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Andrew Purtell commented on HBASE-11813: ---------------------------------------- Not that a scanner that never returns is better but can we do this without recursion? > CellScanner#advance may infinitely recurse > ------------------------------------------ > > Key: HBASE-11813 > URL: https://issues.apache.org/jira/browse/HBASE-11813 > Project: HBase > Issue Type: Bug > Reporter: Andrew Purtell > Priority: Blocker > Fix For: 0.99.0, 2.0.0, 0.98.6 > > > On user@hbase, johannes.schab...@visual-meta.com reported: > {quote} > we face a serious issue with our HBase production cluster for two days now. > Every couple minutes, a random RegionServer gets stuck and does not process > any requests. In addition this causes the other RegionServers to freeze > within a minute which brings down the entire cluster. Stopping the affected > RegionServer unblocks the cluster and everything comes back to normal. > {quote} > Subsequent troubleshooting reveals that RPC is getting stuck because we are > losing RPC handlers. In the .out files we have this: > {noformat} > Exception in thread "defaultRpcServer.handler=5,queue=2,port=60020" > java.lang.StackOverflowError > at org.apache.hadoop.hbase.CellUtil$1.advance(CellUtil.java:210) > at org.apache.hadoop.hbase.CellUtil$1.advance(CellUtil.java:210) > at org.apache.hadoop.hbase.CellUtil$1.advance(CellUtil.java:210) > at org.apache.hadoop.hbase.CellUtil$1.advance(CellUtil.java:210) > [...] > Exception in thread "defaultRpcServer.handler=5,queue=2,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=18,queue=0,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=23,queue=2,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=24,queue=0,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=2,queue=2,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=11,queue=2,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=25,queue=1,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=20,queue=2,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=19,queue=1,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=15,queue=0,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=1,queue=1,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=7,queue=1,port=60020" > java.lang.StackOverflowError > Exception in thread "defaultRpcServer.handler=4,queue=1,port=60020" > java.lang.StackOverflowError​ > {noformat} > That is the anonymous CellScanner instance we create from > CellUtil#createCellScanner: > {code} > ​ return new CellScanner() { > private final Iterator<? extends CellScannable> iterator = > cellScannerables.iterator(); > private CellScanner cellScanner = null; > @Override > public Cell current() { > return this.cellScanner != null? this.cellScanner.current(): null; > } > @Override > public boolean advance() throws IOException { > if (this.cellScanner == null) { > if (!this.iterator.hasNext()) return false; > this.cellScanner = this.iterator.next().cellScanner(); > } > if (this.cellScanner.advance()) return true; > this.cellScanner = null; > ---> return advance(); > } > }; > {code} > That final return statement is the immediate problem. > We should also fix this so the RegionServer aborts if it loses a handler to > an Error. -- This message was sent by Atlassian JIRA (v6.2#6252)