Examples with DataResolver org.apache.cassandra.service.reads.DataResolver used on opensource projects

Example 1 with DataResolver

use of org.apache.cassandra.service.reads.DataResolver in project cassandra by apache.

the class AbstractReadRepair method startRepair.

// digestResolver isn't used here because we resend read requests to all participants
public void startRepair(DigestResolver<E, P> digestResolver, Consumer<PartitionIterator> resultConsumer) {
    getRepairMeter().mark();
    /*
         * When repaired data tracking is enabled, a digest will be created from data reads from repaired SSTables.
         * The digests from each replica can then be compared on the coordinator to detect any divergence in their
         * repaired datasets. In this context, an SSTable is considered repaired if it is marked repaired or has a 
         * pending repair session which has been committed. In addition to the digest, a set of ids for any pending but 
         * as yet uncommitted repair sessions is recorded and returned to the coordinator. This is to help reduce false 
         * positives caused by compaction lagging which can leave sstables from committed sessions in the pending state
         * for a time.
         */
    boolean trackRepairedStatus = DatabaseDescriptor.getRepairedDataTrackingForPartitionReadsEnabled();
    // Do a full data read to resolve the correct response (and repair node that need be)
    DataResolver<E, P> resolver = new DataResolver<>(command, replicaPlan, this, queryStartNanoTime, trackRepairedStatus);
    ReadCallback<E, P> readCallback = new ReadCallback<>(resolver, command, replicaPlan, queryStartNanoTime);
    digestRepair = new DigestRepair<>(resolver, readCallback, resultConsumer);
    // if enabled, request additional info about repaired data from any full replicas
    for (Replica replica : replicaPlan().contacts()) {
        sendReadCommand(replica, readCallback, false, trackRepairedStatus);
    }
    ReadRepairDiagnostics.startRepair(this, replicaPlan(), digestResolver);
}

Example 2 with DataResolver

use of org.apache.cassandra.service.reads.DataResolver in project cassandra by apache.

the class RangeCommandIterator method query.

/**
 * Queries the provided sub-range.
 *
 * @param replicaPlan the subRange to query.
 * @param isFirst in the case where multiple queries are sent in parallel, whether that's the first query on
 * that batch or not. The reason it matters is that whe paging queries, the command (more specifically the
 * {@code DataLimits}) may have "state" information and that state may only be valid for the first query (in
 * that it's the query that "continues" whatever we're previously queried).
 */
private SingleRangeResponse query(ReplicaPlan.ForRangeRead replicaPlan, boolean isFirst) {
    PartitionRangeReadCommand rangeCommand = command.forSubRange(replicaPlan.range(), isFirst);
    // If enabled, request repaired data tracking info from full replicas, but
    // only if there are multiple full replicas to compare results from.
    boolean trackRepairedStatus = DatabaseDescriptor.getRepairedDataTrackingForRangeReadsEnabled() && replicaPlan.contacts().filter(Replica::isFull).size() > 1;
    ReplicaPlan.SharedForRangeRead sharedReplicaPlan = ReplicaPlan.shared(replicaPlan);
    ReadRepair<EndpointsForRange, ReplicaPlan.ForRangeRead> readRepair = ReadRepair.create(command, sharedReplicaPlan, queryStartNanoTime);
    DataResolver<EndpointsForRange, ReplicaPlan.ForRangeRead> resolver = new DataResolver<>(rangeCommand, sharedReplicaPlan, readRepair, queryStartNanoTime, trackRepairedStatus);
    ReadCallback<EndpointsForRange, ReplicaPlan.ForRangeRead> handler = new ReadCallback<>(resolver, rangeCommand, sharedReplicaPlan, queryStartNanoTime);
    if (replicaPlan.contacts().size() == 1 && replicaPlan.contacts().get(0).isSelf()) {
        Stage.READ.execute(new StorageProxy.LocalReadRunnable(rangeCommand, handler, trackRepairedStatus));
    } else {
        for (Replica replica : replicaPlan.contacts()) {
            Tracing.trace("Enqueuing request to {}", replica);
            ReadCommand command = replica.isFull() ? rangeCommand : rangeCommand.copyAsTransientQuery(replica);
            Message<ReadCommand> message = command.createMessage(trackRepairedStatus && replica.isFull());
            MessagingService.instance().sendWithCallback(message, replica.endpoint(), handler);
        }
    }
    return new SingleRangeResponse(resolver, handler, readRepair);
}