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Re: Re: [NOVICE] Re: re : PHP and persistent connections

From: Don Baccus <dhogaza(at)pacifier(dot)com>
To: ron(at)Opus1(dot)COM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL Hackers List <pgsql-hackers(at)postgresql(dot)org>
Cc: GH <grasshacker(at)over-yonder(dot)net>, pgsql-novice(at)postgresql(dot)org
Subject: Re: Re: [NOVICE] Re: re : PHP and persistent connections
Date: 2000-11-26 02:54:21
Message-ID: 3.0.1.32.20001125185421.01b066e0@mail.pacifier.com (view raw or flat)
Thread:
Lists: pgsql-hackerspgsql-novice
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(at)over-yonder(dot)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(at)pacifier(dot)com>
  Nature photos, on-line guides, Pacific Northwest
  Rare Bird Alert Service and other goodies at
  http://donb.photo.net.

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