Class VirtualTable

fe/src/main/java/org/apache/impala/catalog/VirtualTable.java:39–158

Tables that aren't actually exist in HMS. E.g. Iceberg position delete tables. Metadata tables can be another use case for this class. Using old table schema and stats during time-travel might be another use case.

 * Using old table schema and stats during time-travel might be another use case.
 */
public abstract class VirtualTable implements FeTable {
  protected final Table msTable_;
  protected final FeDb db_;
  protected final String name_;
  protected final String owner_;

  // colsByPos[i] refers to the ith column in the table. The first numClusteringCols are
  // the clustering columns.
  protected final List<Column> colsByPos_ = new ArrayList<>();

  // map from lowercase column name to Column object.
  protected final Map<String, Column> colsByName_ = new HashMap<>();

  // Number of clustering columns.
  protected int numClusteringCols_ = 0;

  // Type of this table (array of struct) that mirrors the columns. Useful for analysis.
  protected final ArrayType type_ = new ArrayType(new StructType());

  public VirtualTable(org.apache.hadoop.hive.metastore.api.Table msTable, FeDb db,
      String name, String owner) {
    msTable_ = msTable;
    db_ = db;
    name_ = name;
    owner_ = owner;
  }

  protected void addColumn(Column col) {
    colsByPos_.add(col);
    colsByName_.put(col.getName().toLowerCase(), col);
    ((StructType) type_.getItemType()).addField(
        new StructField(col.getName(), col.getType(), col.getComment()));
  }

  @Override
  public String getTableComment() { return null; }

  @Override
  public boolean isLoaded() { return true; }

  @Override
  public Table getMetaStoreTable() { return msTable_; }

  @Override
  public String getStorageHandlerClassName() { return null; }

  @Override
  public TCatalogObjectType getCatalogObjectType() { return TCatalogObjectType.TABLE; }

  @Override
  public TImpalaTableType getTableType() { return TImpalaTableType.TABLE; }

  @Override
  public FeDb getDb() { return db_; }

  @Override
  public String getName() { return name_; }