hyperledger/fabric · error

internal leveldb error while iterating for txids

Error message

internal leveldb error while iterating for txids

What it means

While iterating the txID index range in exportUniqueTxIDs, the LevelDB iterator returned an error (dbItr.Error() != nil). The error is wrapped as an internal leveldb iteration failure; the underlying cause is carried by the wrap.

Source

Thrown at common/ledger/blkstorage/blockindex.go:307

}

func (index *blockIndex) exportUniqueTxIDs(dir string, newHashFunc snapshot.NewHashFunc) (map[string][]byte, error) {
	if !index.isAttributeIndexed(IndexableAttrTxID) {
		return nil, errors.New("transaction IDs not maintained in index")
	}

	dbItr, err := index.db.GetIterator([]byte{txIDIdxKeyPrefix}, []byte{txIDIdxKeyPrefix + 1})
	if err != nil {
		return nil, err
	}
	defer dbItr.Release()

	var previousTxID string
	var numTxIDs uint64 = 0
	var dataFile *snapshot.FileWriter
	for dbItr.Next() {
		if err := dbItr.Error(); err != nil {
			return nil, errors.Wrap(err, "internal leveldb error while iterating for txids")
		}
		txID, err := retrieveTxID(dbItr.Key())
		if err != nil {
			return nil, err
		}
		// duplicate TxID may be present in the index
		if previousTxID == txID {
			continue
		}
		previousTxID = txID
		if numTxIDs == 0 { // first iteration, create the data file
			dataFile, err = snapshot.CreateFile(filepath.Join(dir, snapshotDataFileName), snapshotFileFormat, newHashFunc)
			if err != nil {
				return nil, err
			}
			defer dataFile.Close()
		}
		if err := dataFile.EncodeString(txID); err != nil {

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Inspect the wrapped cause in the error chain for the actual leveldb error (I/O, corruption, closed DB).
2. Check disk space and filesystem health on the ledger data directory.
3. If the index DB is corrupted, rebuild it: stop the peer, remove the index directory, and let the peer reindex or rejoin the channel.
4. Retry snapshot export after the peer has fully started and no other maintenance process holds the DB.

txIDs, err := index.exportUniqueTxIDs(dir, hashFunc)
if err != nil {
    var cause error
    errors.As(err, &cause)
    if errors.Is(cause, syscall.ENOSPC) || errors.Is(cause, syscall.EIO) {
        return fmt.Errorf("storage problem during txID export: %w", cause) // fix disk, then retry
    }
    return err // corruption path: rebuild index instead of retrying
}

When it happens

Trigger: LevelDB underlying store corruption, I/O errors (disk full, permission issues on the index directory), or a store closed/compacting concurrently while the iterator advances during snapshot export.

Common situations: Disk-full or I/O failures on the peer's ledger data volume, corrupted index DB after an unclean shutdown, running snapshot export while another process deletes or repairs the index DB.

Related errors

• error while reading from snapshot file: %s
• error peeking [%d] bytes from block file
• error discarding [%d] bytes
• error reading [%d] bytes from file number [%d]
• error in block index: %s

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/864b9a13d1cfdf15. Report an issue: GitHub.