Package org.exist.storage.journal

Examples of org.exist.storage.journal.JournalReader


    final int lastNum = Journal.findLastFile(files);
    if (-1 < lastNum) {
            // load the last log file
      final File last = logManager.getFile(lastNum);
      // scan the last log file and record the last checkpoint found
      final JournalReader reader = new JournalReader(broker, last, lastNum);
            try {
              // try to read the last log record to see if it is a checkpoint
              boolean checkpointFound = false;
          try {
                    final Loggable lastLog = reader.lastEntry();
                    if (lastLog != null && lastLog.getLogType() == LogEntryTypes.CHECKPOINT) {
                      final Checkpoint checkpoint = (Checkpoint) lastLog;
                      // Found a checkpoint. To be sure it is indeed a valid checkpoint
                      // record, we compare the LSN stored in it with the current LSN.
                      if (checkpoint.getStoredLsn() == checkpoint.getLsn()) {
                        checkpointFound = true;
                        LOG.debug("Database is in clean state. Last checkpoint: " +
                            checkpoint.getDateString());
                      }
                    }
                } catch (final LogException e) {
                    LOG.info("Reading last journal log entry failed: " + e.getMessage() + ". Will scan the log...");
                    // if an exception occurs at this point, the journal file is probably incomplete,
                    // which indicates a db crash
                    checkpointFound = false;
                }
          if (!checkpointFound) {
                    LOG.info("Unclean shutdown detected. Scanning journal...");
                    broker.getBrokerPool().reportStatus("Unclean shutdown detected. Scanning log...");
            reader.position(1);
            final Long2ObjectHashMap<Loggable> txnsStarted = new Long2ObjectHashMap<Loggable>();
            Checkpoint lastCheckpoint = null;
            long lastLsn = Lsn.LSN_INVALID;
                  Loggable next;
                  try {
            final ProgressBar progress = new ProgressBar("Scanning journal ", last.length());
                while ((next = reader.nextEntry()) != null) {
//                          LOG.debug(next.dump());
              progress.set(Lsn.getOffset(next.getLsn()));
              if (next.getLogType() == LogEntryTypes.TXN_START) {
                        // new transaction starts: add it to the transactions table
                        txnsStarted.put(next.getTransactionId(), next);
                    } else if (next.getLogType() == LogEntryTypes.TXN_ABORT) {
                      // transaction aborted: remove it from the transactions table
                      txnsStarted.remove(next.getTransactionId());
                    } else if (next.getLogType() == LogEntryTypes.CHECKPOINT) {
                      txnsStarted.clear();
                    lastCheckpoint = (Checkpoint) next;
                    }
                  lastLsn = next.getLsn();
                }
                  } catch (final LogException e) {
                      if (LOG.isDebugEnabled()) {
                            LOG.debug("Caught exception while reading log", e);
                        }
                        LOG.info("Last readable journal log entry lsn: " + Lsn.dump(lastLsn));
                    }

            // if the last checkpoint record is not the last record in the file
            // we need a recovery.
            if ((lastCheckpoint == null || lastCheckpoint.getLsn() != lastLsn) &&
                txnsStarted.size() > 0) {
              LOG.info("Dirty transactions: " + txnsStarted.size());
              // starting recovery: reposition the log reader to the last checkpoint
            if (lastCheckpoint == null)
                {reader.position(1);}
            else {
                reader.position(lastCheckpoint.getLsn());
                next = reader.nextEntry();
            }
                      recoveryRun = true;
                        try {
                            LOG.info("Running recovery...");
                            broker.getBrokerPool().reportStatus("Running recovery...");
                            doRecovery(txnsStarted.size(), last, reader, lastLsn);
                        } catch (final LogException e) {
                            // if restartOnError == true, we try to bring up the database even if there
                            // are errors. Otherwise, an exception is thrown, which will stop the db initialization
                            broker.getBrokerPool().reportStatus(BrokerPool.SIGNAL_ABORTED);
                            if (restartOnError) {
                                LOG.error("Aborting recovery. eXist-db detected an error during recovery. This may not be fatal. Database will start up, but corruptions are likely.");
                            } else {
                                LOG.error("Aborting recovery. eXist-db detected an error during recovery. This may not be fatal. Please consider running a consistency check via the export tool and create a backup if problems are reported. The db should come up again if you restart it.");
                                throw e;
                            }
                        }
                    } else
              {LOG.info("Database is in clean state. Nothing to recover from the journal.");}
          }
            } finally {
                reader.close();
                // remove .log files from directory even if recovery failed.
                // Re-applying them on a second start up attempt would definitely damage the db, so we better
                // delete them before user tries to launch again.
                cleanDirectory(files);
                if (recoveryRun) {
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