apache/hadoop · error · IllegalStateException

Cannot create Data Block until previous block is closed.

Error message

Cannot create Data Block until previous block is closed.

What it means

Error "Cannot create Data Block until previous block is closed." thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/BCFile.java:422

     * @throws IOException
     */
    public BlockAppender prepareMetaBlock(String name) throws IOException,
        MetaBlockAlreadyExists {
      return prepareMetaBlock(name, getDefaultCompressionAlgorithm());
    }

    /**
     * Create a Data Block and obtain an output stream for adding data into the
     * block. There can only be one BlockAppender stream active at any time.
     * Data Blocks may not be created after the first Meta Blocks. The caller
     * must call BlockAppender.close() to conclude the block creation.
     * 
     * @return The BlockAppender stream
     * @throws IOException
     */
    public BlockAppender prepareDataBlock() throws IOException {
      if (blkInProgress == true) {
        throw new IllegalStateException(
            "Cannot create Data Block until previous block is closed.");
      }

      if (metaBlkSeen == true) {
        throw new IllegalStateException(
            "Cannot create Data Block after Meta Blocks.");
      }

      DataBlockRegister dbr = new DataBlockRegister();

      WBlockState wbs =
          new WBlockState(getDefaultCompressionAlgorithm(), out,
              fsOutputBuffer, conf);
      BlockAppender ba = new BlockAppender(dbr, wbs);
      blkInProgress = true;
      return ba;
    }

View on GitHub (pinned to 2add963021)

Solutions

1. Close the previous block appender before creating a new data block.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/BCFile.java:422 when the library encounters an invalid state.

Common situations: Occurs when a new Data Block is started while a previous block is still open. Close the previous block before preparing a new data block.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/955ca03039c31acf. Report an issue: GitHub.