Examples with PaxosValue com.palantir.paxos.PaxosValue used on opensource projects

Example 1 with PaxosValue

use of com.palantir.paxos.PaxosValue in project atlasdb by palantir.

the class PaxosLeaderElectionService method updateLearnedStateFromPeers.

/**
 * Queries all other learners for unknown learned values
 *
 * @returns true if new state was learned, otherwise false
 */
public boolean updateLearnedStateFromPeers(Optional<PaxosValue> greatestLearned) {
    final long nextToLearnSeq = greatestLearned.map(value -> value.getRound()).orElse(PaxosAcceptor.NO_LOG_ENTRY) + 1;
    List<PaxosUpdate> updates = PaxosQuorumChecker.<PaxosLearner, PaxosUpdate>collectQuorumResponses(learners, new Function<PaxosLearner, PaxosUpdate>() {

        @Override
        @Nullable
        public PaxosUpdate apply(@Nullable PaxosLearner learner) {
            return new PaxosUpdate(copyOf(learner.getLearnedValuesSince(nextToLearnSeq)));
        }
    }, proposer.getQuorumSize(), executor, PaxosQuorumChecker.DEFAULT_REMOTE_REQUESTS_TIMEOUT_IN_SECONDS);
    // learn the state accumulated from peers
    boolean learned = false;
    for (PaxosUpdate update : updates) {
        ImmutableCollection<PaxosValue> values = update.getValues();
        for (PaxosValue value : values) {
            PaxosValue currentLearnedValue = knowledge.getLearnedValue(value.getRound());
            if (currentLearnedValue == null) {
                knowledge.learn(value.getRound(), value);
                learned = true;
            }
        }
    }
    return learned;
}

Example 2 with PaxosValue

use of com.palantir.paxos.PaxosValue in project atlasdb by palantir.

the class LeaderRemotingTest method testAccept.

@Test
public void testAccept() throws IOException {
    PaxosProposalId id = new PaxosProposalId(123123, UUID.randomUUID().toString());
    PaxosProposal paxosProposal = new PaxosProposal(id, new PaxosValue(id.getProposerUUID(), 0, new byte[] { 0, 1, 2, 4, 1 }));
    PaxosAcceptor accept = AtlasDbFeignTargetFactory.createProxy(Optional.empty(), acceptor.baseUri().toString(), PaxosAcceptor.class, UserAgents.DEFAULT_USER_AGENT);
    accept.accept(0, paxosProposal);
    accept.getLatestSequencePreparedOrAccepted();
    accept.prepare(0, id);
    accept.prepare(1, id);
}

Example 3 with PaxosValue

use of com.palantir.paxos.PaxosValue in project atlasdb by palantir.

the class PaxosTimestampBoundStore method storeUpperLimit.

/**
 * Proposes a new timestamp limit, with sequence number 1 greater than the current agreed bound, or
 * PaxosAcceptor.NO_LOG_ENTRY + 1 if nothing has been proposed or accepted yet.
 *
 * @param limit the new upper limit to be stored
 * @throws IllegalArgumentException if trying to persist a limit smaller than the agreed limit
 * @throws NotCurrentLeaderException if the timestamp limit has changed out from under us
 */
@Override
public synchronized void storeUpperLimit(long limit) throws MultipleRunningTimestampServiceError {
    long newSeq = PaxosAcceptor.NO_LOG_ENTRY + 1;
    if (agreedState != null) {
        Preconditions.checkArgument(limit >= agreedState.getBound(), "Tried to store an upper limit %s less than the current limit %s", limit, agreedState.getBound());
        newSeq = agreedState.getSeqId() + 1;
    }
    while (true) {
        try {
            proposer.propose(newSeq, PtBytes.toBytes(limit));
            PaxosValue value = knowledge.getLearnedValue(newSeq);
            checkAgreedBoundIsOurs(limit, newSeq, value);
            long newLimit = PtBytes.toLong(value.getData());
            agreedState = ImmutableSequenceAndBound.of(newSeq, newLimit);
            if (newLimit < limit) {
                // The bound is ours, but is not high enough.
                // This is dangerous; proposing at the next sequence number is unsafe, as timestamp services
                // generally assume they have the ALLOCATION_BUFFER_SIZE timestamps up to this.
                // TODO (jkong): Devise a method that better preserves availability of the cluster.
                log.warn("It appears we updated the timestamp limit to {}, which was less than our target {}." + " This suggests we have another timestamp service running; possibly because we" + " lost and regained leadership. For safety, we are now stopping this service.", SafeArg.of("newLimit", newLimit), SafeArg.of("target", limit));
                throw new NotCurrentLeaderException(String.format("We updated the timestamp limit to %s, which was less than our target %s.", newLimit, limit));
            }
            return;
        } catch (PaxosRoundFailureException e) {
            waitForRandomBackoff(e, this::wait);
        }
    }
}

Example 4 with PaxosValue

use of com.palantir.paxos.PaxosValue in project atlasdb by palantir.

the class LeadersTest method canCreateProxyAndLocalListOfPaxosLearners.

@Test
public void canCreateProxyAndLocalListOfPaxosLearners() {
    PaxosLearner localLearner = mock(PaxosLearner.class);
    PaxosValue value = mock(PaxosValue.class);
    when(localLearner.getGreatestLearnedValue()).thenReturn(value);
    List<PaxosLearner> paxosLearners = Leaders.createProxyAndLocalList(localLearner, REMOTE_SERVICE_ADDRESSES, Optional.empty(), PaxosLearner.class);
    MatcherAssert.assertThat(paxosLearners.size(), is(REMOTE_SERVICE_ADDRESSES.size() + 1));
    paxosLearners.forEach(object -> MatcherAssert.assertThat(object, not(nullValue())));
    MatcherAssert.assertThat(Iterables.getLast(paxosLearners).getGreatestLearnedValue(), is(value));
    verify(localLearner).getGreatestLearnedValue();
    verifyNoMoreInteractions(localLearner);
}

Example 5 with PaxosValue

use of com.palantir.paxos.PaxosValue in project atlasdb by palantir.

the class LeaderRemotingTest method testLearn.

@Test
public void testLearn() throws IOException {
    PaxosValue value = new PaxosValue("asdfasdfsa", 0, new byte[] { 0, 1, 2 });
    PaxosLearner learn = AtlasDbFeignTargetFactory.createProxy(Optional.empty(), learner.baseUri().toString(), PaxosLearner.class, UserAgents.DEFAULT_USER_AGENT);
    learn.getGreatestLearnedValue();
    learn.getLearnedValuesSince(0);
    learn.learn(0, value);
    PaxosValue val = learn.getGreatestLearnedValue();
    learn.getLearnedValuesSince(0);
    learn.getLearnedValue(0);
}