{"record":{"id":"63bfcd90ea7465c2","repo":"apache/hadoop","slug":"cannot-create-data-block-after-meta-blocks","errorCode":null,"errorMessage":"Cannot create Data Block after Meta Blocks.","messagePattern":"Cannot create Data Block after Meta Blocks\\.","errorType":"exception","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/BCFile.java","lineNumber":427,"sourceCode":"    }\n\n    /**\n     * Create a Data Block and obtain an output stream for adding data into the\n     * block. There can only be one BlockAppender stream active at any time.\n     * Data Blocks may not be created after the first Meta Blocks. The caller\n     * must call BlockAppender.close() to conclude the block creation.\n     * \n     * @return The BlockAppender stream\n     * @throws IOException\n     */\n    public BlockAppender prepareDataBlock() throws IOException {\n      if (blkInProgress == true) {\n        throw new IllegalStateException(\n            \"Cannot create Data Block until previous block is closed.\");\n      }\n\n      if (metaBlkSeen == true) {\n        throw new IllegalStateException(\n            \"Cannot create Data Block after Meta Blocks.\");\n      }\n\n      DataBlockRegister dbr = new DataBlockRegister();\n\n      WBlockState wbs =\n          new WBlockState(getDefaultCompressionAlgorithm(), out,\n              fsOutputBuffer, conf);\n      BlockAppender ba = new BlockAppender(dbr, wbs);\n      blkInProgress = true;\n      return ba;\n    }\n\n    /**\n     * Callback to make sure a meta block is added to the internal list when its\n     * stream is closed.\n     */\n    private class MetaBlockRegister implements BlockRegister {","sourceCodeStart":409,"sourceCodeEnd":445,"githubUrl":"https://github.com/apache/hadoop/blob/2add9630210752f88ceb1bb74eb65e37bf41da8e/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/BCFile.java#L409-L445","documentation":"Error \"Cannot create Data Block after Meta Blocks.\" thrown in apache/hadoop.","triggerScenarios":"Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/file/tfile/BCFile.java:427 when the library encounters an invalid state.","commonSituations":"Occurs when a Data Block is created after Meta Blocks have been written. Write all data blocks before any meta blocks in a BCFile.","solutions":["Write all data blocks before any meta blocks; BCFile requires data blocks first, meta blocks after."],"exampleFix":null,"handlingStrategy":null,"validationCode":null,"typeGuard":null,"tryCatchPattern":null,"preventionTips":[],"tags":[],"backgroundTag":null,"analyzedSha":"2add9630210752f88ceb1bb74eb65e37bf41da8e","analyzedAt":"2026-08-22T19:55:07.957Z","schemaVersion":2},"datasetVersion":"2026-08-22T20:17:22.307Z"}