### Question:
SegmentColumnarIndexCreator implements SegmentCreator { public static void removeColumnMetadataInfo(PropertiesConfiguration properties, String column) { properties.subset(COLUMN_PROPS_KEY_PREFIX + column).clear(); }  @Override void init(SegmentGeneratorConfig segmentCreationSpec, SegmentIndexCreationInfo segmentIndexCreationInfo,
      Map<String, ColumnIndexCreationInfo> indexCreationInfoMap, Schema schema, File outDir); static boolean shouldDeriveNumDocsPerChunk(String columnName,
      Map<String, Map<String, String>> columnProperties); static int rawIndexWriterVersion(String columnName, Map<String, Map<String, String>> columnProperties); @Override void indexRow(GenericRow row); @Override void setSegmentName(String segmentName); @Override void seal(); static void addColumnMetadataInfo(PropertiesConfiguration properties, String column,
      ColumnIndexCreationInfo columnIndexCreationInfo, int totalDocs, FieldSpec fieldSpec, boolean hasDictionary,
      int dictionaryElementSize, boolean hasInvertedIndex, TextIndexType textIndexType); static void addColumnMinMaxValueInfo(PropertiesConfiguration properties, String column, String minValue,
      String maxValue); static void removeColumnMetadataInfo(PropertiesConfiguration properties, String column); static ForwardIndexCreator getRawIndexCreatorForColumn(File file,
      ChunkCompressorFactory.CompressionType compressionType, String column, DataType dataType, int totalDocs,
      int lengthOfLongestEntry, boolean deriveNumDocsPerChunk, int writerVersion); @Override void close();  }### Answer:
@Test public void testRemoveColumnMetadataInfo() throws Exception { PropertiesConfiguration configuration = new PropertiesConfiguration(CONFIG_FILE); configuration.setProperty(COLUMN_PROPERTY_KEY_PREFIX + "a", "foo"); configuration.setProperty(COLUMN_PROPERTY_KEY_PREFIX + "b", "bar"); configuration.setProperty(COLUMN_PROPERTY_KEY_PREFIX + "c", "foobar"); configuration.save(); configuration = new PropertiesConfiguration(CONFIG_FILE); assertTrue(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "a")); assertTrue(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "b")); assertTrue(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "c")); SegmentColumnarIndexCreator.removeColumnMetadataInfo(configuration, COLUMN_NAME); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "a")); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "b")); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "c")); configuration.save(); configuration = new PropertiesConfiguration(CONFIG_FILE); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "a")); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "b")); assertFalse(configuration.containsKey(COLUMN_PROPERTY_KEY_PREFIX + "c")); }