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From: "Caldarale, Charles R" <Chuck.Caldarale@unisys.com>
To: Tomcat Users List <users@tomcat.apache.org>
Date: Sat, 26 Jan 2013 08:06:34 -0600
Subject: RE: [OT] Best way to log requests from a servlet and to a database?
Thread-Topic: [OT] Best way to log requests from a servlet and to a database?
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> From: Brian Braun [mailto:brianbraun@gmail.com]=20
> Subject: Re: Best way to log requests from a servlet and to a database?

(Marking this off-topic, since it has nothing to do with Tomcat.)

> My current method can hold about 3000 threads until memory collapses. I'm
> looking to replace this method with something more efficient in terms of
> RAM usage. Something like a buffer, where each item needs far less RAM th=
an
> the kind of threads I'm creating now. Then when it gets full I will use
> Amazon's queue as a failover mechanism.Any ideas?  :-)

Instead of using one additional thread per log entry, use just _one_ additi=
onal logging service thread.  When each request processing thread has prepa=
red the object representing the log entry to be made, that object should be=
 placed on a synchronized FIFO queue.  If the logging service thread is idl=
e, the request processing thread should mark the logging service thread as =
active and wake it up before unlocking the queue; if the logging service th=
read is already active, the request processing thread just unlocks the queu=
e after enqueuing its entry.  When the logging service thread wakes up, it =
must lock the queue, remove _all_ the entries currently on the queue, unloc=
k the queue, and send all the removed entries to the database in as few cal=
ls as possible.  Once that's done, the logging service thread relocks the q=
ueue, checks for any new arrivals and repeats as needed.  If no new arrival=
s, it marks itself as inactive, and goes to sleep on the queue.  No polling=
 required.

You can use the standard synchronization methods (wait(), notify(), etc.) f=
or all this (safest), or the newer but easier to abuse java.util.concurrent=
 operations.

 - Chuck


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