nats-io/nats-server · error

Got an error re-encoding append entry: %v

Error message

Got an error re-encoding append entry: %v

What it means

While re-encoding a log entry for a catching-up follower (rewriting its lterm to the leader's current term), appendEntry.encode failed. This indicates a malformed or internally inconsistent entry buffer, and the send loop for that batch is abandoned.

Source

Thrown at server/raft.go:3674

	sendNext := func() bool {
		for total <= maxOutstanding {
			next++
			if next > last {
				return true
			}
			ae, err := n.loadEntry(next)
			if err != nil {
				if err != ErrStoreEOF {
					n.warn("Got an error loading %d index: %v", next, err)
				}
				return true
			}
			// Re-encode with the lterm if needed
			if ae.lterm != term {
				ae.lterm = term
				if ae.buf, err = ae.encode(ae.buf[:0]); err != nil {
					n.warn("Got an error re-encoding append entry: %v", err)
					return true
				}
			}
			// Update our tracking total.
			om[next] = len(ae.buf)
			total += len(ae.buf)
			n.sendRPC(subj, reply, ae.buf)
		}
		return false
	}

	const activityInterval = 2 * time.Second
	timeout := time.NewTimer(activityInterval)
	defer timeout.Stop()

	stepCheck := time.NewTicker(100 * time.Millisecond)
	defer stepCheck.Stop()

View on GitHub (pinned to 3a66a489d2)

Solutions

1. Capture the error to identify why encode failed (usually a corrupt entry in the WAL)
2. Consider truncating the WAL or re-snapshotting so the offending entry is regenerated
3. Report as a bug if it recurs on valid data

When it happens

Trigger: Thrown at server/raft.go:3674 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of nats-io/nats-server@3a66a489d2 (2026-09-02). Data as JSON: /api/errors/89c2dd8cc9eacd99. Report an issue: GitHub.