org.apache.spark.sql.execution.streaming

HDFSMetadataLog

class HDFSMetadataLog[T] extends MetadataLog[T] with Logging

A MetadataLog implementation based on HDFS. HDFSMetadataLog uses the specified path as the metadata storage.

When writing a new batch, HDFSMetadataLog will firstly write to a temp file and then rename it to the final batch file. If the rename step fails, there must be multiple writers and only one of them will succeed and the others will fail.

Note: HDFSMetadataLog doesn't support S3-like file systems as they don't guarantee listing files in a directory always shows the latest files.

Linear Supertypes
Logging, MetadataLog[T], AnyRef, Any
Known Subclasses
CompactibleFileStreamLog, FileStreamSinkLog, FileStreamSourceLog
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Inherited
  1. HDFSMetadataLog
  2. Logging
  3. MetadataLog
  4. AnyRef
  5. Any
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  1. Public
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Instance Constructors

  1. new HDFSMetadataLog(sparkSession: SparkSession, path: String)(implicit arg0: ClassTag[T])

Value Members

  1. final def !=(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  2. final def !=(arg0: Any): Boolean

    Definition Classes
    Any

  3. final def ##(): Int

    Definition Classes
    AnyRef → Any

  4. final def ==(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  5. final def ==(arg0: Any): Boolean

    Definition Classes
    Any

  6. def add(batchId: Long, metadata: T): Boolean

    Store the metadata for the specified batchId and return true if successful.

    Store the metadata for the specified batchId and return true if successful. If the batchId's metadata has already been stored, this method will return false.

    Note that this method must be called on a org.apache.spark.util.UninterruptibleThread so that interrupts can be disabled while writing the batch file. This is because there is a potential dead-lock in Hadoop "Shell.runCommand" before 2.5.0 (HADOOP-10622). If the thread running "Shell.runCommand" is interrupted, then the thread can get deadlocked. In our case, writeBatch creates a file using HDFS API and calls "Shell.runCommand" to set the file permissions, and can get deadlocked if the stream execution thread is stopped by interrupt. Hence, we make sure that this method is called on UninterruptibleThread which allows us to disable interrupts here. Also see SPARK-14131.

    Definition Classes
    HDFSMetadataLog → MetadataLog

  7. final def asInstanceOf[T0]: T0

    Definition Classes
    Any

  8. def batchIdToPath(batchId: Long): Path

    Attributes
    protected

  9. def clone(): AnyRef

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  10. def deserialize(in: InputStream): T

    Attributes
    protected

  11. final def eq(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  12. def equals(arg0: Any): Boolean

    Definition Classes
    AnyRef → Any

  13. val fileManager: FileManager

    Attributes
    protected

  14. def finalize(): Unit

    Attributes
    protected[java.lang]
    Definition Classes
    AnyRef
    Annotations
    @throws( classOf[java.lang.Throwable] )

  15. def get(startId: Option[Long], endId: Option[Long]): Array[(Long, T)]

    Return metadata for batches between startId (inclusive) and endId (inclusive).

    Return metadata for batches between startId (inclusive) and endId (inclusive). If startId is None, just return all batches before endId (inclusive).

    Definition Classes
    HDFSMetadataLog → MetadataLog

  16. def get(batchId: Long): Option[T]

    Return the metadata for the specified batchId if it's stored.

    Return the metadata for the specified batchId if it's stored. Otherwise, return None.

    Definition Classes
    HDFSMetadataLog → MetadataLog

  17. final def getClass(): Class[_]

    Definition Classes
    AnyRef → Any

  18. def getLatest(): Option[(Long, T)]

    Return the latest batch Id and its metadata if exist.

    Return the latest batch Id and its metadata if exist.

    Definition Classes
    HDFSMetadataLog → MetadataLog

  19. def hashCode(): Int

    Definition Classes
    AnyRef → Any

  20. def initializeLogIfNecessary(isInterpreter: Boolean): Unit

    Attributes
    protected
    Definition Classes
    Logging

  21. def isBatchFile(path: Path): Boolean

    Attributes
    protected

  22. final def isInstanceOf[T0]: Boolean

    Definition Classes
    Any

  23. def isTraceEnabled(): Boolean

    Attributes
    protected
    Definition Classes
    Logging

  24. def log: Logger

    Attributes
    protected
    Definition Classes
    Logging

  25. def logDebug(msg: ⇒ String, throwable: Throwable): Unit

    Attributes
    protected
    Definition Classes
    Logging

  26. def logDebug(msg: ⇒ String): Unit

    Attributes
    protected
    Definition Classes
    Logging

  27. def logError(msg: ⇒ String, throwable: Throwable): Unit

    Attributes
    protected
    Definition Classes
    Logging

  28. def logError(msg: ⇒ String): Unit

    Attributes
    protected
    Definition Classes
    Logging

  29. def logInfo(msg: ⇒ String, throwable: Throwable): Unit

    Attributes
    protected
    Definition Classes
    Logging

  30. def logInfo(msg: ⇒ String): Unit

    Attributes
    protected
    Definition Classes
    Logging

  31. def logName: String

    Attributes
    protected
    Definition Classes
    Logging

  32. def logTrace(msg: ⇒ String, throwable: Throwable): Unit

    Attributes
    protected
    Definition Classes
    Logging

  33. def logTrace(msg: ⇒ String): Unit

    Attributes
    protected
    Definition Classes
    Logging

  34. def logWarning(msg: ⇒ String, throwable: Throwable): Unit

    Attributes
    protected
    Definition Classes
    Logging

  35. def logWarning(msg: ⇒ String): Unit

    Attributes
    protected
    Definition Classes
    Logging

  36. val metadataPath: Path

  37. final def ne(arg0: AnyRef): Boolean

    Definition Classes
    AnyRef

  38. final def notify(): Unit

    Definition Classes
    AnyRef

  39. final def notifyAll(): Unit

    Definition Classes
    AnyRef

  40. def pathToBatchId(path: Path): Long

    Attributes
    protected

  41. def purge(thresholdBatchId: Long): Unit

    Removes all the log entry earlier than thresholdBatchId (exclusive).

    Removes all the log entry earlier than thresholdBatchId (exclusive).

    Definition Classes
    HDFSMetadataLog → MetadataLog

  42. def serialize(metadata: T, out: OutputStream): Unit

    Attributes
    protected

  43. final def synchronized[T0](arg0: ⇒ T0): T0

    Definition Classes
    AnyRef

  44. def toString(): String

    Definition Classes
    AnyRef → Any

  45. final def wait(): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  46. final def wait(arg0: Long, arg1: Int): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

  47. final def wait(arg0: Long): Unit

    Definition Classes
    AnyRef
    Annotations
    @throws( ... )

Inherited from Logging

Inherited from MetadataLog[T]

Inherited from AnyRef

Inherited from Any

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