selection manager set iterators not synchronized, can fail with ConcurrentModificationException

[simonp]

Reported by James.Q.Wilson@…:

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)

[simonp]

Also apply to SelectionSearch, MassiveNewOwner and MassiveXslProcessing

Fixed in svn commit rev 5374