Examples with Key org.apache.hadoop.util.bloom.Key used on opensource projects

Example 1 with Key

use of org.apache.hadoop.util.bloom.Key in project compiler by boalang.

the class DistinctAggregator method aggregate.

/** {@inheritDoc} */
@Override
public void aggregate(final String data, final String metadata) throws IOException, InterruptedException {
    // instantiate a bloom filter input key initialized by the data
    Key key = new Key(data.getBytes());
    // if the key is already in the filter, forget it
    if (this.filter.membershipTest(key))
        return;
    // add the key to the bloom filter
    this.filter.add(key);
    // and collect it
    this.collect(data);
}

Example 2 with Key

use of org.apache.hadoop.util.bloom.Key in project compiler by boalang.

the class UniqueAggregator method aggregate.

/** {@inheritDoc} */
@Override
public void aggregate(final String data, final String metadata) throws IOException, InterruptedException {
    // instantiate a bloom filter input key initialized by the data
    final Key key = new Key(data.getBytes());
    // if the key is already in the filter, forget about it
    if (this.filter.membershipTest(key))
        return;
    // add the key to the bloom filter
    this.filter.add(key);
    if (this.isCombining())
        this.collect(data);
    else
        this.total++;
}

Example 3 with Key

use of org.apache.hadoop.util.bloom.Key in project accumulo by apache.

the class RowFunctor method transform.

@Override
public Key transform(org.apache.accumulo.core.data.Key acuKey) {
    byte[] keyData;
    ByteSequence row = acuKey.getRowData();
    keyData = new byte[row.length()];
    System.arraycopy(row.getBackingArray(), 0, keyData, 0, row.length());
    return new Key(keyData, 1.0);
}

Example 4 with Key

use of org.apache.hadoop.util.bloom.Key in project Gaffer by gchq.

the class AccumuloIDBetweenSetsRetrieverTest method shouldDealWithFalsePositives.

private void shouldDealWithFalsePositives(final boolean loadIntoMemory, final AccumuloStore store) throws StoreException {
    final Set<EntityId> seeds = new HashSet<>();
    seeds.add(AccumuloTestData.SEED_A0);
    seeds.add(AccumuloTestData.SEED_A23);
    // positive sensible.
    for (int i = 0; i < 10; i++) {
        seeds.add(new EntitySeed("abc" + i));
    }
    // Need to make sure that the Bloom filter we create has the same size and the same number of hashes as the
    // one that GraphElementsWithStatisticsWithinSetRetriever creates.
    final int numItemsToBeAdded = loadIntoMemory ? seeds.size() : 20;
    if (!loadIntoMemory) {
        store.getProperties().setMaxEntriesForBatchScanner("20");
    }
    // Find something that will give a false positive
    // Need to repeat the logic used in the getGraphElementsWithStatisticsWithinSet() method.
    // Calculate sensible size of filter, aiming for false positive rate of 1 in 10000, with a maximum size of
    // maxBloomFilterToPassToAnIterator bytes.
    int size = (int) (-numItemsToBeAdded * Math.log(0.0001) / Math.pow(Math.log(2.0), 2.0));
    size = Math.min(size, store.getProperties().getMaxBloomFilterToPassToAnIterator());
    // Work out optimal number of hashes to use in Bloom filter based on size of set - optimal number of hashes is
    // (m/n)ln 2 where m is the size of the filter in bits and n is the number of items that will be added to the set.
    final int numHashes = Math.max(1, (int) ((size / numItemsToBeAdded) * Math.log(2)));
    // Create Bloom filter and add seeds to it
    final BloomFilter filter = new BloomFilter(size, numHashes, Hash.MURMUR_HASH);
    for (final EntityId seed : seeds) {
        filter.add(new Key(store.getKeyPackage().getKeyConverter().serialiseVertex(seed.getVertex())));
    }
    // Test random items against it - should only have to shouldRetrieveElementsInRangeBetweenSeeds MAX_SIZE_BLOOM_FILTER / 2 on average before find a
    // false positive (but impose an arbitrary limit to avoid an infinite loop if there's a problem).
    int count = 0;
    int maxNumberOfTries = 50 * store.getProperties().getMaxBloomFilterToPassToAnIterator();
    while (count < maxNumberOfTries) {
        count++;
        if (filter.membershipTest(new Key(("" + count).getBytes()))) {
            break;
        }
    }
    if (count == maxNumberOfTries) {
        fail("Didn't find a false positive");
    }
    // False positive is "" + count so create an edge from seeds to that
    final Edge edge = new Edge.Builder().group(TestGroups.EDGE).source("A0").dest("" + count).directed(true).build();
    edge.putProperty(AccumuloPropertyNames.COUNT, 1000000);
    Set<Element> data = new HashSet<>();
    data.add(edge);
    final User user = new User();
    addElements(data, store, user);
    // Now query for all edges in set - shouldn't get the false positive
    GetElementsBetweenSets op = new GetElementsBetweenSets.Builder().input(AccumuloTestData.SEED_A0_SET).inputB(seeds).view(defaultView).build();
    final Set<Element> results = returnElementsFromOperation(store, op, new User(), loadIntoMemory);
    // Check results are as expected
    assertThat(results).hasSize(2).contains(AccumuloTestData.EDGE_A0_A23, AccumuloTestData.A0_ENTITY);
}

Example 5 with Key

use of org.apache.hadoop.util.bloom.Key in project Gaffer by gchq.

the class FilterWritabilityTest method shouldAcceptValidFilter.

@Test
public void shouldAcceptValidFilter() {
    // Given
    final BloomFilter filter = new BloomFilter(100, 5, Hash.MURMUR_HASH);
    filter.add(new Key("ABC".getBytes()));
    filter.add(new Key("DEF".getBytes()));
    // Then
    assertTrue(filter.membershipTest(new Key("ABC".getBytes())));
    assertTrue(filter.membershipTest(new Key("DEF".getBytes())));
    assertFalse(filter.membershipTest(new Key("lkjhgfdsa".getBytes())));
}