIST> li(nested_join_table->nested_join->join_list);
table_map tables= 0;
TABLE_LIST *table;
DBUG_ASSERT(nested_join_table->nested_join);
while ((table= li++))
{
if (table->nested_join)
add_key_fields_for_nj(table, end, and_level);
else
if (!table->on_expr)
tables |= table->table->map;
}
add_key_fields(end, and_level, nested_join_table->on_expr, tables);
}
/*
Update keyuse array with all possible keys we can use to fetch rows
@ -3024,23 +3074,21 @@ update_ref_and_keys(THD *thd, DYNAMIC_ARRAY *keyuse,JOIN_TAB *join_tab,
into account as well.
*/
if (*join_tab[i].on_expr_ref)
{
add_key_fields(&end,&and_level,*join_tab[i].on_expr_ref,
join_tab[i].table->map);
}
else
}
/* Process ON conditions for the nested joins */
{
List_iterator<TABLE_LIST> li(*join_tab->join->join_list);
TABLE_LIST *table;
while ((table= li++))
{
TABLE_LIST *tab= join_tab[i].table->pos_in_table_list;
TABLE_LIST *embedding= tab->embedding;
if (embedding)
{
NESTED_JOIN *nested_join= embedding->nested_join;
if (nested_join->join_list.head() == tab)
add_key_fields(&end, &and_level, embedding->on_expr,
nested_join->used_tables);
}
if (table->nested_join)
add_key_fields_for_nj(table, &end, &and_level);
}
}
/* fill keyuse with found key parts */
for ( ; field != end ; field++)
add_key_part(keyuse,field);