The following bug has been logged online:

Bug reference: 2112
Logged by: Jim Dew
Email address: jdew@yggdrasil.ca
PostgreSQL version: 8.1.0
Operating system: OpenBSD
Description: query kills db thread
Details:

Stumbled upon a (broken) query that causes the 8.1.0 thread handling the
query to die:

select foo from (select null) as foo

Now, this query just produces an error on 8.0.3

8.1.0:

Welcome to psql 8.1.0, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

suth=# select foo from (select null) as foo;
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: Failed.
!>


8.0.3:
Welcome to psql 8.0.3, the PostgreSQL interactive terminal.

Type: \copyright for distribution terms
\h for help with SQL commands
\? for help with psql commands
\g or terminate with semicolon to execute query
\q to quit

suth=# select foo from (select null) as foo;
ERROR: subquery foo does not have attribute 0
suth=#

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