8.4.0 data loss / HOT-related bug - Mailing list pgsql-bugs

From Radoslaw Zielinski
Subject 8.4.0 data loss / HOT-related bug
Date
Msg-id 20090821150436.GA5835@bzium
Whole thread Raw
Responses Re: 8.4.0 data loss / HOT-related bug
Re: 8.4.0 data loss / HOT-related bug
List pgsql-bugs
Hello,

8.4.0 installation on i686 modern Linux, a simple production app with ~4
users entering data; normalised, no weird stuff happening there.  Recently:

  ERROR:  missing chunk number 0 for toast value 120741 in pg_toast_29644

This table has table_log and a "before update" trigger setting
"NEW.last_modified = now()".  The broken toast is a HTML blob, stored in
a "text" column.

This particular row currently has last_modified="2009-08-11", but table_log
says it has been updated on "2009-08-12" -- so, data loss.

Please see the attachment for the xmin,xmax,cmin,cmax,ctid values of
these rows.  Andrew Gireth has asked for the hexdump of page 539 of the
"promocje" table: http://radek.cc/promocje.hexdump


About a week after I've upgraded to 8.4, the users of this application
have started to complain, that some rows are disappearing.

--
Radosław Zieliński <radek@pld-linux.org>

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