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BUG#16393: post-review fixes: fix comments.

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unknown 2006-01-14 01:26:42 +03:00
parent 2956a79b93
commit e6693c1303
1 changed files with 5 additions and 13 deletions
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18
sql/sql_select.cc
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@ -2925,34 +2925,26 @@ sort_keyuse(KEYUSE *a,KEYUSE *b)
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.
IMPLEMENTATION
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 JOIN t3 ON inner_cond) ON cond
... 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,
@ -2969,7 +2961,7 @@ static void add_key_fields_for_nj(TABLE_LIST *nested_join_table,
add_key_fields_for_nj(table, end, and_level);
else
if (!table->on_expr)
tables |= table->table->map;
tables |= table->table->map;
}
add_key_fields(end, and_level, nested_join_table->on_expr, tables);
}