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Edward Ribeiro edited comment on ZOOKEEPER-2572 at 9/13/16 10:11 PM: --------------------------------------------------------------------- Hey [~hanm], really good catch! :D /cc [~fpj], [~breed], [~rakesh_r] While studying this piece of code, I have seen a curious fact: *{{FileTxnLog.truncate}} never returns false*. It's either throws IOException or returns {{true}}. But then it's call hierarchy eventually calls {{ZkDatabase.truncateLog}} as below (my comments are in upper case below): {code} public boolean truncateLog(long zxid) throws IOException { clear(); // truncate the log boolean truncated = snapLog.truncateLog(zxid); // IT WILL NEVER ENTER IN THIS IF if (!truncated) { return false; } loadDataBase(); return true; } {code} And the method above is called by {{Learner.syncWithLeader}}, again with a snippet below that will never be called, plus getting out of the {{syncWithLeader}} middway. {code} boolean truncated=zk.getZKDatabase().truncateLog(qp.getZxid()); // AGAIN, NEVER CAN WILL BE TRUE if (!truncated) { // not able to truncate the log LOG.error("Not able to truncate the log " + Long.toHexString(qp.getZxid())); System.exit(13); } {code} Does it make sense what I am saying? was (Author: eribeiro): Hey [~hanm], really good catch! :D /cc [~fpj], [~breed], [~rakesh_r] While studying this piece of code, I have seen a curious fact: *{{FileTxnLog.truncate}} never returns false*. It's either throws IOException or returns {{true}}. But then it's call hierarchy eventually calls {{ZkDatabase.truncateLog}} as below (my comments are in upper case below): {code} public boolean truncateLog(long zxid) throws IOException { clear(); // truncate the log boolean truncated = snapLog.truncateLog(zxid); // IT WILL NEVER ENTER IN THIS IF if (!truncated) { return false; } loadDataBase(); return true; } {code} And the method above is called by {{Learner.syncWithLeader}}, again with a snippet below that will never be called, plus getting out of the {{syncWithLeader}} middway. {quote} boolean truncated=zk.getZKDatabase().truncateLog(qp.getZxid()); // AGAIN, NEVER CAN WILL BE TRUE if (!truncated) { // not able to truncate the log LOG.error("Not able to truncate the log " + Long.toHexString(qp.getZxid())); System.exit(13); } {quote} Does it make sense what I am saying? > Potential resource leak in FileTxnLog.truncate > ---------------------------------------------- > > Key: ZOOKEEPER-2572 > URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2572 > Project: ZooKeeper > Issue Type: Bug > Components: server > Affects Versions: 3.4.9, 3.5.2 > Reporter: Michael Han > Fix For: 3.4.10, 3.5.3 > > > In FileTxnLog.truncate, we have: > {code} > public boolean truncate(long zxid) throws IOException { > FileTxnIterator itr = null; > try { > itr = new FileTxnIterator(this.logDir, zxid); > PositionInputStream input = itr.inputStream; > if(input == null) { > throw new IOException("No log files found to truncate! This > could " + > "happen if you still have snapshots from an old setup > or " + > "log files were deleted accidentally or dataLogDir > was changed in zoo.cfg."); > } > long pos = input.getPosition(); > // now, truncate at the current position > RandomAccessFile raf=new RandomAccessFile(itr.logFile,"rw"); > raf.setLength(pos); > raf.close(); > while(itr.goToNextLog()) { > if (!itr.logFile.delete()) { > LOG.warn("Unable to truncate {}", itr.logFile); > } > } > } finally { > close(itr); > } > return true; > } > {code} > {{raf}} here can be potentially in a state of not closed after leaving the > method, if there is an (IO) exception thrown from setLength. -- This message was sent by Atlassian JIRA (v6.3.4#6332)