apache/iceberg · error · UnsupportedOperationException

readIntegers is not supported

Error message

readIntegers is not supported

What it means

readIntegers(total, vec, rowId) is a batch-read default method on VectorizedValuesReader that throws UnsupportedOperationException. Concrete vectorized readers override it to bulk-decode integers directly into an Arrow IntVector. Reaching the default means nextVals() batch dispatch selected a reader class that never implemented the integer batch path.

Source

Thrown at arrow/src/main/java/org/apache/iceberg/arrow/vectorized/parquet/VectorizedValuesReader.java:85

  }

  /** Read a single double */
  default double readDouble() {
    throw new UnsupportedOperationException("readDouble is not supported");
  }

  /**
   * Read binary data of some length
   *
   * @param len The number of bytes to read
   */
  default Binary readBinary(int len) {
    throw new UnsupportedOperationException("readBinary is not supported");
  }

  /** Read `total` integers into `vec` starting at `vec[rowId]` */
  default void readIntegers(int total, FieldVector vec, int rowId) {
    throw new UnsupportedOperationException("readIntegers is not supported");
  }

  /** Read `total` longs into `vec` starting at `vec[rowId]` */
  default void readLongs(int total, FieldVector vec, int rowId) {
    throw new UnsupportedOperationException("readLongs is not supported");
  }

  /** Read `total` floats into `vec` starting at `vec[rowId]` */
  default void readFloats(int total, FieldVector vec, int rowId) {
    throw new UnsupportedOperationException("readFloats is not supported");
  }

  /** Read `total` doubles into `vec` starting at `vec[rowId]` */
  default void readDoubles(int total, FieldVector vec, int rowId) {
    throw new UnsupportedOperationException("readDoubles is not supported");
  }

  /**

View on GitHub (pinned to 86d9c8fc54)

Solutions

  1. Disable vectorized reads (read.arrow.enabled=false) to avoid the batch vectorized path.
  2. Upgrade Iceberg for vectorized batch support for this type/encoding.
  3. Implement readIntegers() in the concrete reader, filling vec[rowId..rowId+total).

Example fix

// before
// default readIntegers throws
// after
@Override
public void readIntegers(int total, FieldVector vec, int rowId) {
  for (int i = 0; i < total; i++) ((IntVector) vec).setSafe(rowId + i, readInteger());
}
Defensive patterns

Strategy: try-catch

Validate before calling

// precheck column type before batch vectorized scan
boolean isInt = columnType.equals(Types.IntegerType.get());
if (!isInt) throw new IllegalStateException("batch int read requested for non-int column");

Try / catch

try {
  scan = table.newScan().includeColumnStats();
  tasks = Tasks.foreach(tasks)
} catch (UnsupportedOperationException e) {
  // fall back: rerun with read.arrow.enabled=false
  props.put("read.arrow.enabled", "false");
}

Prevention

When it happens

Trigger: VectorizedPageReader.nextVals(total) calls readIntegers(total, vec, rowId) to fill an Arrow integer vector in bulk, but the active reader subclass does not override the batch integer method (e.g. it only implements per-value reads).

Common situations: Scanning INT columns with vectorized reads enabled where the reader falls back to a base implementation; dictionary-encoded or delta-encoded pages whose reader omits the batch path; custom or older reader implementations.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/5b8bc4fc6afecce4. Report an issue: GitHub.