Re: Re: [NOVICE] Re: re : PHP and persistent connections
Don Baccus <dhogaza@pacifier.com>
From: Don Baccus <dhogaza@pacifier.com>
To: ron@Opus1.COM, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers List <pgsql-hackers@postgresql.org>
Cc: GH <grasshacker@over-yonder.net>, pgsql-novice@postgresql.org
Date: 2000-11-26T02:54:21Z
Lists: pgsql-hackers
At 05:26 PM 11/25/00 -0700, Ron Chmara wrote: >Note: CC'd to Hackers, as this has wandered into deeper feature issues. > >Tom Lane wrote: >> GH <grasshacker@over-yonder.net> writes: >> > Do the "persistent-connected" Postgres backends ever timeout or die? >> No. A backend will sit patiently for the client to send it another >> query or close the connection. > >This does have an unfortunate denial-of-service implication, where >an attack can effectively suck up all available backends, and there's >no throttle, no timeout, no way of automatically dropping these.... > >However, the more likely possibility is similar to the problem that >we see in PHP's persistant connections.... a normally benign connection >is inactive, and yet it isn't dropped. If you have two of these created >every day, and you only have 16 backends, after 8 days you have a lockout. > >On a busy web site or another busy application, you can, of course, >exhaust 64 backends in a matter of minutes. Ugh...the more I read stuff like this the more I appreciate AOlserver's built-in database API which protects the application from any such problems altogether. The particular problem being described simply can't occur in this environment. - Don Baccus, Portland OR <dhogaza@pacifier.com> Nature photos, on-line guides, Pacific Northwest Rare Bird Alert Service and other goodies at http://donb.photo.net.