Re: [thredds] Severe errors on shutdown (TDS 4.2.6.)

• To: thredds@xxxxxxxxxxxxxxxx
• Subject: Re: [thredds] Severe errors on shutdown (TDS 4.2.6.)
• From: Ethan Davis <edavis@xxxxxxxxxxxxxxxx>
• Date: Mon, 18 Apr 2011 17:19:04 -0600

Hi Roy,

Yes, the TDS gets this type of messages on TDS shutdown when running
under Tomcat 6.0.24 or later. Tomcat looks for memory (thread) leaks
when web applications are stopped and tries to shut the threads down.
Tomcat evidently started detecting this particular type of thread
leakage in Tomcat 6.0.24 but proper shutdown of them isn't available
until Tomcat 7.0.6 [1]. It does not appear that these threads are leaked
except upon shutdown.

This could be an issue if you reload (stop/start) the TDS (or any other
web app) a number of times without restarting Tomcat. Because of this
and other issues, we recommend stop/starting Tomcat when possible (at
least occasionally) rather than stop/starting the TDS.

We haven't yet thoroughly tested the TDS on Tomcat 7 so we don't
recommend switching to Tomcat 7 yet.

Ethan

[1] http://wiki.apache.org/tomcat/MemoryLeakProtection#customThreadLocal

On 4/16/2011 5:03 PM, Roy Mendelssohn wrote:
> Hi All:
> 
> Running TDS 4.2.6. Had to do a bunch of start/stops to get the ncISO
> services and F-TDS running. On shutdown, I get a string of errors of the
> form:
> 
> SEVERE: The web application [/thredds] created a ThreadLocal with
> key of type [org.apache.log4j.helpers.ThreadLocalMap] (value
> [org.apache.log4j.helpers.ThreadLocalMap@612ef6]) and a value of type
> [java.util.Hashtable] (value [{startTime=1302990404971, userid=-,
> host=192.168.31.18, ident=-, ID=197, request="GET
> /thredds/wms/SODA/2.0.3?VERSION=1.3.0&SERVICE=WMS&REQUEST=GetMap&CRS=CRS:84&WIDTH=400&HEIGHT=200&LAYERS=temp&BBOX=-180.0,-75.25,180.0,89.25&TRANSPARENT=TRUE&STYLES=&FORMAT=image/png
> HTTP/1.1"}]) but failed to remove it when the web application was
> stopped. This is very likely to create a memory leak.
> 
> Thanks,
> 
> -Roy

• Follow-Ups:
  • Re: [thredds] Severe errors on shutdown (TDS 4.2.6.)
    • From: Tom Kunicki

• References:
  • [thredds] Severe errors on shutdown (TDS 4.2.6.)
    • From: Roy Mendelssohn