Re: [geomesa-users] Accumulo tablet-servers dying when accessing table v

["Barnhart, Bob M." <ROBERT.M.BARNHART@xxxxxxxxxx>]

Thanks for responding Chris.

The query is identical to the ones we've used, except for the SERVER IP address.

I have examined the "tserver" logs and nothing really pops out except for a "failure during memory compaction". I'm not even positive that this was THE fatal error when the tserver terminates. 

This problem is really hard because it is not easily reproduced. Things work sometimes, but fail unpredictably. It may be exacerbated by the fact that we're running Zookeeper/Hadoop/Accumulo+GeoMesa/GeoServer and possibly Storm as well on an RHEL Server 6.5 VM with only 16GB of "ram".

-----Original Message-----
From: geomesa-users-bounces@xxxxxxxxxxxxxxxx [mailto:geomesa-users-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Chris Eichelberger
Sent: Friday, December 19, 2014 8:18 AM
To: geomesa-users@xxxxxxxxxxxxxxxx
Subject: Re: [geomesa-users] Accumulo tablet-servers dying when accessing table via GeoServer using GeoMesa Plugin

Bob,

I have not seen this type of behavior before, but I recommend reading through the logs on one of the tablet-servers that fails.  

Out of curiosity, were there geographic, time, or attribute constraints on your query that you left out for brevity in your note?

Best of luck!

Sincerely,
  -- Chris


On Thu, 2014-12-18 at 23:39 +0000, Barnhart, Bob M. wrote:
> Our web-application uses GoogleEarth technology and has the ability to 
> request from Accumulo (via GeoServer using the GeoMesa Accumulo
> plugin) geospatial feature-data that has been ingested using GeoMesa.
> Once a user has zoomed into a particular area of the map, the 
> web-application uses AJAX to issue an HTTP request (such as the
> following) in order to bring back meta-data (in this case for
> “Full-Motion-Videos”) for any “features” that lie within the visible 
> map area:
> 
>  
> 
> http://SERVER:8080/geoserver/geomesa/ows?service=WFS&version=1.0.0&req
> uest=GetFeature&typeName=geomesa:fmv&outputFormat=application/json
> 
>  
> 
> Our web-application (asynchronously) submits such URL requests using 
> AJAX. The problem is that the request USUALLY (though not always) 
> fails and “hangs” with the side-effect that the Accumulo Table-Server 
> process will have terminated (possibly due to a memory-compaction 
> error). At this point it is not possible to access Accumulo via 
> GeoServer/GeoMesa-Plugin until the Zookeeper/Hadoop/Accumulo/GeoServer
> stack is restarted.
> 
>  
> 
> However, if I manually send this request to GeoServer using the 
> following wget(1) command, everything works fine:
> 
>  
> 
> wget -t 1 -O /tmp/gs-fmv.json
> http://SERVER:8080/geoserver/geomesa/ows?service=WFS&version=1.0.0&req
> uest=GetFeature&typeName=geomesa:fmv&outputFormat=application/json
> 
>  
> 
> I seem to be able to submit such requests at any frequency, even 
> submitting multiple concurrent requests, and experience no such 
> problems with the Accumulo Tablet Servers dying.
> 
>  
> 
> At this point, we’re stymied as to what might be happening and hoped 
> that perhaps one of you had seen some similar behavior or might have a 
> theory about what is happening, or even suggestions about how to debug 
> this.
> 
>  
> 
> FYI, we have been running the following software versions in our 
> “data-stack” since our work with GeoMesa/Accumulo technology began 
> April/May 2014:
> 
>  
> 
> accumulo-1.5.1
> 
> geomesa 1.0.0
> 
> geoserver-2.5
> 
> /webapps/geoserver/WEB-INF/lib/geomesa-plugin-1.0.0-SNAPSHOT-geoserver
> -plugin.jar
> 
> /webapps/geoserver/WEB-INF/lib/geomesa-core-1.0.0-SNAPSHOT.jar
> 
> hadoop-2.4.0
> 
> zookeeper-3.4.6
> 
>  
> 
> We would appreciate any help or insight you might be able to provide.
> 
>  
> 
> Bob Barnhart
> 
> Chief Systems Engineer | 858 826 5596 (Office) | 619 972 9489 (Mobile)
> | Robert.M.Barnhart@xxxxxxxxxx
> 
>  
> 
>  
> 
>  
> 
> 
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