wl#820 also has table functions in it:
http://antbits.blogspot.com/2009/01/table-functions-in-mysql.html
mysql> INSTALL PLUGIN Deep_Thought SONAME 'psm_example.so';
Query OK, 0 rows affected (0.10 sec)
mysql> CREATE FUNCTION test.FooAnswer()
-> RETURNS TABLE(answer TEXT)
-> NO SQL LANGUAGE Deep_Thought EXTERNAL NAME 'compute';
Query OK, 0 rows affected (0.01 sec)
mysql> CREATE VIEW foobar AS SELECT * FROM TABLE(test.FooAnswer) AS wibble;
Query OK, 0 rows affected (0.01 sec)
mysql> SELECT * FROM foobar WHERE answer LIKE 'F%';
+-----------+
| answer |
+-----------+
| Forty-Two |
+-----------+
1 row in set (0.01 sec)
On Tue, Mar 10, 2015 at 1:45 PM, Sergei Golubchik
Hi, Justin!
On Mar 10, Justin Swanhart wrote:
I am not sure of the point of that mdev. First, arrays are not table functions. Arrays are data structures. A table function can certainly return all the items in an array data structure as rows (which would be part of #820) but that doesn't mean that a table function could replace
an
ARRAY data type. Arrays also have to be able to be passed to stored routines and stored in tables too, or they are virtually useless.
Yes, the subject says "UDF returning arrays/ result set", and the point is to have result set, not just an array.
Second, WL#820, which far precedes that mdev, adds real table functions without magic "pretend" storage engine as suggested in the later mdev. In any case, you can't return an array or table, from a UDF, without changing the UDF interface which will break other UDF. The UDF interface IS NOT VERSIONED.
Right. But MDEV-5199 doesn't need to use or extend existing UDF interface. It simply uses "UDF" to mean "user definable function" without implying that it has anything to do with existing UDFs.
wl#820 adds external stored procedures and doesn't modify the udf interface (UDF can rot) The mysql bug link I sent makes item functions internally pluggable, so they could support table functions as well and provide a replacement for UDF. Add an ARRAY data type and implement these patches (which are from Antony Curtis) and you'll get what you want. It would be a real shame to replace wl#820 work with some half-backed UDF that has not access to internals.
This is largely unrelated. This MDEV-5199 is about user functions that can return a table. Something like
SELECT * FROM t1, tf(15, NOW()) as t2 WHERE t1.a=t2.b;
So, it's about the server that can invoke a UDF in this context and retrieve many rows from the user function.
While wl#820 is about the language in which this user function is written.
Regards, Sergei