func (s *RegionRequestSender) sendKVReqToRegion(ctx *RPCContext, req *kvrpcpb.Request, timeout time.Duration) (resp *kvrpcpb.Response, retry bool, err error) {
req.Context = ctx.KVCtx
resp, err = s.client.SendKVReq(ctx.Addr, req, timeout)
if err != nil {
if e := s.onSendFail(ctx, err); e != nil {
return nil, false, errors.Trace(e)
}
return nil, true, nil
}
return
}
// sendKVReq sends req to tikv server. It will retry internally to find the right
// region leader if i) fails to establish a connection to server or ii) server
// returns `NotLeader`.
func (s *tikvStore) SendKVReq(bo *Backoffer, req *pb.Request, regionID RegionVerID) (*pb.Response, error) {
for {
region := s.regionCache.GetRegionByVerID(regionID)
if region == nil {
// If the region is not found in cache, it must be out
// of date and already be cleaned up. We can skip the
// RPC by returning RegionError directly.
return &pb.Response{
Type: req.GetType(),
RegionError: &errorpb.Error{StaleEpoch: &errorpb.StaleEpoch{}},
}, nil
}
req.Context = region.GetContext()
resp, err := s.client.SendKVReq(region.GetAddress(), req)
if err != nil {
s.regionCache.NextPeer(region.VerID())
err = bo.Backoff(boTiKVRPC, errors.Errorf("send tikv request error: %v, ctx: %s, try next peer later", err, req.Context))
if err != nil {
return nil, errors.Trace(err)
}
continue
}
if regionErr := resp.GetRegionError(); regionErr != nil {
// Retry if error is `NotLeader`.
if notLeader := regionErr.GetNotLeader(); notLeader != nil {
log.Warnf("tikv reports `NotLeader`: %s, ctx: %s, retry later", notLeader, req.Context)
s.regionCache.UpdateLeader(region.VerID(), notLeader.GetLeader().GetId())
if notLeader.GetLeader() == nil {
err = bo.Backoff(boRegionMiss, errors.Errorf("not leader: %v, ctx: %s", notLeader, req.Context))
if err != nil {
return nil, errors.Trace(err)
}
}
continue
}
// For other errors, we only drop cache here.
// Because caller may need to re-split the request.
log.Warnf("tikv reports region error: %s, ctx: %s", resp.GetRegionError(), req.Context)
s.regionCache.DropRegion(region.VerID())
return resp, nil
}
if resp.GetType() != req.GetType() {
return nil, errors.Trace(errMismatch(resp, req))
}
return resp, nil
}
}