[BUGS] BUG #6185: Segmentation fault with NULL string columns
The following bug has been logged online:
Bug reference: 6185
Logged by: Isaac Jurado
Email address: ijur...@econcept.es
PostgreSQL version: 8.4.8
Operating system: Ubuntu 10.04.03 LTS (x86_64)
Description:Segmentation fault with NULL string columns
Details:
Here's the script to make it fail:
CREATE DATABASE killme;
\c killme
CREATE FUNCTION to_ascii(bytea, name) RETURNS text AS 'to_ascii_encname'
LANGUAGE internal;
CREATE TABLE mytable (id INTEGER PRIMARY KEY, mytext TEXT);
INSERT INTO mytable (id, mytext) VALUES (1, '');
SELECT * FROM mytable WHERE to_ascii(convert_to(mytext, 'latin1'), 'latin1')
= to_ascii(convert_to('nicetry', 'latin1'), 'latin1');
UPDATE mytable SET mytext=NULL WHERE id=1;
SELECT * FROM mytable WHERE to_ascii(convert_to(mytext, 'latin1'), 'latin1')
= to_ascii(convert_to('nicetry', 'latin1'), 'latin1');
After the second query, the database server segfaults. Note that it only
fails for NULL values. The to_ascii/convert_to combination is a recipe for
diacritics elimination found on a PostgreSQL forum.
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Re: [BUGS] BUG #6185: Segmentation fault with NULL string columns
On Tue, Aug 30, 2011 at 8:21 PM, Heikki Linnakangas wrote: > > to_ascii_encname is marked as STRICT, which means that it returns NULL > on NULL input, without ever calling the underlying C function. The > "to_ascii" function that you created is not marked as STRICT, so the > to_ascii_encname C function is called on NULL input. It's not prepared > for that, and crashes, because it's not supposed to be called on NULL > input. I figured that 5 minutes after reporting. I tried to sent a reply email but it seems it didn't arrive. Thanks anyway. > Why do you create your own 'internal' language function like that in > the first place? Just use the existing to_ascii function. The default to_ascii expects a string as a first argument. As our DB encoding is UTF8 we need to filter everything through convert_to(..., 'LATIN1'). Because convert_to function returns a "bytea" type, we cannot use to_ascii in vanilla flavour. We are not too fond with the PostgreSQL specifics (although the explicit ::text cast didn't work), so we found that function definition on a wiki and it worked. But now, unless you know a more correct way to do it, it works like a charm by appending "STRICT" to the function definition. Best regards and sorry for the noise. -- Isaac Jurado Internet Busines Solutions eConcept -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
Re: [BUGS] BUG #6185: Segmentation fault with NULL string columns
On Tue, Aug 30, 2011 at 8:22 PM, Alvaro Herrera wrote: > > Seems you neglected to mark the function STRICT. Yes, that was it. Sorry for the invalid bug report. Best regards. -- Isaac Jurado Internet Busines Solutions eConcept -- Sent via pgsql-bugs mailing list (pgsql-bugs@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-bugs
