Github user kameshb commented on a diff in the pull request: https://github.com/apache/drill/pull/1027#discussion_r152285907 --- Diff: contrib/storage-kafka/src/main/java/org/apache/drill/exec/store/kafka/KafkaRecordReader.java --- @@ -0,0 +1,145 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ +package org.apache.drill.exec.store.kafka; + +import java.util.Collection; +import java.util.List; +import java.util.Set; +import java.util.concurrent.TimeUnit; + +import org.apache.drill.common.exceptions.ExecutionSetupException; +import org.apache.drill.common.exceptions.UserException; +import org.apache.drill.common.expression.SchemaPath; +import org.apache.drill.exec.ExecConstants; +import org.apache.drill.exec.ops.FragmentContext; +import org.apache.drill.exec.ops.OperatorContext; +import org.apache.drill.exec.physical.impl.OutputMutator; +import org.apache.drill.exec.server.options.OptionManager; +import org.apache.drill.exec.store.AbstractRecordReader; +import org.apache.drill.exec.store.kafka.KafkaSubScan.KafkaSubScanSpec; +import org.apache.drill.exec.store.kafka.decoders.MessageReader; +import org.apache.drill.exec.store.kafka.decoders.MessageReaderFactory; +import org.apache.drill.exec.util.Utilities; +import org.apache.drill.exec.vector.complex.impl.VectorContainerWriter; +import org.apache.kafka.clients.consumer.ConsumerRecord; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import com.google.common.base.Stopwatch; +import com.google.common.collect.Lists; +import com.google.common.collect.Sets; + +public class KafkaRecordReader extends AbstractRecordReader { + private static final Logger logger = LoggerFactory.getLogger(KafkaRecordReader.class); + public static final long DEFAULT_MESSAGES_PER_BATCH = 4000; + + private VectorContainerWriter writer; + private MessageReader messageReader; + + private final boolean unionEnabled; + private final KafkaStoragePlugin plugin; + private final KafkaSubScanSpec subScanSpec; + private final long kafkaPollTimeOut; + + private long currentOffset; + private MessageIterator msgItr; + + private final boolean enableAllTextMode; + private final boolean readNumbersAsDouble; + private final String kafkaMsgReader; + + public KafkaRecordReader(KafkaSubScan.KafkaSubScanSpec subScanSpec, List<SchemaPath> projectedColumns, + FragmentContext context, KafkaStoragePlugin plugin) { + setColumns(projectedColumns); + this.enableAllTextMode = context.getOptions().getOption(ExecConstants.KAFKA_ALL_TEXT_MODE).bool_val; + this.readNumbersAsDouble = context.getOptions() + .getOption(ExecConstants.KAFKA_READER_READ_NUMBERS_AS_DOUBLE).bool_val; + OptionManager options = context.getOptions(); + this.unionEnabled = options.getOption(ExecConstants.ENABLE_UNION_TYPE); + this.kafkaMsgReader = options.getOption(ExecConstants.KAFKA_RECORD_READER).string_val; + this.kafkaPollTimeOut = options.getOption(ExecConstants.KAFKA_POLL_TIMEOUT).num_val; + this.plugin = plugin; + this.subScanSpec = subScanSpec; + } + + @Override + protected Collection<SchemaPath> transformColumns(Collection<SchemaPath> projectedColumns) { + Set<SchemaPath> transformed = Sets.newLinkedHashSet(); + if (!isStarQuery()) { + for (SchemaPath column : projectedColumns) { + transformed.add(column); + } + } else { + transformed.add(Utilities.STAR_COLUMN); + } + return transformed; + } + + @Override + public void setup(OperatorContext context, OutputMutator output) throws ExecutionSetupException { + this.writer = new VectorContainerWriter(output, unionEnabled); + messageReader = MessageReaderFactory.getMessageReader(kafkaMsgReader); + messageReader.init(context.getManagedBuffer(), Lists.newArrayList(getColumns()), this.writer, + this.enableAllTextMode, this.readNumbersAsDouble); + msgItr = new MessageIterator(messageReader.getConsumer(plugin), subScanSpec, kafkaPollTimeOut); + } + + /** + * KafkaConsumer.poll will fetch 500 messages per poll call. So hasNext will + * take care of polling multiple times for this given batch next invocation + */ + @Override + public int next() { + writer.allocate(); + writer.reset(); + Stopwatch watch = Stopwatch.createStarted(); + int messageCount = 0; + + try { + while (currentOffset < subScanSpec.getEndOffset() - 1 && msgItr.hasNext()) { + ConsumerRecord<byte[], byte[]> consumerRecord = msgItr.next(); + currentOffset = consumerRecord.offset(); + writer.setPosition(messageCount); + messageReader.readMessage(consumerRecord); + if (++messageCount >= DEFAULT_MESSAGES_PER_BATCH) { + break; + } + } + + messageReader.ensureAtLeastOneField(); + writer.setValueCount(messageCount); + logger.debug("Took {} ms to process {} records.", watch.elapsed(TimeUnit.MILLISECONDS), messageCount); + logger.debug("Last offset consumed for {}:{} is {}", subScanSpec.getTopicName(), subScanSpec.getPartitionId(), + currentOffset); + return messageCount; + } catch (Exception e) { + String msg = "Failure while reading messages from kafka. Recordreader was at record: " + (messageCount + 1); + throw UserException.dataReadError(e).message(msg).addContext(e.getMessage()).build(logger); + } + } + + @Override + public void close() throws Exception { + logger.info("Last offset processed for {}:{} is - {}", subScanSpec.getTopicName(), subScanSpec.getPartitionId(), --- End diff -- This would help while debugging if there any issues. That is the reason why made it info and most of other are logged as debug.
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