Function metadataQueryRange

pkg/ingester/ingester.go:3744–3774

metadataQueryRange returns the best range to query for metadata queries based on the timerange in the ingester.

(queryStart, queryEnd int64, db *userTSDB, queryIngestersWithin time.Duration)

// metadataQueryRange returns the best range to query for metadata queries based on the timerange in the ingester.
func metadataQueryRange(queryStart, queryEnd int64, db *userTSDB, queryIngestersWithin time.Duration) (mint, maxt int64, err error) {
	if queryIngestersWithin > 0 {
		// If the feature for querying metadata from store-gateway is enabled,
		// then we don't want to manipulate the mint and maxt.
		return queryStart, queryEnd, nil
	}

	// Ingesters are run with limited retention and we don't support querying the store-gateway for labels yet.
	// This means if someone loads a dashboard that is outside the range of the ingester, and we only return the
	// data for the timerange requested (which will be empty), the dashboards will break. To fix this we should
	// return the "head block" range until we can query the store-gateway.

	// Now the question would be what to do when the query is partially in the ingester range. I would err on the side
	// of caution and query the entire db, as I can't think of a good way to query the head + the overlapping range.
	mint, maxt = queryStart, queryEnd

	lowestTs, err := db.StartTime()
	if err != nil {
		return mint, maxt, err
	}

	// Completely outside.
	if queryEnd < lowestTs {
		mint, maxt = db.Head().MinTime(), db.Head().MaxTime()
	} else if queryStart < lowestTs {
		// Partially inside.
		mint, maxt = 0, math.MaxInt64
	}

	return
}

func wrappedTSDBIngestErr(ingestErr error, timestamp model.Time, labels []cortexpb.LabelAdapter) error {
	if ingestErr == nil {