CREATE PROCEDURE did not detect unknown SP variables in assignments like this:
SET var=a_long_var_name_with_a_typo;
The error happened only during the SP execution time, and only of the control
flow reaches the erroneous statement.
Fixing most expressions to detect unknown identifiers.
This includes simple subqueries without tables:
- Query specification: SELECT list, WHERE,
HAVING (inside aggregate functions) clauses, e.g.
SET var= (SELECT unknown_ident+1);
SET var= (SELECT 1 WHERE unknown_identifier);
SET var= (SELECT 1 HAVING SUM(unknown_identifier);
- Table value constructor: VALUES clause, e.g.:
SET var= (VALUES(unknown_ident));
Note, in some more complex subquery cases unknown variables are still not detected
(this will be fixed separately):
- Derived tables:
SET a=(SELECT unknown_ident FROM (SELECT 1 AS alias) t1);
SET res=(SELECT * FROM t1 LEFT OUTER JOIN (SELECT unknown_ident) t2 USING (c1));
- CTE:
SET a=(WITH cte1 (a) AS (SELECT unknown_ident) SELECT * FROM cte1);
SET a=(WITH cte1 (a,b) AS (VALUES (unknown,2),(3,4)) SELECT * FROM cte1);
SET a=(WITH cte1 (a,b) AS (VALUES (1,2),(3,4)) SELECT unknown_ident FROM cte1);
- SELECT .. GROUP BY unknown_identifier
- SELECT .. ORDER BY unknown_identifier
- HAVING with an unknown identifier outside of any aggregate functions:
SELECT .. HAVING unknown_identifier;
query with VALUES()
A table value constructor can be used in all contexts where a select
can be used. In particular an ORDER BY clause or a LIMIT clause or both
of them can be attached to a table value constructor to produce a new
query. Unfortunately execution of such queries was not supported.
This patch fixes the problem.
value constructor shows wrong number of rows
If the specification of a derived table contained a table value constructor
then the optimizer incorrectly estimated the number of rows in the derived
table. This happened because the optimizer did not take into account the
number of rows in the constructor. The wrong estimate could lead to choosing
inefficient execution plans.
Most "new" failures fixed in the following files:
- sql_select.cc
- item.cc
- item_func.cc
- opt_subselect.cc
Other things:
- Allocate udf_handler strings in mem_root
- Required changes in sql_string.h
- Add mem_root as argument to some new [] calls
- Mark udf_handler strings as thread specific
- Removed some comment blocks with code
TVC can be used in UNION-statement, in view and in subquery.
Files where TVC is defined and its methods are stored added.
Methods exec and prepare for TVC added.
Tests for TVC added.
