Golang roachpb.NewReverseScan函数代码示例

// TestMultiRangeScanReverseScanInconsistent verifies that a Scan/ReverseScan
// across ranges that doesn't require read consistency will set a timestamp
// using the clock local to the distributed sender.
func TestMultiRangeScanReverseScanInconsistent(t *testing.T) {
	defer leaktest.AfterTest(t)
	s, db := setupMultipleRanges(t, "b")
	defer s.Stop()

	// Write keys "a" and "b", the latter of which is the first key in the
	// second range.
	keys := []string{"a", "b"}
	ts := []time.Time{}
	for i, key := range keys {
		b := &client.Batch{}
		b.Put(key, "value")
		if err := db.Run(b); err != nil {
			t.Fatal(err)
		}
		ts = append(ts, b.Results[0].Rows[0].Timestamp())
		log.Infof("%d: %s", i, b.Results[0].Rows[0].Timestamp())
	}

	// Do an inconsistent Scan/ReverseScan from a new DistSender and verify
	// it does the read at its local clock and doesn't receive an
	// OpRequiresTxnError. We set the local clock to the timestamp of
	// the first key to verify it's used to read only key "a".
	manual := hlc.NewManualClock(ts[1].UnixNano() - 1)
	clock := hlc.NewClock(manual.UnixNano)
	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: clock}, s.Gossip())

	// Scan.
	sa := roachpb.NewScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ScanRequest)
	reply, err := client.SendWrappedWith(ds, nil, roachpb.BatchRequest_Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, sa)
	if err != nil {
		t.Fatal(err)
	}
	sr := reply.(*roachpb.ScanResponse)

	if l := len(sr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(sr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}

	// ReverseScan.
	rsa := roachpb.NewReverseScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ReverseScanRequest)
	reply, err = client.SendWrappedWith(ds, nil, roachpb.BatchRequest_Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, rsa)
	if err != nil {
		t.Fatal(err)
	}
	rsr := reply.(*roachpb.ReverseScanResponse)
	if l := len(rsr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(rsr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}
}

func (b *Batch) scan(s, e interface{}, maxRows int64, isReverse bool) {
	begin, err := marshalKey(s)
	if err != nil {
		b.initResult(0, 0, err)
		return
	}
	end, err := marshalKey(e)
	if err != nil {
		b.initResult(0, 0, err)
		return
	}
	if !isReverse {
		b.reqs = append(b.reqs, roachpb.NewScan(roachpb.Key(begin), roachpb.Key(end), maxRows))
	} else {
		b.reqs = append(b.reqs, roachpb.NewReverseScan(roachpb.Key(begin), roachpb.Key(end), maxRows))
	}
	b.initResult(1, 0, nil)
}

func (b *Batch) scan(s, e interface{}, isReverse bool) {
	begin, err := marshalKey(s)
	if err != nil {
		b.initResult(0, 0, notRaw, err)
		return
	}
	end, err := marshalKey(e)
	if err != nil {
		b.initResult(0, 0, notRaw, err)
		return
	}
	if !isReverse {
		b.appendReqs(roachpb.NewScan(begin, end))
	} else {
		b.appendReqs(roachpb.NewReverseScan(begin, end))
	}
	b.initResult(1, 0, notRaw, nil)
}

// TestMultiRangeScanReverseScanInconsistent verifies that a Scan/ReverseScan
// across ranges that doesn't require read consistency will set a timestamp
// using the clock local to the distributed sender.
func TestMultiRangeScanReverseScanInconsistent(t *testing.T) {
	defer leaktest.AfterTest(t)

	s := server.StartTestServer(t)
	defer s.Stop()
	db := setupMultipleRanges(t, s, "b")

	// Write keys "a" and "b", the latter of which is the first key in the
	// second range.
	keys := [2]string{"a", "b"}
	ts := [2]time.Time{}
	for i, key := range keys {
		b := &client.Batch{}
		b.Put(key, "value")
		if pErr := db.Run(b); pErr != nil {
			t.Fatal(pErr)
		}
		ts[i] = b.Results[0].Rows[0].Timestamp()
		log.Infof("%d: %d.%d", i, ts[i].Unix(), ts[i].Nanosecond())
		if i == 0 {
			util.SucceedsWithin(t, time.Second, func() error {
				// Enforce that when we write the second key, it's written
				// with a strictly higher timestamp. We're dropping logical
				// ticks and the clock may just have been pushed into the
				// future, so that's necessary. See #3122.
				if !s.Clock().PhysicalTime().After(ts[0]) {
					return errors.New("time stands still")
				}
				return nil
			})
		}
	}

	// Do an inconsistent Scan/ReverseScan from a new DistSender and verify
	// it does the read at its local clock and doesn't receive an
	// OpRequiresTxnError. We set the local clock to the timestamp of
	// the first key to verify it's used to read only key "a".
	manual := hlc.NewManualClock(ts[1].UnixNano() - 1)
	clock := hlc.NewClock(manual.UnixNano)
	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: clock, RPCContext: s.RPCContext()}, s.Gossip())

	// Scan.
	sa := roachpb.NewScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ScanRequest)
	reply, pErr := client.SendWrappedWith(ds, nil, roachpb.Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, sa)
	if pErr != nil {
		t.Fatal(pErr)
	}
	sr := reply.(*roachpb.ScanResponse)

	if l := len(sr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(sr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}

	// ReverseScan.
	rsa := roachpb.NewReverseScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ReverseScanRequest)
	reply, pErr = client.SendWrappedWith(ds, nil, roachpb.Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, rsa)
	if pErr != nil {
		t.Fatal(pErr)
	}
	rsr := reply.(*roachpb.ReverseScanResponse)
	if l := len(rsr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(rsr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}
}

// TestMultiRangeScanReverseScanInconsistent verifies that a Scan/ReverseScan
// across ranges that doesn't require read consistency will set a timestamp
// using the clock local to the distributed sender.
func TestMultiRangeScanReverseScanInconsistent(t *testing.T) {
	defer leaktest.AfterTest(t)
	s, db := setupMultipleRanges(t, "b")
	defer s.Stop()

	// Write keys "a" and "b", the latter of which is the first key in the
	// second range.
	keys := [2]string{"a", "b"}
	ts := [2]time.Time{}
	// This outer loop may seem awkward, but we've actually had issue #3122
	// since the two timestamps ended up equal. This can happen (very rarely)
	// since both timestamps are HLC internally and then have their logical
	// component dropped. Lease changes can push the HLC ahead of the wall
	// time for short amounts of time, so that losing the logical tick matters.
	for !ts[1].After(ts[0]) {
		for i, key := range keys {
			b := &client.Batch{}
			b.Put(key, "value")
			if err := db.Run(b); err != nil {
				t.Fatal(err)
			}
			ts[i] = b.Results[0].Rows[0].Timestamp()
			log.Infof("%d: %s", i, b.Results[0].Rows[0].Timestamp())
		}
	}

	// Do an inconsistent Scan/ReverseScan from a new DistSender and verify
	// it does the read at its local clock and doesn't receive an
	// OpRequiresTxnError. We set the local clock to the timestamp of
	// the first key to verify it's used to read only key "a".
	manual := hlc.NewManualClock(ts[1].UnixNano() - 1)
	clock := hlc.NewClock(manual.UnixNano)
	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: clock}, s.Gossip())

	// Scan.
	sa := roachpb.NewScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ScanRequest)
	reply, err := client.SendWrappedWith(ds, nil, roachpb.Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, sa)
	if err != nil {
		t.Fatal(err)
	}
	sr := reply.(*roachpb.ScanResponse)

	if l := len(sr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(sr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}

	// ReverseScan.
	rsa := roachpb.NewReverseScan(roachpb.Key("a"), roachpb.Key("c"), 0).(*roachpb.ReverseScanRequest)
	reply, err = client.SendWrappedWith(ds, nil, roachpb.Header{
		ReadConsistency: roachpb.INCONSISTENT,
	}, rsa)
	if err != nil {
		t.Fatal(err)
	}
	rsr := reply.(*roachpb.ReverseScanResponse)
	if l := len(rsr.Rows); l != 1 {
		t.Fatalf("expected 1 row; got %d", l)
	}
	if key := string(rsr.Rows[0].Key); keys[0] != key {
		t.Errorf("expected key %q; got %q", keys[0], key)
	}
}

// TestMultiRangeScanReverseScanInconsistent verifies that a Scan/ReverseScan
// across ranges that doesn't require read consistency will set a timestamp
// using the clock local to the distributed sender.
func TestMultiRangeScanReverseScanInconsistent(t *testing.T) {
	defer leaktest.AfterTest(t)()

	s := server.StartTestServer(t)
	defer s.Stop()
	db := setupMultipleRanges(t, s, "b")

	// Write keys "a" and "b", the latter of which is the first key in the
	// second range.
	keys := [2]string{"a", "b"}
	ts := [2]roachpb.Timestamp{}
	for i, key := range keys {
		b := &client.Batch{}
		b.Put(key, "value")
		if err := db.Run(b); err != nil {
			t.Fatal(err)
		}
		ts[i] = s.Clock().Now()
		log.Infof("%d: %d", i, ts[i])
		if i == 0 {
			util.SucceedsSoon(t, func() error {
				// Enforce that when we write the second key, it's written
				// with a strictly higher timestamp. We're dropping logical
				// ticks and the clock may just have been pushed into the
				// future, so that's necessary. See #3122.
				if !ts[0].Less(s.Clock().Now()) {
					return errors.New("time stands still")
				}
				return nil
			})
		}
	}

	// Do an inconsistent Scan/ReverseScan from a new DistSender and verify
	// it does the read at its local clock and doesn't receive an
	// OpRequiresTxnError. We set the local clock to the timestamp of
	// just above the first key to verify it's used to read only key "a".
	for _, request := range []roachpb.Request{
		roachpb.NewScan(roachpb.Key("a"), roachpb.Key("c"), 0),
		roachpb.NewReverseScan(roachpb.Key("a"), roachpb.Key("c"), 0),
	} {
		manual := hlc.NewManualClock(ts[0].WallTime + 1)
		clock := hlc.NewClock(manual.UnixNano)
		ds := kv.NewDistSender(&kv.DistSenderContext{Clock: clock, RPCContext: s.RPCContext()}, s.Gossip())

		reply, err := client.SendWrappedWith(ds, nil, roachpb.Header{
			ReadConsistency: roachpb.INCONSISTENT,
		}, request)
		if err != nil {
			t.Fatal(err)
		}

		var rows []roachpb.KeyValue
		switch r := reply.(type) {
		case *roachpb.ScanResponse:
			rows = r.Rows
		case *roachpb.ReverseScanResponse:
			rows = r.Rows
		default:
			t.Fatalf("unexpected response %T: %v", reply, reply)
		}

		if l := len(rows); l != 1 {
			t.Fatalf("expected 1 row; got %d", l)
		}
		if key := string(rows[0].Key); keys[0] != key {
			t.Errorf("expected key %q; got %q", keys[0], key)
		}
	}
}