Examples with TransactionLogEntryCursor org.neo4j.kernel.impl.transaction.log.TransactionLogEntryCursor used on opensource projects

Example 1 with TransactionLogEntryCursor

use of org.neo4j.kernel.impl.transaction.log.TransactionLogEntryCursor in project neo4j by neo4j.

the class DumpLogicalLog method dump.

public void dump(String filenameOrDirectory, PrintStream out, Predicate<LogEntry[]> filter, Function<LogEntry, String> serializer) throws IOException {
    File file = new File(filenameOrDirectory);
    printFile(file, out);
    File firstFile;
    LogVersionBridge bridge;
    if (file.isDirectory()) {
        // Use natural log version bridging if a directory is supplied
        final PhysicalLogFiles logFiles = new PhysicalLogFiles(file, fileSystem);
        bridge = new ReaderLogVersionBridge(fileSystem, logFiles) {

            @Override
            public LogVersionedStoreChannel next(LogVersionedStoreChannel channel) throws IOException {
                LogVersionedStoreChannel next = super.next(channel);
                if (next != channel) {
                    printFile(logFiles.getLogFileForVersion(next.getVersion()), out);
                }
                return next;
            }
        };
        firstFile = logFiles.getLogFileForVersion(logFiles.getLowestLogVersion());
    } else {
        // Use no bridging, simple reading this single log file if a file is supplied
        firstFile = file;
        bridge = NO_MORE_CHANNELS;
    }
    StoreChannel fileChannel = fileSystem.open(firstFile, "r");
    ByteBuffer buffer = ByteBuffer.allocateDirect(LOG_HEADER_SIZE);
    LogHeader logHeader;
    try {
        logHeader = readLogHeader(buffer, fileChannel, false, firstFile);
    } catch (IOException ex) {
        out.println("Unable to read timestamp information, no records in logical log.");
        out.println(ex.getMessage());
        fileChannel.close();
        throw ex;
    }
    out.println("Logical log format: " + logHeader.logFormatVersion + " version: " + logHeader.logVersion + " with prev committed tx[" + logHeader.lastCommittedTxId + "]");
    PhysicalLogVersionedStoreChannel channel = new PhysicalLogVersionedStoreChannel(fileChannel, logHeader.logVersion, logHeader.logFormatVersion);
    ReadableClosablePositionAwareChannel logChannel = new ReadAheadLogChannel(channel, bridge, DEFAULT_READ_AHEAD_SIZE);
    LogEntryReader<ReadableClosablePositionAwareChannel> entryReader = new VersionAwareLogEntryReader<>();
    IOCursor<LogEntry> entryCursor = new LogEntryCursor(entryReader, logChannel);
    TransactionLogEntryCursor transactionCursor = new TransactionLogEntryCursor(entryCursor);
    try (IOCursor<LogEntry[]> cursor = filter == null ? transactionCursor : new FilteringIOCursor<>(transactionCursor, filter)) {
        while (cursor.next()) {
            for (LogEntry entry : cursor.get()) {
                out.println(serializer.apply(entry));
            }
        }
    }
}