apache/iceberg · error · UnsupportedOperationException

does not implement getMap

Error message

${this.getClass()} does not implement getMap

What it means

ConstantColumnVector stores a single repeated constant value and implements only scalar accessors. getMap is intentionally unimplemented and always throws UnsupportedOperationException, because a constant value cannot be a map. Spark calls getMap when the reader expects a map-typed column but the vector is a constant vector.

Solutions

1. Check the partition spec / projection for a map-typed constant field and change the table design (partition by a scalar key instead of the map).
2. Turn off vectorized reads (read.vectorization.enabled=false) to bypass ConstantColumnVector and use the row-based reader.
3. If support is genuinely needed, implement getMap in ConstantColumnVector returning a constant ColumnarMap.
4. Upgrade Iceberg to a release where this path is guarded or supported.

if (vector instanceof ConstantColumnVector && expectedType instanceof MapType) {
  throw new IllegalStateException("Constant projection cannot yield a map column");
}

boolean supportsMaps(ColumnVector v) { return !(v instanceof ConstantColumnVector); }

try { vector.getMap(rowId); } catch (UnsupportedOperationException e) {
  // re-read column via non-vectorized path
}

When it happens

Trigger: Reading a map-typed column that the scan resolved to a constant vector — e.g. a map-typed partition column, a constant-folded expression returning a map, or metadata column projection producing a constant map.

Common situations: Map-typed partition fields in the table spec (unsupported for constant projection); queries referencing map columns under predicates that Iceberg constant-folds; version mismatches where Spark's vectorized reader assumes map support.

Related errors

• does not implement getArray
• Unhandled type
• Unsupported type - byte
• Unsupported type - byte
• Unsupported type - short

AI-assisted analysis of apache/iceberg@86d9c8fc54 (2026-09-12). Data as JSON: /api/errors/395284f4045360e0. Report an issue: GitHub.

Appendix: source

Thrown at spark/v4.2/spark/src/main/java/org/apache/iceberg/spark/data/vectorized/ConstantColumnVector.java:107

  @Override
  public float getFloat(int rowId) {
    return (float) constant;
  }

  @Override
  public double getDouble(int rowId) {
    return (double) constant;
  }

  @Override
  public ColumnarArray getArray(int rowId) {
    throw new UnsupportedOperationException(this.getClass() + " does not implement getArray");
  }

  @Override
  public ColumnarMap getMap(int ordinal) {
    throw new UnsupportedOperationException(this.getClass() + " does not implement getMap");
  }

  @Override
  public Decimal getDecimal(int rowId, int precision, int scale) {
    return (Decimal) constant;
  }

  @Override
  public UTF8String getUTF8String(int rowId) {
    return (UTF8String) constant;
  }

  @Override
  public byte[] getBinary(int rowId) {
    return (byte[]) constant;
  }

  @Override

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