Ejemplo n.º 1
0
// getTablets gets all available tablets from HealthCheck,
// and selects the usable ones based several rules:
// master - return one from any cells with latest reparent timestamp;
// replica - return all from local cell.
func (dg *discoveryGateway) getTablets(keyspace, shard string, tabletType topodatapb.TabletType) []*discovery.TabletStats {
	tsList := dg.hc.GetTabletStatsFromTarget(keyspace, shard, tabletType)
	// for master, use any cells and return the one with max reparent timestamp.
	if tabletType == topodatapb.TabletType_MASTER {
		var maxTimestamp int64
		var t *discovery.TabletStats
		for _, ts := range tsList {
			if ts.LastError != nil || !ts.Serving {
				continue
			}
			if ts.TabletExternallyReparentedTimestamp >= maxTimestamp {
				maxTimestamp = ts.TabletExternallyReparentedTimestamp
				t = ts
			}
		}
		if t == nil {
			return nil
		}
		return []*discovery.TabletStats{t}
	}
	// for non-master, use only tablets from local cell and filter by replication lag.
	list := make([]*discovery.TabletStats, 0, len(tsList))
	for _, ts := range tsList {
		if ts.LastError != nil || !ts.Serving {
			continue
		}
		if dg.localCell != ts.Tablet.Alias.Cell {
			continue
		}
		list = append(list, ts)
	}
	list = discovery.FilterByReplicationLag(list)
	return list
}
Ejemplo n.º 2
0
// getEndPoints gets all available endpoints from HealthCheck,
// and selects the usable ones based several rules:
// master - return one from any cells with latest reparent timestamp;
// replica - return all from local cell.
// TODO(liang): select replica by replication lag.
func (dg *discoveryGateway) getEndPoints(keyspace, shard string, tabletType pbt.TabletType) []*pbt.EndPoint {
	epsList := dg.hc.GetEndPointStatsFromTarget(keyspace, shard, tabletType)
	// for master, use any cells and return the one with max reparent timestamp.
	if tabletType == pbt.TabletType_MASTER {
		var maxTimestamp int64
		var ep *pbt.EndPoint
		for _, eps := range epsList {
			if eps.LastError != nil || !eps.Serving {
				continue
			}
			if eps.TabletExternallyReparentedTimestamp >= maxTimestamp {
				maxTimestamp = eps.TabletExternallyReparentedTimestamp
				ep = eps.EndPoint
			}
		}
		if ep == nil {
			return nil
		}
		return []*pbt.EndPoint{ep}
	}
	// for non-master, use only endpoints from local cell and filter by replication lag.
	list := make([]*discovery.EndPointStats, 0, len(epsList))
	for _, eps := range epsList {
		if eps.LastError != nil || !eps.Serving {
			continue
		}
		if dg.localCell != eps.Cell {
			continue
		}
		list = append(list, eps)
	}
	list = discovery.FilterByReplicationLag(list)
	epList := make([]*pbt.EndPoint, 0, len(list))
	for _, eps := range list {
		epList = append(epList, eps.EndPoint)
	}
	return epList
}