[PATCH] Fix quotation logic for unreserved keywords in window specifications - Mailing list pgsql-hackers

Hi hackers,

I was testing views with pg_dump/pg_restore and found a case where an unreserved keyword is not quoted correctly.

example:

-- Just a base table

CREATE TABLE t (v int);

INSERT INTO t VALUES (1), (2);

-- Create a view

CREATE VIEW v AS
SELECT count(*) OVER w2 FROM t
WINDOW "rows" AS (PARTITION BY v), w2 AS ("rows" ORDER BY v);

But the problem is, here, that quotation is gone.

-- Problem: Quotation is disappared

SELECT pg_get_viewdef('v');

                       pg_get_viewdef                        
-------------------------------------------------------------
  SELECT count(*) OVER w2 AS count                          +
    FROM t                                                  +
   WINDOW rows AS (PARTITION BY v), w2 AS (rows ORDER BY v);
(1 row)

-- If you use this for recovering the view above, You'll face this error.

 SELECT count(*) OVER w2 AS count
        FROM t
        WINDOW rows AS (PARTITION BY v), w2 AS (rows ORDER BY v);
ERROR:  syntax error at or near "ORDER"
LINE 3:  WINDOW rows AS (PARTITION BY v), w2 AS (rows ORDER BY v);

Fortunately, I found this comment in the gram.y:

It says:

 * If we see PARTITION, RANGE, ROWS or GROUPS as the first token after the '('
 * of a window_specification, we want the assumption to be that there is
 * no existing_window_name; but those keywords are unreserved and so could
 * be ColIds.

I think that assumption can be broken when inheritance is used across multiple window definitions.

I mean this: w2 AS ("rows" ORDER BY v)

Some comments for patch file:

The attached patch quotes the window name when it is a keyword in get_rule_windowspec().

Output for ordinary window names is unchanged. The window definition itself is a ColId so no change is needed there; only the refname is quoted.

I'd appreciate any feedback or suggestions...!!

Best regards...