KEYIN - the class of the input keysVALUEIN - the class of the input valuesKEYOUT - the class of the output keysVALUEOUT - the class of the output values@InterfaceAudience.Public @InterfaceStability.Evolving public interface ReduceContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT> extends TaskInputOutputContext<KEYIN,VALUEIN,KEYOUT,VALUEOUT>
Reducer.| Modifier and Type | Interface and Description |
|---|---|
static interface |
ReduceContext.ValueIterator<VALUEIN>
Iterator to iterate over values for a given group of records. |
APPLICATION_ATTEMPT_ID, APPLICATION_ATTEMPT_ID_ENV, APPLICATION_MASTER_CLASS, APPLICATION_TOKENS_FILE, CACHE_ARCHIVES, CACHE_ARCHIVES_SIZES, CACHE_ARCHIVES_TIMESTAMPS, CACHE_ARCHIVES_VISIBILITIES, CACHE_FILE_TIMESTAMPS, CACHE_FILE_VISIBILITIES, CACHE_FILES, CACHE_FILES_SIZES, CACHE_LOCALARCHIVES, CACHE_LOCALFILES, CACHE_SYMLINK, CLASSPATH_ARCHIVES, CLASSPATH_FILES, COMBINE_CLASS_ATTR, COMBINE_RECORDS_BEFORE_PROGRESS, COMPLETED_MAPS_FOR_REDUCE_SLOWSTART, COUNTER_GROUP_NAME_MAX_DEFAULT, COUNTER_GROUP_NAME_MAX_KEY, COUNTER_GROUPS_MAX_DEFAULT, COUNTER_GROUPS_MAX_KEY, COUNTER_NAME_MAX_DEFAULT, COUNTER_NAME_MAX_KEY, COUNTERS_MAX_DEFAULT, COUNTERS_MAX_KEY, DEFAULT_JOB_ACL_MODIFY_JOB, DEFAULT_JOB_ACL_VIEW_JOB, DEFAULT_JOB_AM_ACCESS_DISABLED, DEFAULT_LOG_LEVEL, DEFAULT_MAP_MEMORY_MB, DEFAULT_MAPRED_ADMIN_JAVA_OPTS, DEFAULT_MAPRED_ADMIN_USER_ENV, DEFAULT_MAX_SHUFFLE_FETCH_RETRY_DELAY, DEFAULT_MR_AM_ADMIN_COMMAND_OPTS, DEFAULT_MR_AM_COMMAND_OPTS, DEFAULT_MR_AM_COMMIT_WINDOW_MS, DEFAULT_MR_AM_COMMITTER_CANCEL_TIMEOUT_MS, DEFAULT_MR_AM_CONTAINERLAUNCHER_THREAD_COUNT_LIMIT, DEFAULT_MR_AM_HISTORY_COMPLETE_EVENT_FLUSH_TIMEOUT_MS, DEFAULT_MR_AM_HISTORY_JOB_COMPLETE_UNFLUSHED_MULTIPLIER, DEFAULT_MR_AM_HISTORY_MAX_UNFLUSHED_COMPLETE_EVENTS, DEFAULT_MR_AM_HISTORY_USE_BATCHED_FLUSH_QUEUE_SIZE_THRESHOLD, DEFAULT_MR_AM_IGNORE_BLACKLISTING_BLACKLISTED_NODE_PERCENT, DEFAULT_MR_AM_JOB_CLIENT_THREAD_COUNT, DEFAULT_MR_AM_JOB_REDUCE_PREEMPTION_LIMIT, DEFAULT_MR_AM_JOB_REDUCE_RAMP_UP_LIMIT, DEFAULT_MR_AM_LOG_LEVEL, DEFAULT_MR_AM_NUM_PROGRESS_SPLITS, DEFAULT_MR_AM_TASK_ESTIMATOR_SMOOTH_LAMBDA_MS, DEFAULT_MR_AM_TASK_LISTENER_THREAD_COUNT, DEFAULT_MR_AM_TO_RM_HEARTBEAT_INTERVAL_MS, DEFAULT_MR_AM_TO_RM_WAIT_INTERVAL_MS, DEFAULT_MR_AM_VMEM_MB, DEFAULT_MR_CLIENT_MAX_RETRIES, DEFAULT_MR_CLIENT_TO_AM_IPC_MAX_RETRIES, DEFAULT_REDUCE_MEMORY_MB, DEFAULT_SHELL, DEFAULT_SPLIT_METAINFO_MAXSIZE, GROUP_COMPARATOR_CLASS, HADOOP_WORK_DIR, ID, INDEX_CACHE_MEMORY_LIMIT, INPUT_FORMAT_CLASS_ATTR, IO_SORT_FACTOR, IO_SORT_MB, JAR, JAR_UNPACK_PATTERN, JOB_ACL_MODIFY_JOB, JOB_ACL_VIEW_JOB, JOB_AM_ACCESS_DISABLED, JOB_CANCEL_DELEGATION_TOKEN, JOB_CONF_FILE, JOB_JAR, JOB_JOBTRACKER_ID, JOB_LOCAL_DIR, JOB_NAME, JOB_NAMENODES, JOB_SPLIT, JOB_SPLIT_METAINFO, JOB_SUBMIT_DIR, JOB_SUBMITHOST, JOB_SUBMITHOSTADDR, JOB_UBERTASK_ENABLE, JOB_UBERTASK_MAXBYTES, JOB_UBERTASK_MAXMAPS, JOB_UBERTASK_MAXREDUCES, JVM_NUMTASKS_TORUN, KEY_COMPARATOR, MAP_CLASS_ATTR, MAP_COMBINE_MIN_SPILLS, MAP_DEBUG_SCRIPT, MAP_ENV, MAP_FAILURES_MAX_PERCENT, MAP_INPUT_FILE, MAP_INPUT_PATH, MAP_INPUT_START, MAP_JAVA_OPTS, MAP_LOG_LEVEL, MAP_MAX_ATTEMPTS, MAP_MEMORY_MB, MAP_MEMORY_PHYSICAL_MB, MAP_OUTPUT_COMPRESS, MAP_OUTPUT_COMPRESS_CODEC, MAP_OUTPUT_KEY_CLASS, MAP_OUTPUT_KEY_FIELD_SEPERATOR, MAP_OUTPUT_VALUE_CLASS, MAP_SKIP_INCR_PROC_COUNT, MAP_SKIP_MAX_RECORDS, MAP_SORT_SPILL_PERCENT, MAP_SPECULATIVE, MAPRED_ADMIN_USER_ENV, MAPRED_ADMIN_USER_SHELL, MAPRED_MAP_ADMIN_JAVA_OPTS, MAPRED_REDUCE_ADMIN_JAVA_OPTS, MAPREDUCE_JOB_CLASSLOADER, MAPREDUCE_JOB_CLASSLOADER_SYSTEM_CLASSES, MAPREDUCE_JOB_CREDENTIALS_BINARY, MAPREDUCE_JOB_DIR, MAPREDUCE_JOB_USER_CLASSPATH_FIRST, MAPREDUCE_V2_CHILD_CLASS, MAX_SHUFFLE_FETCH_RETRY_DELAY, MAX_TASK_FAILURES_PER_TRACKER, MR_AM_ADMIN_COMMAND_OPTS, MR_AM_ADMIN_USER_ENV, MR_AM_COMMAND_OPTS, MR_AM_COMMIT_WINDOW_MS, MR_AM_COMMITTER_CANCEL_TIMEOUT_MS, MR_AM_CONTAINERLAUNCHER_THREAD_COUNT_LIMIT, MR_AM_CREATE_JH_INTERMEDIATE_BASE_DIR, MR_AM_ENV, MR_AM_HISTORY_COMPLETE_EVENT_FLUSH_TIMEOUT_MS, MR_AM_HISTORY_JOB_COMPLETE_UNFLUSHED_MULTIPLIER, MR_AM_HISTORY_MAX_UNFLUSHED_COMPLETE_EVENTS, MR_AM_HISTORY_USE_BATCHED_FLUSH_QUEUE_SIZE_THRESHOLD, MR_AM_IGNORE_BLACKLISTING_BLACKLISTED_NODE_PERECENT, MR_AM_JOB_CLIENT_PORT_RANGE, MR_AM_JOB_CLIENT_THREAD_COUNT, MR_AM_JOB_NODE_BLACKLISTING_ENABLE, MR_AM_JOB_RECOVERY_ENABLE, MR_AM_JOB_RECOVERY_ENABLE_DEFAULT, MR_AM_JOB_REDUCE_PREEMPTION_LIMIT, MR_AM_JOB_REDUCE_RAMPUP_UP_LIMIT, MR_AM_JOB_SPECULATOR, MR_AM_LOG_LEVEL, MR_AM_NUM_PROGRESS_SPLITS, MR_AM_PREFIX, MR_AM_SECURITY_SERVICE_AUTHORIZATION_CLIENT, MR_AM_SECURITY_SERVICE_AUTHORIZATION_TASK_UMBILICAL, MR_AM_STAGING_DIR, MR_AM_TASK_ESTIMATOR, MR_AM_TASK_ESTIMATOR_EXPONENTIAL_RATE_ENABLE, MR_AM_TASK_ESTIMATOR_SMOOTH_LAMBDA_MS, MR_AM_TASK_LISTENER_THREAD_COUNT, MR_AM_TO_RM_HEARTBEAT_INTERVAL_MS, MR_AM_TO_RM_WAIT_INTERVAL_MS, MR_AM_VMEM_MB, MR_CLIENT_MAX_RETRIES, MR_CLIENT_TO_AM_IPC_MAX_RETRIES, MR_JOB_END_NOTIFICATION_MAX_ATTEMPTS, MR_JOB_END_NOTIFICATION_MAX_RETRY_INTERVAL, MR_JOB_END_NOTIFICATION_PROXY, MR_JOB_END_NOTIFICATION_URL, MR_JOB_END_RETRY_ATTEMPTS, MR_JOB_END_RETRY_INTERVAL, MR_PREFIX, NUM_MAP_PROFILES, NUM_MAPS, NUM_REDUCE_PROFILES, NUM_REDUCES, OUTPUT, OUTPUT_FORMAT_CLASS_ATTR, OUTPUT_KEY_CLASS, OUTPUT_VALUE_CLASS, PARTITIONER_CLASS_ATTR, PRESERVE_FAILED_TASK_FILES, PRESERVE_FILES_PATTERN, PRIORITY, QUEUE_NAME, RECORDS_BEFORE_PROGRESS, REDUCE_CLASS_ATTR, REDUCE_DEBUG_SCRIPT, REDUCE_ENV, REDUCE_FAILURES_MAXPERCENT, REDUCE_INPUT_BUFFER_PERCENT, REDUCE_JAVA_OPTS, REDUCE_LOG_LEVEL, REDUCE_MARKRESET_BUFFER_PERCENT, REDUCE_MARKRESET_BUFFER_SIZE, REDUCE_MAX_ATTEMPTS, REDUCE_MEMORY_MB, REDUCE_MEMORY_PHYSICAL_MB, REDUCE_MEMORY_TOTAL_BYTES, REDUCE_MEMTOMEM_ENABLED, REDUCE_MEMTOMEM_THRESHOLD, REDUCE_MERGE_INMEM_THRESHOLD, REDUCE_SKIP_INCR_PROC_COUNT, REDUCE_SKIP_MAXGROUPS, REDUCE_SPECULATIVE, SETUP_CLEANUP_NEEDED, SHUFFLE_CONNECT_TIMEOUT, SHUFFLE_FETCH_FAILURES, SHUFFLE_INPUT_BUFFER_PERCENT, SHUFFLE_MEMORY_LIMIT_PERCENT, SHUFFLE_MERGE_PERCENT, SHUFFLE_NOTIFY_READERROR, SHUFFLE_PARALLEL_COPIES, SHUFFLE_READ_TIMEOUT, SKIP_OUTDIR, SKIP_RECORDS, SKIP_START_ATTEMPTS, SPECULATIVE_SLOWNODE_THRESHOLD, SPECULATIVE_SLOWTASK_THRESHOLD, SPECULATIVECAP, SPLIT_FILE, SPLIT_METAINFO_MAXSIZE, STDERR_LOGFILE_ENV, STDOUT_LOGFILE_ENV, TASK_ATTEMPT_ID, TASK_CLEANUP_NEEDED, TASK_DEBUGOUT_LINES, TASK_ID, TASK_ISMAP, TASK_LOG_DIR, TASK_LOG_SIZE, TASK_MAP_PROFILE_PARAMS, TASK_OUTPUT_DIR, TASK_PARTITION, TASK_PROFILE, TASK_PROFILE_PARAMS, TASK_REDUCE_PROFILE_PARAMS, TASK_TEMP_DIR, TASK_TIMEOUT, TASK_TIMEOUT_CHECK_INTERVAL_MS, TASK_USERLOG_LIMIT, USER_LOG_RETAIN_HOURS, USER_NAME, WORKDIR, WORKING_DIR| Modifier and Type | Method and Description |
|---|---|
Iterable<VALUEIN> |
getValues()
Iterate through the values for the current key, reusing the same value
object, which is stored in the context.
|
boolean |
nextKey()
Start processing next unique key.
|
getCurrentKey, getCurrentValue, getOutputCommitter, nextKeyValue, writegetCounter, getCounter, getProgress, getStatus, getTaskAttemptID, setStatusgetArchiveClassPaths, getArchiveTimestamps, getCacheArchives, getCacheFiles, getCombinerClass, getConfiguration, getCredentials, getFileClassPaths, getFileTimestamps, getGroupingComparator, getInputFormatClass, getJar, getJobID, getJobName, getJobSetupCleanupNeeded, getLocalCacheArchives, getLocalCacheFiles, getMapOutputKeyClass, getMapOutputValueClass, getMapperClass, getMaxMapAttempts, getMaxReduceAttempts, getNumReduceTasks, getOutputFormatClass, getOutputKeyClass, getOutputValueClass, getPartitionerClass, getProfileEnabled, getProfileParams, getProfileTaskRange, getReducerClass, getSortComparator, getSymlink, getTaskCleanupNeeded, getUser, getWorkingDirectoryboolean nextKey()
throws IOException,
InterruptedException
IOExceptionInterruptedExceptionIterable<VALUEIN> getValues() throws IOException, InterruptedException
IOExceptionInterruptedExceptionCopyright © 2014 Apache Software Foundation. All Rights Reserved.