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Posted to oak-issues@jackrabbit.apache.org by "Thomas Mueller (JIRA)" <ji...@apache.org> on 2016/07/05 14:39:10 UTC
[jira] [Commented] (OAK-4538) IndexDefinition.createCodec class
loading deadlock
[ https://issues.apache.org/jira/browse/OAK-4538?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15362565#comment-15362565 ]
Thomas Mueller commented on OAK-4538:
-------------------------------------
Suggested patch (Oak 1.4):
{noformat}
--- src/main/java/org/apache/jackrabbit/oak/plugins/index/lucene/IndexDefinition.java (revision 1748577)
+++ src/main/java/org/apache/jackrabbit/oak/plugins/index/lucene/IndexDefinition.java (working copy)
@@ -1296,7 +1296,13 @@
String codecName = getOptionalValue(definition, LuceneIndexConstants.CODEC_NAME, null);
Codec codec = null;
if (codecName != null) {
+ // prevent LUCENE-6482
+ OakCodec ensureLucene46CodecLoaded = new OakCodec();
+ // to ensure the JVM doesn't optimize away object creation
+ // (probably not really needed; just to be save)
+ log.debug("Lucene46Codec is loaded: {}", ensureLucene46CodecLoaded);
codec = Codec.forName(codecName);
+ log.debug("Codec is loaded: {}", codecName);
} else if (fullTextEnabled) {
codec = new OakCodec();
}
{noformat}
> IndexDefinition.createCodec class loading deadlock
> --------------------------------------------------
>
> Key: OAK-4538
> URL: https://issues.apache.org/jira/browse/OAK-4538
> Project: Jackrabbit Oak
> Issue Type: Bug
> Components: lucene, query
> Reporter: Thomas Mueller
> Assignee: Thomas Mueller
>
> Sometimes, when initializing an Oak Lucene index, a class loading deadlock can occur. Unfortunately, no deadlock is reported by the JVM when creating a full thread dump, but the thread dump typically shows the threads below. The root cause seems to be LUCENE-6482, and the reason for that is described in http://ternarysearch.blogspot.it/2013/07/static-initialization-deadlock.html
> I have created a simple, reproducible test case, and found a simple workaround in Oak, which is to load the OakCodec before a custom codec. This ensures the class OakCodec, and all superclasses, are loaded before the static initializer of Codec is run. Test case see below (un-commenting the commented line will make it work, otherwise the test results in a deadlock most of the time).
> {noformat}
> java.lang.Thread.State: RUNNABLE
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.createCodec(IndexDefinition.java:1301)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.<init>(IndexDefinition.java:260)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.<init>(IndexDefinition.java:228)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexNode.open(IndexNode.java:48)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexTracker.findIndexNode(IndexTracker.java:179)
> - locked <0x00000007ff915448> (a org.apache.jackrabbit.oak.plugins.index.lucene.IndexTracker)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexTracker.acquireIndexNode(IndexTracker.java:154)
> at org.apache.jackrabbit.oak.plugins.index.lucene.LucenePropertyIndex.getPlans(LucenePropertyIndex.java:250)
> at org.apache.jackrabbit.oak.query.QueryImpl.getBestSelectorExecutionPlan(QueryImpl.java:1016)
> at org.apache.jackrabbit.oak.query.QueryImpl.getBestSelectorExecutionPlan(QueryImpl.java:949)
> at org.apache.jackrabbit.oak.query.ast.SelectorImpl.prepare(SelectorImpl.java:288)
> at org.apache.jackrabbit.oak.query.QueryImpl.prepare(QueryImpl.java:631)
> at org.apache.jackrabbit.oak.query.QueryEngineImpl.prepareAndSelect(QueryEngineImpl.java:298)
> at org.apache.jackrabbit.oak.query.QueryEngineImpl.executeQuery(QueryEngineImpl.java:273)
> at org.apache.jackrabbit.oak.query.QueryEngineImpl.executeQuery(QueryEngineImpl.java:233)
> at org.apache.jackrabbit.oak.plugins.identifier.IdentifierManager.resolveUUID(IdentifierManager.java:314)
> at org.apache.jackrabbit.oak.plugins.identifier.IdentifierManager.resolveUUID(IdentifierManager.java:308)
> at org.apache.jackrabbit.oak.plugins.identifier.IdentifierManager.resolveUUID(IdentifierManager.java:304)
> at org.apache.jackrabbit.oak.plugins.identifier.IdentifierManager.getTree(IdentifierManager.java:133)
> at org.apache.jackrabbit.oak.security.authentication.token.TokenProviderImpl.getTokenInfo(TokenProviderImpl.java:250)
> at org.apache.jackrabbit.oak.security.authentication.token.TokenAuthentication.validateCredentials(TokenAuthentication.java:81)
> "aysnc-index-update-fulltext-async" prio=5 tid=0x00007fe845e51800 nid=0xb407 in Object.wait() [0x0000700005f2f000]
> java.lang.Thread.State: RUNNABLE
> at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
> at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
> at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
> at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
> at java.lang.Class.newInstance(Class.java:379)
> at org.apache.lucene.util.NamedSPILoader.reload(NamedSPILoader.java:67)
> - locked <0x00000007d2ba9120> (a org.apache.lucene.util.NamedSPILoader)
> at org.apache.lucene.util.NamedSPILoader.<init>(NamedSPILoader.java:45)
> at org.apache.lucene.util.NamedSPILoader.<init>(NamedSPILoader.java:37)
> at org.apache.lucene.codecs.Codec.<clinit>(Codec.java:41)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.createCodec(IndexDefinition.java:1299)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.<init>(IndexDefinition.java:260)
> at org.apache.jackrabbit.oak.plugins.index.lucene.IndexDefinition.<init>(IndexDefinition.java:224)
> at org.apache.jackrabbit.oak.plugins.index.lucene.LuceneIndexEditorContext.<init>(LuceneIndexEditorContext.java:170)
> at org.apache.jackrabbit.oak.plugins.index.lucene.LuceneIndexEditor.<init>(LuceneIndexEditor.java:132)
> at org.apache.jackrabbit.oak.plugins.index.lucene.LuceneIndexEditorProvider.getIndexEditor(LuceneIndexEditorProvider.java:72)
> at org.apache.jackrabbit.oak.plugins.index.CompositeIndexEditorProvider.getIndexEditor(CompositeIndexEditorProvider.java:74)
> at org.apache.jackrabbit.oak.spi.whiteboard.WhiteboardIndexEditorProvider.getIndexEditor(WhiteboardIndexEditorProvider.java:52)
> at org.apache.jackrabbit.oak.plugins.index.IndexUpdate.collectIndexEditors(IndexUpdate.java:201)
> at org.apache.jackrabbit.oak.plugins.index.IndexUpdate.enter(IndexUpdate.java:144)
> at org.apache.jackrabbit.oak.spi.commit.VisibleEditor.enter(VisibleEditor.java:57)
> at org.apache.jackrabbit.oak.spi.commit.EditorDiff.process(EditorDiff.java:49)
> at org.apache.jackrabbit.oak.plugins.index.AsyncIndexUpdate.updateIndex(AsyncIndexUpdate.java:510)
> at org.apache.jackrabbit.oak.plugins.index.AsyncIndexUpdate.runWhenPermitted(AsyncIndexUpdate.java:439)
> {noformat}
> Test case:
> {noformat}
> public class StaticInitDeadlock {
> public static class Codec {
> static {
> debug("<clinit>");
> forName("OtherCodec");
> forName("OakCodec");
> debug("<clinit> done");
> }
> static Codec forName(String name) {
> debug("Codec.forName(" + name + ")");
> try {
> return (Codec) Class.forName("StaticInitDeadlock$" + name)
> .newInstance();
> } catch (Exception e) {
> e.printStackTrace();
> return null;
> }
> }
> }
> static class OtherCodec extends Codec {
> static {
> debug("OtherCodec <clinit>");
> }
> }
> static class OakCodec extends Codec {
> static {
> debug("OakCodec <clinit>");
> }
> }
> static void createCodec(String codecName) {
> debug("createCodec (" + codecName + ")");
> if (codecName != null) {
> // new OakCodec();
> Codec.forName(codecName);
> } else {
> new OakCodec();
> }
> }
> public static void main(String[] args) throws InterruptedException {
> Thread thread = new Thread("Thread 2") {
> @Override
> public void run() {
> debug("loading other codec...");
> createCodec("OtherCodec");
> debug("loading other codec done!");
> }
> };
> thread.start();
> Thread.currentThread().setName("Thread 1");
> debug("loading default (oak) codec...");
> createCodec(null);
> debug("joining thread...");
> thread.join();
> debug("done!");
> }
> static void debug(String msg) {
> Thread t = Thread.currentThread();
> StackTraceElement[] st = t.getStackTrace();
> int depth = st.length;
> String indent = new String(new char[depth]).replace("\0", " ");
> System.out.println(t.getName() + ": " + indent + st[2] + " " + msg);
> }
> }
> {noformat}
> Output when deadlocked:
> {noformat}
> Thread 2: StaticInitDeadlock$1.run(StaticInitDeadlock.java:56) loading other codec...
> Thread 1: StaticInitDeadlock.main(StaticInitDeadlock.java:63) loading default (oak) codec...
> Thread 2: StaticInitDeadlock.createCodec(StaticInitDeadlock.java:43) createCodec (OtherCodec)
> Thread 1: StaticInitDeadlock.createCodec(StaticInitDeadlock.java:43) createCodec (null)
> Thread 2: StaticInitDeadlock$Codec.<clinit>(StaticInitDeadlock.java:11) <clinit>
> Thread 2: StaticInitDeadlock$Codec.forName(StaticInitDeadlock.java:18) Codec.forName(OtherCodec)
> Thread 2: StaticInitDeadlock$OtherCodec.<clinit>(StaticInitDeadlock.java:32) OtherCodec <clinit>
> Thread 2: StaticInitDeadlock$Codec.forName(StaticInitDeadlock.java:18) Codec.forName(OakCodec)
> {noformat}
> Output without deadlock:
> {noformat}
> Thread 1: StaticInitDeadlock.main(StaticInitDeadlock.java:63) loading default (oak) codec...
> Thread 2: StaticInitDeadlock$1.run(StaticInitDeadlock.java:56) loading other codec...
> Thread 1: StaticInitDeadlock.createCodec(StaticInitDeadlock.java:43) createCodec (null)
> Thread 2: StaticInitDeadlock.createCodec(StaticInitDeadlock.java:43) createCodec (OtherCodec)
> Thread 1: StaticInitDeadlock$Codec.<clinit>(StaticInitDeadlock.java:11) <clinit>
> Thread 1: StaticInitDeadlock$Codec.forName(StaticInitDeadlock.java:18) Codec.forName(OtherCodec)
> Thread 1: StaticInitDeadlock$OtherCodec.<clinit>(StaticInitDeadlock.java:32) OtherCodec <clinit>
> Thread 1: StaticInitDeadlock$Codec.forName(StaticInitDeadlock.java:18) Codec.forName(OakCodec)
> Thread 1: StaticInitDeadlock$Codec.<clinit>(StaticInitDeadlock.java:14) <clinit> done
> Thread 1: StaticInitDeadlock$OakCodec.<clinit>(StaticInitDeadlock.java:38) OakCodec <clinit>
> Thread 1: StaticInitDeadlock.main(StaticInitDeadlock.java:65) joining thread...
> Thread 2: StaticInitDeadlock$Codec.forName(StaticInitDeadlock.java:18) Codec.forName(OtherCodec)
> Thread 2: StaticInitDeadlock$1.run(StaticInitDeadlock.java:58) loading other codec done!
> Thread 1: StaticInitDeadlock.main(StaticInitDeadlock.java:67) done!
> {noformat}
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