Package oracle.kv.hadoop

Class KVInputFormatBase<K,V>

java.lang.Object
org.apache.hadoop.mapreduce.InputFormat<K,V>
oracle.kv.hadoop.KVInputFormatBase<K,V>
Direct Known Subclasses:
KVInputFormat
public abstract class KVInputFormatBase<K,V> extends InputFormat<K,V>
This is the base class for Oracle NoSQL Database InputFormat classes. Keys and Value types are determined by the specific subclass.

Parameters may be passed using either the static setters on this class or through the Hadoop JobContext configuration parameters. The following parameters are recognized:

  • oracle.kv.kvstore - the KV Store name for this InputFormat to operate on. This is equivalent to the setKVStoreName(java.lang.String) method.
  • oracle.kv.hosts - one or more hostname:port pairs separated by commas naming hosts in the KV Store. This is equivalent to the setKVHelperHosts(java.lang.String[]) method.
  • oracle.kv.batchSize - Specifies the suggested number of keys to fetch during each network round trip by the InputFormat. If 0, an internally determined default is used. This is equivalent to the setBatchSize(int) method.
  • oracle.kv.parentKey - Specifies the parent key whose "child" KV pairs are to be returned by the InputFormat. null will result in fetching all keys in the store. If non-null, the major key path must be a partial path and the minor key path must be empty. This is equivalent to the setParentKey(oracle.kv.Key) method.
  • oracle.kv.subRange - Specifies a sub range to further restrict the range under the parentKey to the major path components in this sub range. It may be null. This is equivalent to the setSubRange(oracle.kv.KeyRange) method.
  • oracle.kv.depth - Specifies whether the parent and only children or all descendents are returned. If null, Depth.PARENT_AND_DESCENDENTS is implied. This is equivalent to the setDepth(oracle.kv.Depth) method.
  • oracle.kv.consistency - Specifies the read consistency associated with the lookup of the child KV pairs. Version- and Time-based consistency may not be used. If null, the default consistency is used. This is equivalent to the setConsistency(oracle.kv.Consistency) method.
  • oracle.kv.timeout - Specifies an upper bound on the time interval for processing a particular KV retrieval. A best effort is made to not exceed the specified limit. If zero, the default request timeout is used. This value is always in milliseconds. This is equivalent to the setTimeout(long) and setTimeoutUnit(java.util.concurrent.TimeUnit) methods.

Internally, the KVInputFormatBase class utilizes KVStore.storeIterator to retrieve records. You should refer to the javadoc for that method for information about the various parameters.

KVInputFormatBase creates one split per Oracle NoSQL DB partition. The location value for each split is an array of hosts holding the partition. If the consistency passed to KVInputFormatBase is NONE_REQUIRED (the default), then InputSplit.getLocations() will return an array of the names of the master and the replica(s) which contain the partition. Alternatively, if the consistency is NONE_REQUIRED_NO_MASTER, then the array returned will contain only the names of the replica(s); not the master. Finally, if the consistency is ABSOLUTE, then the array returned will contain only the name of the master. This means that if Hadoop job trackers are running on the nodes named in the returned location array, Hadoop will generally attempt to run the subtasks for a particular partition on those nodes where the data is stored and replicated. Hadoop and Oracle NoSQL DB administrators should be careful about co-location of Oracle NoSQL DB and Hadoop processes since they may compete for resources.

Partitions in Oracle NoSQL DB are considered to be roughly equal in size; therefore InputSplit.getLength() always returns 1.

A simple example demonstrating the Oracle NoSQL DB Hadoop oracle.kv.hadoop.InputFormat class reading data from Hadoop in a Map/Reduce job and counting the number of records for each major key in the store can be found in the KVHOME/examples/hadoop directory. The javadoc for that program describes the simple Map/Reduce processing as well as how to invoke the program in Hadoop.

Since:
2.0

  • Method Summary

    Modifier and Type
    Method
    Description
    static void
    setBatchSize(int batchSize)
    Specifies the suggested number of keys to fetch during each network round trip by the InputFormat.
    static void
    setConsistency(Consistency consistency)
    Specifies the read consistency associated with the lookup of the child KV pairs.
    static void
    setDepth(Depth depth)
    Specifies whether the parent and only children or all descendents are returned.
    static void
    setKVHelperHosts(String[] kvHelperHosts)
    Set the KV Helper host:port pair(s) for this InputFormat to operate on.
    static void
    setKVSecurity(String kvStoreSecurity)
    Allows KVStore security to be set.
    static void
    setKVStoreName(String kvStoreName)
    Set the KV Store name for this InputFormat to operate on.
    static void
    setParentKey(Key parentKey)
    Specifies the parent key whose "child" KV pairs are to be returned by the InputFormat.
    static void
    setSubRange(KeyRange subRange)
    Specifies a sub range to further restrict the range under the parentKey to the major path components in this sub range.
    static void
    setTimeout(long timeout)
    Specifies an upper bound on the time interval for processing a particular KV retrieval.
    static void
    setTimeoutUnit(TimeUnit timeoutUnit)
    Specifies the unit of the timeout parameter.

    Methods inherited from class org.apache.hadoop.mapreduce.InputFormat

    createRecordReader

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Method Details

    • setKVStoreName

      public static void setKVStoreName(String kvStoreName)
      Set the KV Store name for this InputFormat to operate on. This is equivalent to passing the oracle.kv.kvstore Hadoop property.
      Parameters:
      kvStoreName - the KV Store name

    • setKVHelperHosts

      public static void setKVHelperHosts(String[] kvHelperHosts)
      Set the KV Helper host:port pair(s) for this InputFormat to operate on. This is equivalent to passing the oracle.kv.hosts Hadoop property.
      Parameters:
      kvHelperHosts - array of hostname:port strings of any hosts in the KV Store.

    • setBatchSize

      public static void setBatchSize(int batchSize)
      Specifies the suggested number of keys to fetch during each network round trip by the InputFormat. If 0, an internally determined default is used. This is equivalent to passing the oracle.kv.batchSize Hadoop property.
      Parameters:
      batchSize - the suggested number of keys to fetch during each network round trip.

    • setParentKey

      public static void setParentKey(Key parentKey)
      Specifies the parent key whose "child" KV pairs are to be returned by the InputFormat. null will result in fetching all keys in the store. If non-null, the major key path must be a partial path and the minor key path must be empty. This is equivalent to passing the oracle.kv.parentKey Hadoop property.
      Parameters:
      parentKey - the parentKey

    • setSubRange

      public static void setSubRange(KeyRange subRange)
      Specifies a sub range to further restrict the range under the parentKey to the major path components in this sub range. It may be null. This is equivalent to passing the oracle.kv.subRange Hadoop property.
      Parameters:
      subRange - the sub range.

    • setDepth

      public static void setDepth(Depth depth)
      Specifies whether the parent and only children or all descendents are returned. If null, Depth.PARENT_AND_DESCENDENTS is implied. This is equivalent to passing the oracle.kv.depth Hadoop property.
      Parameters:
      depth - the depth.

    • setConsistency

      public static void setConsistency(Consistency consistency)
      Specifies the read consistency associated with the lookup of the child KV pairs. Version- and Time-based consistency may not be used. If null, the default consistency is used. This is equivalent to passing the oracle.kv.consistency Hadoop property.
      Parameters:
      consistency - the consistency

    • setTimeout

      public static void setTimeout(long timeout)
      Specifies an upper bound on the time interval for processing a particular KV retrieval. A best effort is made to not exceed the specified limit. If zero, the default request timeout is used. This is equivalent to passing the oracle.kv.timeout Hadoop property.
      Parameters:
      timeout - the timeout

    • setTimeoutUnit

      public static void setTimeoutUnit(TimeUnit timeoutUnit)
      Specifies the unit of the timeout parameter. It may be null only if timeout is zero. This is equivalent to passing the oracle.kv.timeout Hadoop property.
      Parameters:
      timeoutUnit - the timeout unit

    • setKVSecurity

      public static void setKVSecurity(String kvStoreSecurity)
      Allows KVStore security to be set. The kvStoreSecurity file is a property file utilizing the format supported by the CLI tools. This security file and any wallet or password store needed to support it must be distributed on the hadoop cluster.
      Since:
      3.0