Examples with UpdateType org.wali.UpdateType used on opensource projects

Example 6 with UpdateType

use of org.wali.UpdateType in project nifi by apache.

the class HashMapSnapshot method recover.

@Override
public SnapshotRecovery<T> recover() throws IOException {
    final File partialFile = getPartialFile();
    final File snapshotFile = getSnapshotFile();
    final boolean partialExists = partialFile.exists();
    final boolean snapshotExists = snapshotFile.exists();
    // return an empty recovery.
    if (!partialExists && !snapshotExists) {
        return SnapshotRecovery.emptyRecovery();
    }
    if (partialExists && snapshotExists) {
        // both files exist -- assume NiFi crashed/died while checkpointing. Delete the partial file.
        Files.delete(partialFile.toPath());
    } else if (partialExists) {
        // partial exists but snapshot does not -- we must have completed
        // creating the partial, deleted the snapshot
        // but crashed before renaming the partial to the snapshot. Just
        // rename partial to snapshot
        Files.move(partialFile.toPath(), snapshotFile.toPath());
    }
    if (snapshotFile.length() == 0) {
        logger.warn("{} Found 0-byte Snapshot file; skipping Snapshot file in recovery", this);
        return SnapshotRecovery.emptyRecovery();
    }
    // or we renamed partialPath to snapshotPath. So just Recover from snapshotPath.
    try (final DataInputStream dataIn = new DataInputStream(new BufferedInputStream(new FileInputStream(snapshotFile)))) {
        // Ensure that the header contains the information that we expect and retrieve the relevant information from the header.
        final SnapshotHeader header = validateHeader(dataIn);
        final SerDe<T> serde = header.getSerDe();
        final int serdeVersion = header.getSerDeVersion();
        final int numRecords = header.getNumRecords();
        final long maxTransactionId = header.getMaxTransactionId();
        // Read all of the records that we expect to receive.
        for (int i = 0; i < numRecords; i++) {
            final T record = serde.deserializeRecord(dataIn, serdeVersion);
            if (record == null) {
                throw new EOFException();
            }
            final UpdateType updateType = serde.getUpdateType(record);
            if (updateType == UpdateType.DELETE) {
                logger.warn("While recovering from snapshot, found record with type 'DELETE'; this record will not be restored");
                continue;
            }
            logger.trace("Recovered from snapshot: {}", record);
            recordMap.put(serde.getRecordIdentifier(record), record);
        }
        // Determine the location of any swap files.
        final int numSwapRecords = dataIn.readInt();
        final Set<String> swapLocations = new HashSet<>();
        for (int i = 0; i < numSwapRecords; i++) {
            swapLocations.add(dataIn.readUTF());
        }
        this.swapLocations.addAll(swapLocations);
        logger.info("{} restored {} Records and {} Swap Files from Snapshot, ending with Transaction ID {}", new Object[] { this, numRecords, swapLocations.size(), maxTransactionId });
        return new StandardSnapshotRecovery<>(recordMap, swapLocations, snapshotFile, maxTransactionId);
    }
}