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Andy Seaborne commented on JENA-1302: ------------------------------------- Update from my side: I have written a java-based test driver that does not cause the build up of WAIT by using a more managed set of reused persistent connections. It does exhibit the lockup. It is caused by the journal overload code being invoked which takes a while to happen. The code is taking locks in the wrong order and this causes a deadlock then then builds up. > Intermittent Lucene prepareCommit exception during heavy read/write load > ------------------------------------------------------------------------ > > Key: JENA-1302 > URL: https://issues.apache.org/jira/browse/JENA-1302 > Project: Apache Jena > Issue Type: Bug > Components: Fuseki, TDB, Text > Affects Versions: Jena 3.3.0 > Environment: CentOS 7.3 inside VM, 2 cores, OpenJDK 1.8.0_121 > (64-bit), 1GB JVM heap, Fuseki running as service > Reporter: Vilnis Termanis (Iotic Labs) > Assignee: Andy Seaborne > Fix For: Jena 3.3.0 > > Attachments: netstat.log, prepareCommit_error.tgz, > visualvm_thread_dump.log > > > (*Note*: Could not add Fuseki 2.6.0 as affected version although I assume > this is a TDB/text rather than Fuseki-related issue.) > *Steps:* > # Start with plain Fuseki + given configuration (TDB store + lucene text > indexing) > # Import 1k.ttl > # Run lockup.py (same host, mix of multiple parallel updates & single select) > *Result:* > Every now and again one of the update queries fails with a 500 server error > which is logged as: > {{DatasetGraphText ERROR Exception in prepareCommit: prepareCommit was > already called with no corresponding call to commit}} > *Notes:* > - Not reproducible without fix for JENA-1296 (and discovered during fix > verification for said issue) > - Run with > [apache-jena-fuseki-2.6.0-20170228.233930-10.tar.gz|https://repository.apache.org/content/repositories/snapshots/org/apache/jena/apache-jena-fuseki/2.6.0-SNAPSHOT/apache-jena-fuseki-2.6.0-20170228.233930-10.tar.gz] > - From cold-start of Fuseki, occurs within 30s of script run > - Supplied test script required Python 3, {{rdflib>=4.2.2}} & > {{SPARQLWrapper>=1.8.0}} -- This message was sent by Atlassian JIRA (v6.3.15#6346)