apache/druid · error · ResponseException

error closing org.apache.druid.query.aggregation.Serializabl

Error message

error closing org.apache.druid.query.aggregation.SerializablePairLongLongComplexColumn

What it means

SerializablePairLongLongComplexColumn.close() releases resources through a Closer; if closing the wrapped Closeable throws IOException it is rethrown as a Druid RE with 'error closing <class name>'. This indicates cleanup of the serialized pair-long-long column failed, risking leaked file handles or mapped memory.

Source

Thrown at processing/src/main/java/org/apache/druid/query/aggregation/SerializablePairLongLongComplexColumn.java:86

  public Object getRowValue(int rowNum)
  {
    return serde.deserialize(cellReader.getCell(rowNum));
  }

  @Override
  public int getLength()
  {
    return serializedSize;
  }

  @Override
  public void close()
  {
    try {
      closer.close();
    }
    catch (IOException e) {
      throw new RE(e, "error closing " + getClass().getName());
    }
  }

  public static class Builder
  {
    private final int serializedSize;
    private final AbstractSerializablePairLongObjectDeltaEncodedStagedSerde<?> serde;
    private final CellReader.Builder cellReaderBuilder;

    public Builder(ByteBuffer buffer)
    {
      ByteBuffer masterByteBuffer = buffer.asReadOnlyBuffer().order(ByteOrder.nativeOrder());

      serializedSize = masterByteBuffer.remaining();

      AbstractSerializablePairLongObjectColumnHeader<?> columnHeader =
          AbstractSerializablePairLongObjectColumnHeader.fromBuffer(masterByteBuffer, SerializablePairLongLong.class);

View on GitHub (pinned to 9b90983fd2)

Solutions

Inspect the wrapped IOException cause and address the underlying close failure (file, channel, or filesystem state)
Ensure single-owner closing — don't close the underlying resource both manually and via the Closer
Verify segment file lifecycle ordering so the column closes before its backing files are cleaned up
Check disk/filesystem health and permissions on the segment directory

Example fix

// before
closer.close(); // IOException propagates as RE
// after
try {
  closer.close();
} catch (IOException e) {
  LOG.warn(e, "error closing %s", getClass().getName());
}

Defensive patterns

Strategy: try-catch

Try / catch

try {
  column.close();
} catch (RE e) {
  if (e.getCause() instanceof IOException) {
    LOG.warn(e, "failed to close SerializablePairLongLongComplexColumn");
  } else {
    throw e;
  }
}

Prevention

Ensure single-owner resource lifecycle; don't double-close registered Closeables
Close the column before segment files are removed from disk
Inspect RE causes to distinguish harmless already-closed cases from real I/O problems
Gracefully shut down tasks/queries so cleanup paths complete normally

When it happens

Trigger: close() called when the underlying Closeable (channel/mapped file backing the serialized column) throws IOException on close.

Common situations: Underlying segment file already closed/deleted during query cleanup races; NFS/disk errors; double-close of the same channel; abrupt task termination leaving descriptors in a bad state.

Related errors

AI-assisted analysis of apache/druid@9b90983fd2 (2026-09-07). Data as JSON: /api/errors/db3684954a218fd1. Report an issue: GitHub.