{"record":{"id":"601a7b71e1f3ccb3","repo":"hyperledger/fabric","slug":"internal-leveldb-error-while-retrieving-data-from","errorCode":null,"errorMessage":"internal leveldb error while retrieving data from db iterator","messagePattern":"internal leveldb error while retrieving data from db iterator","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"common/ledger/util/leveldbhelper/leveldb_provider.go","lineNumber":231,"sourceCode":"func (h *DBHandle) deleteAll() error {\n\titer, err := h.GetIterator(nil, nil)\n\tif err != nil {\n\t\treturn err\n\t}\n\tdefer iter.Release()\n\n\t// use leveldb iterator directly to be more efficient\n\tdbIter := iter.Iterator\n\n\t// This is common code shared by all the leveldb instances. Because each leveldb has its own key size pattern,\n\t// each batch is limited by memory usage instead of number of keys. Once the batch memory usage reaches maxBatchSize,\n\t// the batch will be committed.\n\tnumKeys := 0\n\tbatchSize := 0\n\tbatch := &leveldb.Batch{}\n\tfor dbIter.Next() {\n\t\tif err := dbIter.Error(); err != nil {\n\t\t\treturn errors.Wrap(err, \"internal leveldb error while retrieving data from db iterator\")\n\t\t}\n\t\tkey := dbIter.Key()\n\t\tnumKeys++\n\t\tbatchSize = batchSize + len(key)\n\t\tbatch.Delete(key)\n\t\tif batchSize >= maxBatchSize {\n\t\t\tif err := h.db.WriteBatch(batch, true); err != nil {\n\t\t\t\treturn err\n\t\t\t}\n\t\t\tlogger.Infof(\"Have removed %d entries for channel %s in leveldb %s\", numKeys, h.dbName, h.db.conf.DBPath)\n\t\t\tbatchSize = 0\n\t\t\tbatch.Reset()\n\t\t}\n\t}\n\tif batch.Len() > 0 {\n\t\treturn h.db.WriteBatch(batch, true)\n\t}\n\treturn nil","sourceCodeStart":213,"sourceCodeEnd":249,"githubUrl":"https://github.com/hyperledger/fabric/blob/2736b63f8fd5932511d56fe68b7039d15977f7f6/common/ledger/util/leveldbhelper/leveldb_provider.go#L213-L249","documentation":"During deleteAll, the code iterates over all keys in a handle's namespace to build a delete batch. If the underlying LevelDB iterator reports an error mid-iteration (dbIter.Error() after Next()), the delete is aborted and this wrapped error is returned. It indicates the scan itself failed, so data was NOT fully deleted.","triggerScenarios":"Calling DeleteAll/Close on a DBHandle while the internal iterator hits a LevelDB read error — corrupted SST files, missing MANIFEST, I/O failure during compaction/scan, or a snapshot inconsistency. Any dbIter.Next() followed by a non-nil dbIter.Error() in deleteAll produces it.","commonSituations":"Corrupted ledger database after unclean shutdown or disk-full during writes; hardware/IO errors while the node deletes a namespace's data; version/file-lock issues leaving the DB in a bad state during cleanup at shutdown.","solutions":["Read the wrapped LevelDB cause in the error chain and fix it (missing/corrupt files, I/O errors)","Stop the process, back up the DB directory, and attempt leveldb recovery or restore from snapshot/backup","Check disk space and filesystem health (dmesg, SMART) before retrying deletion","If corruption is unrecoverable, recreate the ledger data directory and resync from peers/snapshot"],"exampleFix":"// before\nerr := dbHandle.DeleteAll() // returns wrapped iterator error\n// after: inspect cause and recover\nif err := dbHandle.DeleteAll(); err != nil {\n\tlog.Errorf(\"deleteAll failed: %v\", errors.Unwrap(err))\n\t// restore from backup or resync before retrying\n}","handlingStrategy":"try-catch","validationCode":"if _, err := os.Stat(dbPath); err != nil { return fmt.Errorf(\"db path missing: %w\", err) }\nif err := checkDiskSpace(dbPath, minFree); err != nil { return err }","typeGuard":"func isLevelDBIteratorError(err error) bool {\n\treturn err != nil && strings.Contains(err.Error(), \"internal leveldb error while retrieving data\")\n}","tryCatchPattern":"err := handle.DeleteAll()\nvar wrapped error\nif errors.As(err, &wrapped) {\n\tcause := errors.Unwrap(err)\n\tlog.Errorf(\"underlying leveldb failure: %v\", cause)\n\t// trigger backup/restore or resync path\n}","preventionTips":["Monitor disk space and I/O health on ledger volumes","Back up ledger directories before delete/close operations","Avoid killing the process during compaction/writes to prevent corruption","Surface errors.Unwrap(err) in logs to identify the root leveldb cause"],"tags":["leveldb","iterator","corruption","database"],"backgroundTag":"leveldb-iterator-error","analyzedSha":"2736b63f8fd5932511d56fe68b7039d15977f7f6","analyzedAt":"2026-09-04T08:52:36.465Z","contentChangedAt":"2026-09-04T08:52:36.465Z","schemaVersion":2},"datasetVersion":"2026-09-08T10:18:20.063Z"}