[SOLR-6146] Leak in CloudSolrServer causing "Too many open files"

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 4.7
• Fix Version/s: 4.9, 6.0
• Component/s: clients - java, SolrCloud
• Labels: solrcloud solrj
• Assignee: Shalin Shekhar Mangar
• Reporter: Jessica Cheng Mallet
• Created: 05/Jun/14 23:56
• Updated: 02/Oct/19 17:23
• Resolved: 10/Jun/14 12:40

Description

Due to a misconfiguration in one of our QA clusters, we uncovered a leak in CloudSolrServer. If this line throws:

https://github.com/apache/lucene-solr/blob/branch_4x/solr/solrj/src/java/org/apache/solr/client/solrj/impl/CloudSolrServer.java#L242

then the instantiated ZkStateReader is leaked.

Here's the stacktrace of the Exception (we're using a custom build so the line numbers won't quite match up, but it gives the idea):
at org.apache.solr.client.solrj.impl.CloudSolrServer.connect(CloudSolrServer.java:304) at org.apache.solr.client.solrj.impl.CloudSolrServer.requestWithRetryOnStaleState(CloudSolrServer.java:568) at org.apache.solr.client.solrj.impl.CloudSolrServer.request(CloudSolrServer.java:557) at org.apache.solr.client.solrj.request.AbstractUpdateRequest.process(AbstractUpdateRequest.java:117) at org.apache.solr.client.solrj.request.AbstractUpdateRequest.process(AbstractUpdateRequest.java:33) at com.apple.cie.search.client.crossdc.MirroredSolrRequestHandler.handleItem(MirroredSolrRequestHandler.java:100) at com.apple.cie.search.client.crossdc.MirroredSolrRequestHandler.handleItem(MirroredSolrRequestHandler.java:33) at com.apple.coda.queueing.CodaQueueConsumer$StreamProcessor.run(CodaQueueConsumer.java:147) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603) at java.lang.Thread.run(Thread.java:722) Caused by: org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for /live_nodes at org.apache.zookeeper.KeeperException.create(KeeperException.java:111) at org.apache.zookeeper.KeeperException.create(KeeperException.java:51) at org.apache.zookeeper.ZooKeeper.getChildren(ZooKeeper.java:1468) at org.apache.solr.common.cloud.SolrZkClient$6.execute(SolrZkClient.java:256) at org.apache.solr.common.cloud.SolrZkClient$6.execute(SolrZkClient.java:253) at org.apache.solr.common.cloud.ZkCmdExecutor.retryOperation(ZkCmdExecutor.java:73) at org.apache.solr.common.cloud.SolrZkClient.getChildren(SolrZkClient.java:253) at org.apache.solr.common.cloud.ZkStateReader.createClusterStateWatchersAndUpdate(ZkStateReader.java:305) at org.apache.solr.client.solrj.impl.CloudSolrServer.createZkStateReader(CloudSolrServer.java:935) at org.apache.solr.client.solrj.impl.CloudSolrServer.connect(CloudSolrServer.java:298) ... 10 more