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[GeoNetwork opensource Developer website] #165: "unable to open resource main-db" returned by metadata.show and xml.iso19139 services - stalls server?

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[GeoNetwork opensource Developer website] #165: "unable to open resource main-db" returned by metadata.show and xml.iso19139 services - stalls server?

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#165: "unable to open resource main-db" returned by metadata.show and
xml.iso19139 services - stalls server?
---------------------+------------------------------------------------------
Reporter: simonp | Owner: [hidden email]
Type: defect | Status: new
Priority: major | Milestone: v2.4.1
Component: General | Version: v2.5.0
Keywords: |
---------------------+------------------------------------------------------
Reported by Heikki Doeleman:

________________________________________
From: James Wilson [[hidden email]]
Sent: Wednesday, 21 October 2009 3:02 AM
To: [hidden email]
Subject: Re: [GeoNetwork-devel] "unable to open resource main-db"

Heikki,

I'm also seeing this problem after doing repeated saves. I'm using oracle,
with pool size = 10 and reconnectTime=undefined. Problem is not easily
repeatable, but happens regularly.

Is this a problem with the connection pool running out of objects?

Reading the code, I'm somewhat confused as to how the connection pool is
supposed to work, and resources get released. By my reading, the only
place
connections get released is by calling close on connection pool object
(DbmsPool) with the resource (Dbms) as an argument, which unlocks the
resource.

However, in the code, this never seems to be done. The default pattern
seems
to be to get a new resource with

dbms = context.getResourceManager().open(Geonet.Res.MAIN_DB)

and then to leave the resource to go out of scope

Yours, mystified, and frustrated at not being able to track down the
error....

Anybody else got any ideas?

James

Heikki Doeleman wrote:
>
> hello lists,
>
> I'm seeing this error, every so often :
>
> **"unable to open resource main-db after 20attempts"
>
> This happens when you're using the editor for a bit. When it happens,
you
> must either restart GeoNetwork or wait a while (session timeout?).
>
> It started to happen for us after moving to Postgres and moving to a GN
> 2.4-based application.
>
> A search on Google shows that quite lots of GeoNetwork nodes have it.
> Moreover, from a WHO node that displays a stacktrace, it seems they have
> it
> when using MySQL, not Postgres (
>
http://209.85.229.132/search?q=cache:5Z0sxBf6fS8J:apps.who.int/geonetwork/srv/en/metadata.show%3Fid%3D74%26currTab%3Dsimple+%22unable+to+open+resource+
main-
db%22+%22Communications+link+failure+due+to+underlying+exception:%22&cd=1&hl=en&ct=clnk
> ).
>
> Does anybody know what to do to prevent this from ever happening ? My
JDBC
> settings in config.xml are poolSize=10, reconnectTime=undefined
> (defaulting
> to Jeeves).
>
>
> Thank you so much
>
> Kind regards
> Heikki Doeleman
>

--
Ticket URL: <http://trac.osgeo.org/geonetwork/ticket/165>
GeoNetwork opensource Developer website <http://trac.osgeo.org/geonetwork>
GeoNetwork opensource is a standards based, Free and Open Source catalog application to manage spatially referenced resources through the web. It provides powerful metadata editing and search functions as well as an embedded interactive web map viewer. This website contains information related to the development of the software.
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OSGeo

Re: [GeoNetwork opensource Developer website] #165: "unable to open resource main-db" returned by metadata.show and xml.iso19139 services - stalls server?

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#165: "unable to open resource main-db" returned by metadata.show and
xml.iso19139 services - stalls server?
----------------------+-----------------------------------------------------
Reporter: simonp | Owner: [hidden email]
Type: defect | Status: new
Priority: major | Milestone: v2.4.1
Component: General | Version: v2.5.0
Resolution: | Keywords:
----------------------+-----------------------------------------------------
Comment (by simonp):

Looking at Heikki's original message and references to stack traces in
google - its actually taking place in the services metadata.show and
iso19139.xml. I can reproduce it with curl and thumping the server with
lots of requests to the metadata.show service.

Seems that some code, somewhere was opening a Dbms resource but wasn't
going through the usual Jeeves clean up of Dbms resources (via commit on
success or rollback on exception) at the end of a service, hence the 10
Dbms connections in the pool would eventually end up locked and an
exception with message 'unable to open main-db after 20 attempts' would be
given. The code appears to be the timertask thread that is used to
increase popularity asynchronously in metadata.show (its also called by
iso19139.xml). One fix is to add:

context.getResourceManager().close();

as the last line of the try block in the run method of the
IncreasePopularityTask class in
src/org/fao/geonet/services/metadata/Show.java

I'm not sure this is good though as when thumping the server (albeit with
a somewhat unrealistic load) as described above, the thread that commits
the increase in popularity tends to overlap with other threads that
attempt to select from the Metadata table - the select threads fail
because of pending commits. Safest might be to remove the async popularity
update task and just run dm.increasePopularity(dbms, id); synchronously
(no exceptions there)?

Cheers,
Simon

--
Ticket URL: <http://trac.osgeo.org/geonetwork/ticket/165#comment:1>
GeoNetwork opensource Developer website <http://trac.osgeo.org/geonetwork>
GeoNetwork opensource is a standards based, Free and Open Source catalog application to manage spatially referenced resources through the web. It provides powerful metadata editing and search functions as well as an embedded interactive web map viewer. This website contains information related to the development of the software.
------------------------------------------------------------------------------
Come build with us! The BlackBerry(R) Developer Conference in SF, CA
is the only developer event you need to attend this year. Jumpstart your
developing skills, take BlackBerry mobile applications to market and stay
ahead of the curve. Join us from November 9 - 12, 2009. Register now!
http://p.sf.net/sfu/devconference
_______________________________________________
GeoNetwork-devel mailing list
[hidden email]
https://lists.sourceforge.net/lists/listinfo/geonetwork-devel
GeoNetwork OpenSource is maintained at http://sourceforge.net/projects/geonetwork

OSGeo

Re: [GeoNetwork opensource Developer website] #165: "unable to open resource main-db" returned by metadata.show and xml.iso19139 services - stalls server?

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