dgraph-io/badger · critical

Ptrs and Entries don't match: %+v

Error message

Ptrs and Entries don't match: %+v

What it means

writeToLSM verifies that each write request's entry list and its corresponding vlog pointer list are the same length, since every entry must map to exactly one pointer. A mismatch is an internal invariant violation, skipped only in InMemory mode where no pointers are produced.

Source

Thrown at db.go:829

		if maxVs.Version < vs.Version {
			maxVs = vs
		}
	}
	return db.lc.get(key, maxVs, 0)
}

var requestPool = sync.Pool{
	New: func() interface{} {
		return new(request)
	},
}

func (db *DB) writeToLSM(b *request) error {
	// We should check the length of b.Prts and b.Entries only when badger is not
	// running in InMemory mode. In InMemory mode, we don't write anything to the
	// value log and that's why the length of b.Ptrs will always be zero.
	if !db.opt.InMemory && len(b.Ptrs) != len(b.Entries) {
		return fmt.Errorf("Ptrs and Entries don't match: %+v", b)
	}

	for i, entry := range b.Entries {
		var err error
		if entry.skipVlogAndSetThreshold(db.valueThreshold()) {
			// Will include deletion / tombstone case.
			err = db.mt.Put(entry.Key,
				y.ValueStruct{
					Value: entry.Value,
					// Ensure value pointer flag is removed. Otherwise, the value will fail
					// to be retrieved during iterator prefetch. `bitValuePointer` is only
					// known to be set in write to LSM when the entry is loaded from a backup
					// with lower ValueThreshold and its value was stored in the value log.
					Meta:      entry.meta &^ bitValuePointer,
					UserMeta:  entry.UserMeta,
					ExpiresAt: entry.ExpiresAt,
				})
		} else {

View on GitHub (pinned to 2a001d466f)

Solutions

1. Report/fix the bug in the code constructing the request so len(Ptrs) == len(Entries)
2. Never mutate b.Ptrs or b.Entries after submitting to writeRequests
3. Upgrade badger — if hit on stock write APIs, it is a library bug

if len(req.Ptrs) != len(req.Entries) {
    return fmt.Errorf("bad request: %d ptrs vs %d entries", len(req.Ptrs), len(req.Entries))
}

func requestSane(r *request) bool { return len(r.Ptrs) == len(r.Entries) || inMemoryMode }

if err := db.writeToLSM(req); err != nil {
    if strings.Contains(err.Error(), "Ptrs and Entries don't match") {
        log.Fatalf("internal bug: dump req entries=%d ptrs=%d", len(req.Entries), len(req.Ptrs))
    }
}

When it happens

Trigger: Writing via db.Write, db.Commit, or writeRequests where the request's Ptrs and Entries slices diverged — effectively only reachable from internal bugs or custom code constructing request structs directly (e.g. in forks/tests).

Common situations: Patching badger internals or building manual write requests; concurrency bugs in code that mutates a request between vlog write and LSM write; InMemory mismatch confusion.

Understand the failure class

Background: "This is a bug, please report it": internal invariant violations, unreachable panics, and SNH errors explained — this error's family across 47 libraries.

Related errors

• errNoMerge
• keyRange not found
• ErrValueLogSize
• ErrKeyNotFound
• ErrTxnTooBig

AI-assisted analysis of dgraph-io/badger@2a001d466f (2026-09-05). Data as JSON: /api/errors/87e130d97c818bf6. Report an issue: GitHub.