From my understanding, the JGroups backend can use static or automatic master, have you tried to use static master? I can see from Hibernate Search docs that automatic master election is [experimental and has some drawbacks|https://docs.jboss.org/hibernate/stable/search/reference/en-US/...]

From my understanding, the JGroups backend can use static or automatic master, have you tried to use static master? I can see from Hibernate Search docs that automatic master election is [experimental and has some drawbacks|https://docs.jboss.org/hibernate/stable/search/reference/en-US/...]

High concurrency : Infinispan Directory Provider: Lucene : Error loading metadata for index file ------------------------------------------------------------------------------------------------ Key: ISPN-8980 URL: https://issues.jboss.org/browse/ISPN-8980 Project: Infinispan Issue Type: Bug Components: Lucene Directory Affects Versions: 8.2.5.Final Reporter: Debashish Bharali Assignee: Gustavo Fernandes Priority: Critical Attachments: SysOutLogs.txt, neutrino-hibernate-search-worker-jgroups.xml, neutrino-hibernatesearch-infinispan.xml During high concurrency of action, we are getting *{color:red}'Error loading metadata for index file'{color}* even in *{color:red}Non-Clustered{color}* env. *Hibernate Search Indexes (Lucene Indexes) - 5.7.0.Final* *Infinispan - 8.2.5.Final* *infinispan-directory-provider-8.2.5.Final* *jgroups-3.6.7.Final* *Worker Backend : JGroups* *Worker Execution: Sync* *write_metadata_async: false (implicitly)* *Note:* Currently we are on Non-Clustered env. We are moving to Clustered Env within few days. On analyzing the code, and putting some additional SYSOUT loggers into FileListOperations and DirectoryImplementor classes, we have established the following points: # This is happening during high concurrency on non-clustered env. # One thread *'T1'* is deleting a segment and segment name *'SEG1'* from the *'FileListCacheKey'* list* stored in MetaDatacache*. # Concurrently, at the same time, another thread *'T2'* is looping through the FileList ['copy list' from MetadataCache - for -FileListCacheKey - provided by toArray method of *FileListOperations* (changes also being done in the corresponding original list by T1 thread) ]. # *'T2'* is calling open input method on each segment name - getting corresponding Metadata segment from *MetadataCache*. # However, for *'T2'*, the *'copy list'* still contains the name of segment *'SEG1'*. # So while looping through the list, *'T2'* tries to get Segment from MetadataCache for segment name *'SEG1'*. # But at this instant, *segment* corresponding to segment name *'SEG1'*, has been already removed from *MetadataCache* by *'T1'*. # This results in *'java.io.FileNotFoundException: Error loading metadata for index file'* for segment name *'SEG1'* # As mentioned earlier, this happens more often during high concurrency. *{color:red}On a standalone server (non-clustered), we are getting below error intermittently:{color}* Full Stack trace: 2018-03-19 17:29:11,938 ERROR [Hibernate Search sync consumer thread for index com.nucleus.integration.ws.server.globalcustomer.entity.GlobalCustomer] o.h.s.e.i.LogErrorHandler [LogErrorHandler.java:69] *{color:red}HSEARCH000058: Exception occurred java.io.FileNotFoundException: Error loading metadata for index file{color}*: M|segments_w6|com.nucleus.integration.ws.server.globalcustomer.entity.GlobalCustomer|-1 Primary Failure: Entity com.nucleus.integration.ws.server.globalcustomer.entity.GlobalCustomer Id 1649990024999813056 Work Type org.hibernate.search.backend.AddLuceneWork java.io.FileNotFoundException: Error loading metadata for index file: M|segments_w6|com.nucleus.integration.ws.server.globalcustomer.entity.GlobalCustomer|-1 at org.infinispan.lucene.impl.DirectoryImplementor.openInput(DirectoryImplementor.java:138) ~[infinispan-lucene-directory-8.2.5.Final.jar:8.2.5.Final] at org.infinispan.lucene.impl.DirectoryLucene.openInput(DirectoryLucene.java:102) ~[infinispan-lucene-directory-8.2.5.Final.jar:8.2.5.Final] at org.apache.lucene.store.Directory.openChecksumInput(Directory.java:109) ~[lucene-core-5.5.4.jar:5.5.4 31012120ebbd93744753eb37f1dbc5e654628291 - jpountz - 2017-02-08 19:08:03] at org.apache.lucene.index.SegmentInfos.readCommit(SegmentInfos.java:294) ~[lucene-core-5.5.4.jar:5.5.4 31012120ebbd93744753eb37f1dbc5e654628291 - jpountz - 2017-02-08 19:08:03] at org.apache.lucene.index.IndexFileDeleter.<init>(IndexFileDeleter.java:171) ~[lucene-core-5.5.4.jar:5.5.4 31012120ebbd93744753eb37f1dbc5e654628291 - jpountz - 2017-02-08 19:08:03] at org.apache.lucene.index.IndexWriter.<init>(IndexWriter.java:949) ~[lucene-core-5.5.4.jar:5.5.4 31012120ebbd93744753eb37f1dbc5e654628291 - jpountz - 2017-02-08 19:08:03] at org.hibernate.search.backend.impl.lucene.IndexWriterHolder.createNewIndexWriter(IndexWriterHolder.java:126) ~[hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.IndexWriterHolder.getIndexWriter(IndexWriterHolder.java:92) ~[hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.AbstractCommitPolicy.getIndexWriter(AbstractCommitPolicy.java:33) ~[hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.SharedIndexCommitPolicy.getIndexWriter(SharedIndexCommitPolicy.java:77) ~[hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.SharedIndexWorkspaceImpl.getIndexWriter(SharedIndexWorkspaceImpl.java:36) ~[hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.AbstractWorkspaceImpl.getIndexWriterDelegate(AbstractWorkspaceImpl.java:203) [hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.LuceneBackendQueueTask.applyUpdates(LuceneBackendQueueTask.java:81) [hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.LuceneBackendQueueTask.run(LuceneBackendQueueTask.java:46) [hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.SyncWorkProcessor$Consumer.applyChangesets(SyncWorkProcessor.java:165) [hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at org.hibernate.search.backend.impl.lucene.SyncWorkProcessor$Consumer.run(SyncWorkProcessor.java:151) [hibernate-search-engine-5.7.0.Final.jar:5.7.0.Final] at java.lang.Thread.run(Thread.java:785) [na:1.8.0-internal] *As per our understanding, this issue should not come in {color:red}'non-clustered'{color} env. Also it should not arise when worker execution is {color:red}'sync'{color}.* *We have debugged the code, and confirmed that the value for {color:red}'write_metadata_async'{color} is coming as 'false' only (as expected).*