Thread

Dropped connection during COPY causes trouble

Tom Lane <tgl@sss.pgh.pa.us> — 1999-07-22T00:45:01Z

Don't kill a psql client that's in the middle of a COPY IN operation.

With current sources, the connected backend fails to quit, but instead
goes into an infinite loop writing
pq_recvbuf: unexpected EOF on client connection
to stderr over and over.

If you have postmaster stderr directed to a disk file, as I believe
is standard procedure, by and by the disk the postmaster logfile
is on fills up, and people start getting very unhappy...

I assume this is fairly easily fixed, but do not have a fix right this
instant.  It's probably my fault though --- I suppose it is an artifact
of the changes I made a couple months ago to prevent NOTICE messages
from coming out at inopportune times.  (If the bug were in pre-6.5
releases I'm sure we'd have heard about it before.)

Will produce a back-patch for 6.5 when I have it, but wanted to give
people a heads-up now.  Most embarrassing.

BTW, it occurs to me that the system ought to have provisions for
limiting the size of the logfile, rotating logfiles from time to
time, etc ... right now you cannot do those things easily except
by restarting the postmaster :-(.  Even without this bug, a determined
attacker could create a DOS attack by doing EXPLAIN VERBOSE enough
times to run the postmaster logfile up to full disk.  Bruce, I think
we need another TODO item:
  * prevent postmaster logfile from growing without bound

			regards, tom lane

Re: [BUGS] Dropped connection during COPY causes trouble

Bruce Momjian <maillist@candle.pha.pa.us> — 1999-07-22T01:08:41Z

> 
> BTW, it occurs to me that the system ought to have provisions for
> limiting the size of the logfile, rotating logfiles from time to
> time, etc ... right now you cannot do those things easily except
> by restarting the postmaster :-(.  Even without this bug, a determined
> attacker could create a DOS attack by doing EXPLAIN VERBOSE enough
> times to run the postmaster logfile up to full disk.  Bruce, I think
> we need another TODO item:
>   * prevent postmaster logfile from growing without bound

Not sure this really is a PostgreSQL issue.  Other OS systems have this
problem too.

-- 
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RE: [HACKERS] Re: [BUGS] Dropped connection during COPY causes t

Vince Vielhaber <vev@michvhf.com> — 1999-07-22T01:48:57Z

On 22-Jul-99 Bruce Momjian wrote:
>> 
>> BTW, it occurs to me that the system ought to have provisions for
>> limiting the size of the logfile, rotating logfiles from time to
>> time, etc ... right now you cannot do those things easily except
>> by restarting the postmaster :-(.  Even without this bug, a determined
>> attacker could create a DOS attack by doing EXPLAIN VERBOSE enough
>> times to run the postmaster logfile up to full disk.  Bruce, I think
>> we need another TODO item:
>>   * prevent postmaster logfile from growing without bound
> 
> Not sure this really is a PostgreSQL issue.  Other OS systems have this
> problem too.

I've seen these complaints on other lists for other programs (mail, news,
web, etc...).  IMO it's more of an administration issue than an OS issue
or even something for the program filling it.  The admin needs to know 
what's running on his/her system and how to handle the logs (and the 
rotating of) accordingly.

Vince.
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RE: [HACKERS] Re: [BUGS] Dropped connection during COPY causes t

Don Baccus <dhogaza@pacifier.com> — 1999-07-22T04:07:48Z

At 09:48 PM 7/21/99 -0400, Vince Vielhaber wrote:

>I've seen these complaints on other lists for other programs (mail, news,
>web, etc...).  IMO it's more of an administration issue than an OS issue
>or even something for the program filling it.  The admin needs to know 
>what's running on his/her system and how to handle the logs (and the 
>rotating of) accordingly.

Well, there are programs that allow automatic rotating of logs, of
course.  AOLserver - the webserver I use with Postgres - is one 
example.  I think I can limit the size of a log, too, but would
have to check.

It seems like a useful feature for any 24/7 service.

- Don Baccus, Portland OR <dhogaza@pacifier.com>
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