Preventing or controlling runaway queries

[Eric E <whalesuit@xxxxxxxxx>]

Hi all,
   I've recently had a couple worrisome experiences with runaway 
queries in postgres 7.4 and 8.0, and I'm wondering what I can do to 
control or prevent these.  When I ran a query against a large table, I 
accidentally omitted mistyped a table name, and a table was 
automatically added, resulting in a massive result set that crash my 
postmaster instance.  I know that the automatic addition of missing 
tables to queries can be disabled, so I'm not so worried about that.

However, I am worried about generic queries being able to crash the 
entire server instance, which in my case occurs because the query 
process keeps allocating more memory until the machine is out of memory, 
then Linux' memory manager kills the process (I learned this latter part 
thanks to the list archives).  Is there some way to limit the amount of 
memory a single query process can use?  If it reaches that limit, what 
happens to the query?  What I'm looking for is a way to have the query 
be ended or suspended without the OS (Linux) killing the server 
process).  Does anyone had suggestions on how to accomplish this?

Thanks,

Eric