apache/flink · error · EOFException

Could not skip {numBytes} bytes.

Error message

Could not skip {numBytes} bytes.

What it means

Thrown by DataInputViewStreamWrapper.skipBytesToRead(int) when the underlying InputStream's skipBytes returned fewer bytes than requested, i.e. the stream reached EOF before numBytes could be skipped. This wrapper adapts a blocking InputStream to the DataInputView contract and treats a short skip as a hard EOF.

Source

Thrown at flink-core/src/main/java/org/apache/flink/core/memory/DataInputViewStreamWrapper.java:39

import org.apache.flink.annotation.PublicEvolving;

import java.io.DataInputStream;
import java.io.EOFException;
import java.io.IOException;
import java.io.InputStream;

/** Utility class that turns an {@link InputStream} into a {@link DataInputView}. */
@PublicEvolving
public class DataInputViewStreamWrapper extends DataInputStream implements DataInputView {

    public DataInputViewStreamWrapper(InputStream in) {
        super(in);
    }

    @Override
    public void skipBytesToRead(int numBytes) throws IOException {
        if (skipBytes(numBytes) != numBytes) {
            throw new EOFException("Could not skip " + numBytes + " bytes.");
        }
    }
}

View on GitHub (pinned to 2f3c205e92)

Solutions

1. Confirm the stream contains at least numBytes before skipping (e.g. via available() or a known message length).
2. Ensure the source stream is fully buffered/complete before deserialization.
3. Handle EOFException to detect truncation at the framing layer.

Example fix

// before
view.skipBytesToRead(fieldSize);

// after
try {
    view.skipBytesToRead(fieldSize);
} catch (EOFException e) {
    throw new IOException("Stream truncated while skipping field of " + fieldSize + " bytes", e);
}

// Best-effort: check stream availability before skipping
if (in.available() > 0 && in.available() < numBytes) {
    throw new EOFException("Stream has only " + in.available() + " bytes, need " + numBytes);
}

try {
    view.skipBytesToRead(numBytes);
} catch (EOFException e) {
    throw new IOException("Input stream truncated before " + numBytes + " bytes could be skipped", e);
}

When it happens

Trigger: Calling skipBytesToRead(n) on a DataInputViewStreamWrapper whose backing InputStream has fewer than n bytes remaining (or returns -1).

Common situations: Truncated network stream or file; closed/drained input stream; a record header declaring more skip bytes than the payload contains; reading past the end of a fixed-size message.

Related errors

• Reached the end of the collection. This could be caused by i
• Could not skip {numBytes} bytes.
• Failed to deserialize an element from the source. If you are
• Failed to deserialize an element from the source. If you are
• Unable to deserialize message

AI-assisted analysis of apache/flink@2f3c205e92 (2026-08-14). Data as JSON: /api/errors/0d12f88e02b433f4. Report an issue: GitHub.