Package org.apache.hadoop.hbase.io.hfile

Interface HFileBlock.FSReader

All Known Implementing Classes:
HFileBlock.FSReaderImpl
Enclosing class:
HFileBlock
static interface HFileBlock.FSReader
An HFile block reader with iteration ability.

  • Method Details

    • readBlockData

      HFileBlock readBlockData(long offset, long onDiskSize, boolean pread, boolean updateMetrics, boolean intoHeap) throws IOException
      Reads the block at the given offset in the file with the given on-disk size and uncompressed size.
      Parameters:
      offset - of the file to read
      onDiskSize - the on-disk size of the entire block, including all applicable headers, or -1 if unknown
      pread - true to use pread, otherwise use the stream read.
      updateMetrics - update the metrics or not.
      intoHeap - allocate the block's ByteBuff by ByteBuffAllocator or JVM heap. For LRUBlockCache, we must ensure that the block to cache is an heap one, because the memory occupation is based on heap now, also for CombinedBlockCache, we use the heap LRUBlockCache as L1 cache to cache small blocks such as IndexBlock or MetaBlock for faster access. So introduce an flag here to decide whether allocate from JVM heap or not so that we can avoid an extra off-heap to heap memory copy when using LRUBlockCache. For most cases, we known what's the expected block type we'll read, while for some special case (Example: HFileReaderImpl#readNextDataBlock()), we cannot pre-decide what's the expected block type, then we can only allocate block's ByteBuff from ByteBuffAllocator firstly, and then when caching it in LruBlockCache we'll check whether the ByteBuff is from heap or not, if not then we'll clone it to an heap one and cache it.
      Returns:
      the newly read block
      Throws:
      IOException

    • blockRange

      HFileBlock.BlockIterator blockRange(long startOffset, long endOffset)
      Creates a block iterator over the given portion of the HFile. The iterator returns blocks starting with offset such that offset <= startOffset < endOffset. Returned blocks are always unpacked. Used when no hfile index available; e.g. reading in the hfile index blocks themselves on file open.
      Parameters:
      startOffset - the offset of the block to start iteration with
      endOffset - the offset to end iteration at (exclusive)
      Returns:
      an iterator of blocks between the two given offsets

    • closeStreams

      void closeStreams() throws IOException
      Closes the backing streams
      Throws:
      IOException

    • getBlockDecodingContext

      HFileBlockDecodingContext getBlockDecodingContext()
      Get a decoder for BlockType.ENCODED_DATA blocks from this file.

    • getDefaultBlockDecodingContext

      HFileBlockDecodingContext getDefaultBlockDecodingContext()
      Get the default decoder for blocks from this file.

    • setIncludesMemStoreTS

      void setIncludesMemStoreTS(boolean includesMemstoreTS)

    • setDataBlockEncoder

      void setDataBlockEncoder(HFileDataBlockEncoder encoder, org.apache.hadoop.conf.Configuration conf)

    • unbufferStream

      void unbufferStream()
      To close the stream's socket. Note: This can be concurrently called from multiple threads and implementation should take care of thread safety.