[GeoNetwork-devel] Geonetworks concurrency errors

[James W. <jam...@go...>]

Hi,

I'm discovering more concurrency errors under load in geonetworks. BTW -
thanks for CSW fix for error I reported earlier in week.

The errors are for geonetworks 2_4_1 in Tomcat 6.20 with 1000 iso records
loaded:

- Massive Delete fails with java.util.ConcurrentModificationException - see
stack trace below. This results in inconsistency between lucene index and
database. Lucene index drops records up to point at which exception occurs.
Since commit is never done in database, data still exists, and can be
recovered by rebuilding lucene index.
- MassiveUpdatePriviledges fails with
java.util.ConcurrentModificationException - see stack trace below
- MassiveUpdateCategories - got no stack trace recorded for this one.

Problem seems to be with HashSet declared in SelectionManager. These are
wrapped as  synchronizedSet, which requires all iterators to be in
synchronized blocks (according to Java doc).

Iterators over this map in MassiveDelete / etc are not synchronized.
Explicitly synchronizing the iterators when these sets are accessed seems to
fix the concurrency problems:

eg

synchronized(sm.getSelection("metadata")) {

        // use iterator here
}

Regards

James

Stack traces:

First the massive delete:


88562 [34658350@qtp0-6] ERROR jeeves.service  - Exception when executing
servic
e
788562 [34658350@qtp0-6] ERROR jeeves.service  -  (C) Exc :
java.util.Concurrent
ModificationException
788562 [34658350@qtp0-6] DEBUG jeeves.service  - Raised exception while
executin
g service
<error id="error">
  <message />
  <class>ConcurrentModificationException</class>
  <stack>
    <at class="java.util.HashMap$HashIterator" file="HashMap.java"
line="921" me
thod="nextEntry" />
    <at class="java.util.HashMap$KeyIterator" file="HashMap.java" line="956"
met
hod="next" />
    <at class="org.fao.geonet.services.metadata.MassiveDelete"
file="MassiveDele
te.java" line="87" method="exec" />
    <at class="jeeves.server.dispatchers.ServiceInfo"
file="ServiceInfo.java" li
ne="238" method="execService" />
    <at class="jeeves.server.dispatchers.ServiceInfo"
file="ServiceInfo.java" li
ne="141" method="execServices" />
    <at class="jeeves.server.dispatchers.ServiceManager"
file="ServiceManager.ja
va" line="377" method="dispatch" />
    <at class="jeeves.server.JeevesEngine" file="JeevesEngine.java"
line="621" m
ethod="dispatch" />
    <at class="jeeves.server.sources.http.JeevesServlet"
file="JeevesServlet.jav
a" line="174" method="execute" />
    <at class="jeeves.server.sources.http.JeevesServlet"
file="JeevesServlet.jav
a" line="89" method="doGet" />
    <at class="javax.servlet.http.HttpServlet" file="HttpServlet.java"
line="707
" method="service" />
  </stack>
  <request>
    <language>en</language>
    <service>metadata.massive.delete</service>
  </request>
</error>

Then the massive Privs:

1454281 [http-8080-3] ERROR jeeves.service  - Exception when executing
service
1454281 [http-8080-3] ERROR jeeves.service  -  (C) Exc :
java.util.ConcurrentMod
ificationException
java.util.ConcurrentModificationException
        at java.util.HashMap$HashIterator.nextEntry(HashMap.java:921)
        at java.util.HashMap$KeyIterator.next(HashMap.java:956)
        at
org.fao.geonet.services.metadata.MassiveUpdatePrivileges.exec(Massive
UpdatePrivileges.java:85)
        at
jeeves.server.dispatchers.ServiceInfo.execService(ServiceInfo.java:24
4)
        at
jeeves.server.dispatchers.ServiceInfo.execServices(ServiceInfo.java:1
41)
        at
jeeves.server.dispatchers.ServiceManager.dispatch(ServiceManager.java
:377)
        at jeeves.server.JeevesEngine.dispatch(JeevesEngine.java:621)
        at
jeeves.server.sources.http.JeevesServlet.execute(JeevesServlet.java:1
74)
        at
jeeves.server.sources.http.JeevesServlet.doGet(JeevesServlet.java:89)

        at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)
        at
org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(Appl
icationFilterChain.java:290)
        at
org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationF
ilterChain.java:206)
        at
org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperV
alve.java:233)
        at
org.apache.catalina.core.StandardContextValve.invoke(StandardContextV
alve.java:191)
        at
org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.j
ava:128)
        at
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.j
ava:102)
        at
org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineVal
ve.java:109)
        at
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.jav
a:293)
        at
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java
:849)
        at
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.proce
ss(Http11Protocol.java:583)
        at
org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:45
4)
        at java.lang.Thread.run(Thread.java:619)