Crash caused by CHECK on child

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============================================================================
POSTGRESQL BUG REPORT TEMPLATE
============================================================================

Your name : Kevin Way
Your email address : kevin(dot)way(at)overtone(dot)org

System Configuration
---------------------
Architecture (example: Intel Pentium) : Intel Pentium III

Operating System (example: Linux 2.0.26 ELF) : FreeBSD 4.4

PostgreSQL version (example: PostgreSQL-7.1.3): PostgreSQL-7.1.3

Compiler used (example: gcc 2.95.2) : gcc 2.95.3

Please enter a FULL description of your problem:
------------------------------------------------

I get the error:

psql:fuck.sql:176: pqReadData() -- backend closed the channel unexpectedly.
This probably means the backend terminated abnormally
before or while processing the request.

while executing PL/pgSQL, called by a rule which gets
called when I touch the itemvote table from the below example.

Please describe a way to repeat the problem. Please try to provide a
concise reproducible example, if at all possible:
----------------------------------------------------------------------

The below will error on the last two lines (right after

CREATE SEQUENCE node_id_seq;

CREATE TABLE node (
node_id INT4 UNIQUE NOT NULL DEFAULT nextval('node_id_seq'),
name TEXT NOT NULL,
nays INT4 NOT NULL DEFAULT 0
CHECK ( nays >= 0 ),
yays INT4 NOT NULL DEFAULT 0,
CHECK ( yays >= 0 ),
rating INT2 NOT NULL DEFAULT 50
CHECK ( rating >= 0 AND rating <= 100 ),
PRIMARY KEY (node_id)
);

CREATE TABLE users (
node_id INT4 UNIQUE NOT NULL,
email TEXT NOT NULL,
realname TEXT NOT NULL,
pass_hash VARCHAR(32) NOT NULL,
lastlog TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
logged_in INT2 NOT NULL DEFAULT 0
CHECK (logged_in = 0 OR logged_in = 1)
) INHERITS (node);

CREATE TABLE item (
node_id INT4 UNIQUE NOT NULL,
creator_id INT4 NOT NULL
REFERENCES users (node_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
reason TEXT NOT NULL
) INHERITS (node);

CREATE TABLE itemvote (
vote_date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
target_id INT4 NOT NULL
REFERENCES item (node_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
user_id INT4 NOT NULL
REFERENCES users (node_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
nays INT2 NOT NULL
CHECK (nays = 0 OR nays = 1),

PRIMARY KEY (user_id, target_id)
);

CREATE TABLE uservote (
vote_date TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
target_id INT4 NOT NULL
REFERENCES users (node_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
user_id INT4 NOT NULL
REFERENCES users (node_id)
ON DELETE CASCADE
ON UPDATE CASCADE,
nays INT2 NOT NULL
CHECK (nays = 0 OR nays = 1),

PRIMARY KEY (user_id, target_id)
);

-- modifies an items nays/yays count totals as appropriate
-- first arg: item number
-- second arg: 1 or 0, nays or yays.
-- third arg: 1 or 0, add a vote, or remove a vote
CREATE FUNCTION mod_node_vote_count (INT4, INT2, INT2) RETURNS INT2 AS '
DECLARE
node_num ALIAS for $1;
nay_status ALIAS for $2;
add ALIAS for $3;

nay_tot INT4 NOT NULL DEFAULT 0;
yay_tot INT4 NOT NULL DEFAULT 0;
BEGIN
IF add = 1
THEN
IF nay_status = 1
THEN
UPDATE node SET nays = nays + 1 WHERE node_id = node_num;
ELSE
UPDATE node SET yays = yays + 1 WHERE node_id = node_num;
END IF;
ELSE
IF nay_status = 1
THEN
UPDATE node SET nays = nays - 1 WHERE node_id = node_num;
ELSE
UPDATE node SET yays = yays - 1 WHERE node_id = node_num;
END IF;
END IF;
SELECT nays INTO nay_tot FROM node WHERE node_id = node_num;
SELECT yays INTO yay_tot FROM node WHERE node_id = node_num;

IF nay_tot + yay_tot != 0
THEN
UPDATE node SET rating = CEIL( (yay_tot * 100)/(yay_tot + nay_tot) ) WHERE node_id = node_num;
ELSE
UPDATE node SET rating = 50 WHERE node_id = node_num;
END IF;

RETURN 1;
END;
' LANGUAGE 'plpgsql';

------------------------------------------------------------------------
-- vote totalling rules

-- vote insertion
CREATE RULE itemvote_insert_item_inc AS
ON INSERT TO itemvote DO
SELECT mod_node_vote_count(NEW.target_id, NEW.nays, 1);

CREATE RULE uservote_insert_item_inc AS
ON INSERT TO uservote DO
SELECT mod_node_vote_count(NEW.target_id, NEW.nays, 1);

-- vote deletion
CREATE RULE itemvote_delete_item_dec AS
ON DELETE TO itemvote DO
SELECT mod_node_vote_count(OLD.target_id, OLD.nays, 0);

CREATE RULE uservote_delete_item_dec AS
ON DELETE TO uservote DO
SELECT mod_node_vote_count(OLD.target_id, OLD.nays, 0);

-- vote updates
CREATE RULE itemvote_update_item_mod AS
ON UPDATE TO itemvote WHERE OLD.nays != NEW.nays DO
(SELECT mod_node_vote_count(OLD.target_id, OLD.nays, 1);
SELECT mod_node_vote_count(NEW.target_id, NEW.nays, 0););

CREATE RULE uservote_update_item_mod AS
ON UPDATE TO uservote WHERE OLD.nays != NEW.nays DO
(SELECT mod_node_vote_count(OLD.target_id, OLD.nays, 1);
SELECT mod_node_vote_count(NEW.target_id, NEW.nays, 0););

-- users
INSERT INTO users (name, pass_hash, realname, email) VALUES ('mosch', 'dafe001b7733b0f3236aa95e00f8ed88', 'Kevin', 'monica(at)whitehouse(dot)gov');
INSERT INTO users (name, pass_hash, realname, email) VALUES ('Wakko', 'c6ef90fcf92bf703c3cc79a679c192a3', 'Alex', 'wakko(at)bitey(dot)net');

-- items
INSERT INTO item (name, creator_id, reason) VALUES ('slashdot.org', 2, 'Because it\'s a pile of turd.');
INSERT INTO item (name, creator_id, reason) VALUES ('Yahoo!', 2, 'Because it\'s ugly.');
INSERT INTO item (name, creator_id, reason) VALUES ('memepool', 1, 'Because it\'s phat phat phat phat phat.');
INSERT INTO item (name, creator_id, reason) VALUES ('blow!!??!!', 1, 'this record nays nays nays');

-- item votes
INSERT INTO itemvote (target_id, user_id, nays) VALUES (3, 1, 1);
INSERT INTO itemvote (target_id, user_id, nays) VALUES (4, 1, 0);
INSERT INTO itemvote (target_id, user_id, nays) VALUES (5, 2, 1);

-- user votes XXX FIXME BugBug Postgres crashes here!
INSERT INTO uservote (target_id, user_id, nays) VALUES (2, 1, 0);
INSERT INTO uservote (target_id, user_id, nays) VALUES (1, 2, 1);

If you know how this problem might be fixed, list the solution below:
---------------------------------------------------------------------

Baldvin posted this greatly simplified test case, which also
crashes the server without even using PL/pgSQL on pgsql-sql.

-- Hi Kevin, and everyone!
--
-- I don't think that I only found a minor bug compared to
-- the other you wrote in your last letter: the backend crash
-- is caused by the same CHECK constraint in the child table.
--
-- However, for you without time to analyzing Kevin's huge
-- scheme, here is the very simplified, crash-causing script.
--
------------------------------------

drop table child;
drop table ancestor;

create table ancestor (
node_id int4,
a int4
);

create table child (
b int4 NOT NULL DEFAULT 0 ,
c int4 not null default 3,
CHECK ( child.b = 0 OR child.b = 1 )
) inherits (ancestor);

insert into ancestor values (3,4);
insert into child (node_id, a, b) values (5,6,1);

update ancestor set a=8 where node_id=5;

---------------------------------
--
-- I am hunting it, but I have to learn all what this query-executing
-- about, so probably it takes uncomparable longer for me than for
-- a developer.
--
-- Regards,
-- Baldvin
--

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