Initial Store & Forward Implementation (#2917)

This adds store & forward relays into dendrite for p2p.
A few things have changed:
- new relay api serves new http endpoints for s&f federation
- updated outbound federation queueing which will attempt to forward
using s&f if appropriate
- database entries to track s&f relays for other nodes

federationapi/queue/queue_test.go

@@ -18,7 +18,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"sync"
 	"testing"
 	"time"
 
@@ -26,13 +25,11 @@ import (
 	"gotest.tools/v3/poll"
 
 	"github.com/matrix-org/gomatrixserverlib"
-	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 
 	"github.com/matrix-org/dendrite/federationapi/api"
 	"github.com/matrix-org/dendrite/federationapi/statistics"
 	"github.com/matrix-org/dendrite/federationapi/storage"
-	"github.com/matrix-org/dendrite/federationapi/storage/shared"
 	rsapi "github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/setup/config"
 	"github.com/matrix-org/dendrite/setup/process"
@@ -57,7 +54,7 @@ func mustCreateFederationDatabase(t *testing.T, dbType test.DBType, realDatabase
 		}
 	} else {
 		// Fake Database
-		db := createDatabase()
+		db := test.NewInMemoryFederationDatabase()
 		b := struct {
 			ProcessContext *process.ProcessContext
 		}{ProcessContext: process.NewProcessContext()}
@@ -65,220 +62,6 @@ func mustCreateFederationDatabase(t *testing.T, dbType test.DBType, realDatabase
 	}
 }
 
-func createDatabase() storage.Database {
-	return &fakeDatabase{
-		pendingPDUServers:  make(map[gomatrixserverlib.ServerName]struct{}),
-		pendingEDUServers:  make(map[gomatrixserverlib.ServerName]struct{}),
-		blacklistedServers: make(map[gomatrixserverlib.ServerName]struct{}),
-		pendingPDUs:        make(map[*shared.Receipt]*gomatrixserverlib.HeaderedEvent),
-		pendingEDUs:        make(map[*shared.Receipt]*gomatrixserverlib.EDU),
-		associatedPDUs:     make(map[gomatrixserverlib.ServerName]map[*shared.Receipt]struct{}),
-		associatedEDUs:     make(map[gomatrixserverlib.ServerName]map[*shared.Receipt]struct{}),
-	}
-}
-
-type fakeDatabase struct {
-	storage.Database
-	dbMutex            sync.Mutex
-	pendingPDUServers  map[gomatrixserverlib.ServerName]struct{}
-	pendingEDUServers  map[gomatrixserverlib.ServerName]struct{}
-	blacklistedServers map[gomatrixserverlib.ServerName]struct{}
-	pendingPDUs        map[*shared.Receipt]*gomatrixserverlib.HeaderedEvent
-	pendingEDUs        map[*shared.Receipt]*gomatrixserverlib.EDU
-	associatedPDUs     map[gomatrixserverlib.ServerName]map[*shared.Receipt]struct{}
-	associatedEDUs     map[gomatrixserverlib.ServerName]map[*shared.Receipt]struct{}
-}
-
-var nidMutex sync.Mutex
-var nid = int64(0)
-
-func (d *fakeDatabase) StoreJSON(ctx context.Context, js string) (*shared.Receipt, error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	var event gomatrixserverlib.HeaderedEvent
-	if err := json.Unmarshal([]byte(js), &event); err == nil {
-		nidMutex.Lock()
-		defer nidMutex.Unlock()
-		nid++
-		receipt := shared.NewReceipt(nid)
-		d.pendingPDUs[&receipt] = &event
-		return &receipt, nil
-	}
-
-	var edu gomatrixserverlib.EDU
-	if err := json.Unmarshal([]byte(js), &edu); err == nil {
-		nidMutex.Lock()
-		defer nidMutex.Unlock()
-		nid++
-		receipt := shared.NewReceipt(nid)
-		d.pendingEDUs[&receipt] = &edu
-		return &receipt, nil
-	}
-
-	return nil, errors.New("Failed to determine type of json to store")
-}
-
-func (d *fakeDatabase) GetPendingPDUs(ctx context.Context, serverName gomatrixserverlib.ServerName, limit int) (pdus map[*shared.Receipt]*gomatrixserverlib.HeaderedEvent, err error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	pduCount := 0
-	pdus = make(map[*shared.Receipt]*gomatrixserverlib.HeaderedEvent)
-	if receipts, ok := d.associatedPDUs[serverName]; ok {
-		for receipt := range receipts {
-			if event, ok := d.pendingPDUs[receipt]; ok {
-				pdus[receipt] = event
-				pduCount++
-				if pduCount == limit {
-					break
-				}
-			}
-		}
-	}
-	return pdus, nil
-}
-
-func (d *fakeDatabase) GetPendingEDUs(ctx context.Context, serverName gomatrixserverlib.ServerName, limit int) (edus map[*shared.Receipt]*gomatrixserverlib.EDU, err error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	eduCount := 0
-	edus = make(map[*shared.Receipt]*gomatrixserverlib.EDU)
-	if receipts, ok := d.associatedEDUs[serverName]; ok {
-		for receipt := range receipts {
-			if event, ok := d.pendingEDUs[receipt]; ok {
-				edus[receipt] = event
-				eduCount++
-				if eduCount == limit {
-					break
-				}
-			}
-		}
-	}
-	return edus, nil
-}
-
-func (d *fakeDatabase) AssociatePDUWithDestinations(ctx context.Context, destinations map[gomatrixserverlib.ServerName]struct{}, receipt *shared.Receipt) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	if _, ok := d.pendingPDUs[receipt]; ok {
-		for destination := range destinations {
-			if _, ok := d.associatedPDUs[destination]; !ok {
-				d.associatedPDUs[destination] = make(map[*shared.Receipt]struct{})
-			}
-			d.associatedPDUs[destination][receipt] = struct{}{}
-		}
-
-		return nil
-	} else {
-		return errors.New("PDU doesn't exist")
-	}
-}
-
-func (d *fakeDatabase) AssociateEDUWithDestinations(ctx context.Context, destinations map[gomatrixserverlib.ServerName]struct{}, receipt *shared.Receipt, eduType string, expireEDUTypes map[string]time.Duration) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	if _, ok := d.pendingEDUs[receipt]; ok {
-		for destination := range destinations {
-			if _, ok := d.associatedEDUs[destination]; !ok {
-				d.associatedEDUs[destination] = make(map[*shared.Receipt]struct{})
-			}
-			d.associatedEDUs[destination][receipt] = struct{}{}
-		}
-
-		return nil
-	} else {
-		return errors.New("EDU doesn't exist")
-	}
-}
-
-func (d *fakeDatabase) CleanPDUs(ctx context.Context, serverName gomatrixserverlib.ServerName, receipts []*shared.Receipt) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	if pdus, ok := d.associatedPDUs[serverName]; ok {
-		for _, receipt := range receipts {
-			delete(pdus, receipt)
-		}
-	}
-
-	return nil
-}
-
-func (d *fakeDatabase) CleanEDUs(ctx context.Context, serverName gomatrixserverlib.ServerName, receipts []*shared.Receipt) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	if edus, ok := d.associatedEDUs[serverName]; ok {
-		for _, receipt := range receipts {
-			delete(edus, receipt)
-		}
-	}
-
-	return nil
-}
-
-func (d *fakeDatabase) GetPendingPDUServerNames(ctx context.Context) ([]gomatrixserverlib.ServerName, error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	servers := []gomatrixserverlib.ServerName{}
-	for server := range d.pendingPDUServers {
-		servers = append(servers, server)
-	}
-	return servers, nil
-}
-
-func (d *fakeDatabase) GetPendingEDUServerNames(ctx context.Context) ([]gomatrixserverlib.ServerName, error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	servers := []gomatrixserverlib.ServerName{}
-	for server := range d.pendingEDUServers {
-		servers = append(servers, server)
-	}
-	return servers, nil
-}
-
-func (d *fakeDatabase) AddServerToBlacklist(serverName gomatrixserverlib.ServerName) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	d.blacklistedServers[serverName] = struct{}{}
-	return nil
-}
-
-func (d *fakeDatabase) RemoveServerFromBlacklist(serverName gomatrixserverlib.ServerName) error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	delete(d.blacklistedServers, serverName)
-	return nil
-}
-
-func (d *fakeDatabase) RemoveAllServersFromBlacklist() error {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	d.blacklistedServers = make(map[gomatrixserverlib.ServerName]struct{})
-	return nil
-}
-
-func (d *fakeDatabase) IsServerBlacklisted(serverName gomatrixserverlib.ServerName) (bool, error) {
-	d.dbMutex.Lock()
-	defer d.dbMutex.Unlock()
-
-	isBlacklisted := false
-	if _, ok := d.blacklistedServers[serverName]; ok {
-		isBlacklisted = true
-	}
-
-	return isBlacklisted, nil
-}
-
 type stubFederationRoomServerAPI struct {
 	rsapi.FederationRoomserverAPI
 }
@@ -290,8 +73,10 @@ func (r *stubFederationRoomServerAPI) QueryServerBannedFromRoom(ctx context.Cont
 
 type stubFederationClient struct {
 	api.FederationClient
-	shouldTxSucceed bool
-	txCount         atomic.Uint32
+	shouldTxSucceed      bool
+	shouldTxRelaySucceed bool
+	txCount              atomic.Uint32
+	txRelayCount         atomic.Uint32
 }
 
 func (f *stubFederationClient) SendTransaction(ctx context.Context, t gomatrixserverlib.Transaction) (res gomatrixserverlib.RespSend, err error) {
@@ -304,6 +89,16 @@ func (f *stubFederationClient) SendTransaction(ctx context.Context, t gomatrixse
 	return gomatrixserverlib.RespSend{}, result
 }
 
+func (f *stubFederationClient) P2PSendTransactionToRelay(ctx context.Context, u gomatrixserverlib.UserID, t gomatrixserverlib.Transaction, forwardingServer gomatrixserverlib.ServerName) (res gomatrixserverlib.EmptyResp, err error) {
+	var result error
+	if !f.shouldTxRelaySucceed {
+		result = fmt.Errorf("relay transaction failed")
+	}
+
+	f.txRelayCount.Add(1)
+	return gomatrixserverlib.EmptyResp{}, result
+}
+
 func mustCreatePDU(t *testing.T) *gomatrixserverlib.HeaderedEvent {
 	t.Helper()
 	content := `{"type":"m.room.message"}`
@@ -319,15 +114,18 @@ func mustCreateEDU(t *testing.T) *gomatrixserverlib.EDU {
 	return &gomatrixserverlib.EDU{Type: gomatrixserverlib.MTyping}
 }
 
-func testSetup(failuresUntilBlacklist uint32, shouldTxSucceed bool, t *testing.T, dbType test.DBType, realDatabase bool) (storage.Database, *stubFederationClient, *OutgoingQueues, *process.ProcessContext, func()) {
+func testSetup(failuresUntilBlacklist uint32, failuresUntilAssumedOffline uint32, shouldTxSucceed bool, shouldTxRelaySucceed bool, t *testing.T, dbType test.DBType, realDatabase bool) (storage.Database, *stubFederationClient, *OutgoingQueues, *process.ProcessContext, func()) {
 	db, processContext, close := mustCreateFederationDatabase(t, dbType, realDatabase)
 
 	fc := &stubFederationClient{
-		shouldTxSucceed: shouldTxSucceed,
-		txCount:         *atomic.NewUint32(0),
+		shouldTxSucceed:      shouldTxSucceed,
+		shouldTxRelaySucceed: shouldTxRelaySucceed,
+		txCount:              *atomic.NewUint32(0),
+		txRelayCount:         *atomic.NewUint32(0),
 	}
 	rs := &stubFederationRoomServerAPI{}
-	stats := statistics.NewStatistics(db, failuresUntilBlacklist)
+
+	stats := statistics.NewStatistics(db, failuresUntilBlacklist, failuresUntilAssumedOffline)
 	signingInfo := []*gomatrixserverlib.SigningIdentity{
 		{
 			KeyID:      "ed21019:auto",
@@ -344,7 +142,7 @@ func TestSendPDUOnSuccessRemovedFromDB(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -373,7 +171,7 @@ func TestSendEDUOnSuccessRemovedFromDB(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -402,7 +200,7 @@ func TestSendPDUOnFailStoredInDB(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -432,7 +230,7 @@ func TestSendEDUOnFailStoredInDB(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -462,7 +260,7 @@ func TestSendPDUAgainDoesntInterruptBackoff(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -513,7 +311,7 @@ func TestSendEDUAgainDoesntInterruptBackoff(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -564,7 +362,7 @@ func TestSendPDUMultipleFailuresBlacklisted(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(2)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -596,7 +394,7 @@ func TestSendEDUMultipleFailuresBlacklisted(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(2)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -628,7 +426,7 @@ func TestSendPDUBlacklistedWithPriorExternalFailure(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(2)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -662,7 +460,7 @@ func TestSendEDUBlacklistedWithPriorExternalFailure(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(2)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -696,7 +494,7 @@ func TestRetryServerSendsPDUSuccessfully(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(1)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -730,8 +528,8 @@ func TestRetryServerSendsPDUSuccessfully(t *testing.T) {
 	poll.WaitOn(t, checkBlacklisted, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
 
 	fc.shouldTxSucceed = true
-	db.RemoveServerFromBlacklist(destination)
-	queues.RetryServer(destination)
+	wasBlacklisted := dest.statistics.MarkServerAlive()
+	queues.RetryServer(destination, wasBlacklisted)
 	checkRetry := func(log poll.LogT) poll.Result {
 		data, dbErr := db.GetPendingPDUs(pc.Context(), destination, 100)
 		assert.NoError(t, dbErr)
@@ -747,7 +545,7 @@ func TestRetryServerSendsEDUSuccessfully(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(1)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -781,8 +579,8 @@ func TestRetryServerSendsEDUSuccessfully(t *testing.T) {
 	poll.WaitOn(t, checkBlacklisted, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
 
 	fc.shouldTxSucceed = true
-	db.RemoveServerFromBlacklist(destination)
-	queues.RetryServer(destination)
+	wasBlacklisted := dest.statistics.MarkServerAlive()
+	queues.RetryServer(destination, wasBlacklisted)
 	checkRetry := func(log poll.LogT) poll.Result {
 		data, dbErr := db.GetPendingEDUs(pc.Context(), destination, 100)
 		assert.NoError(t, dbErr)
@@ -801,7 +599,7 @@ func TestSendPDUBatches(t *testing.T) {
 
 	// test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
 	// db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, dbType, true)
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -845,7 +643,7 @@ func TestSendEDUBatches(t *testing.T) {
 
 	// test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
 	// db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, dbType, true)
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -889,7 +687,7 @@ func TestSendPDUAndEDUBatches(t *testing.T) {
 
 	// test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
 	// db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, dbType, true)
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -940,7 +738,7 @@ func TestExternalFailureBackoffDoesntStartQueue(t *testing.T) {
 	t.Parallel()
 	failuresUntilBlacklist := uint32(16)
 	destination := gomatrixserverlib.ServerName("remotehost")
-	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, true, t, test.DBTypeSQLite, false)
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, true, false, t, test.DBTypeSQLite, false)
 	defer close()
 	defer func() {
 		pc.ShutdownDendrite()
@@ -978,7 +776,7 @@ func TestQueueInteractsWithRealDatabasePDUAndEDU(t *testing.T) {
 	destination := gomatrixserverlib.ServerName("remotehost")
 	destinations := map[gomatrixserverlib.ServerName]struct{}{destination: {}}
 	test.WithAllDatabases(t, func(t *testing.T, dbType test.DBType) {
-		db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, false, t, dbType, true)
+		db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilBlacklist+1, false, false, t, dbType, true)
 		// NOTE : These defers aren't called if go test is killed so the dbs may not get cleaned up.
 		defer close()
 		defer func() {
@@ -1023,8 +821,8 @@ func TestQueueInteractsWithRealDatabasePDUAndEDU(t *testing.T) {
 		poll.WaitOn(t, checkBlacklisted, poll.WithTimeout(10*time.Second), poll.WithDelay(100*time.Millisecond))
 
 		fc.shouldTxSucceed = true
-		db.RemoveServerFromBlacklist(destination)
-		queues.RetryServer(destination)
+		wasBlacklisted := dest.statistics.MarkServerAlive()
+		queues.RetryServer(destination, wasBlacklisted)
 		checkRetry := func(log poll.LogT) poll.Result {
 			pduData, dbErrPDU := db.GetPendingPDUs(pc.Context(), destination, 200)
 			assert.NoError(t, dbErrPDU)
@@ -1038,3 +836,147 @@ func TestQueueInteractsWithRealDatabasePDUAndEDU(t *testing.T) {
 		poll.WaitOn(t, checkRetry, poll.WithTimeout(10*time.Second), poll.WithDelay(100*time.Millisecond))
 	})
 }
+
+func TestSendPDUMultipleFailuresAssumedOffline(t *testing.T) {
+	t.Parallel()
+	failuresUntilBlacklist := uint32(7)
+	failuresUntilAssumedOffline := uint32(2)
+	destination := gomatrixserverlib.ServerName("remotehost")
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilAssumedOffline, false, false, t, test.DBTypeSQLite, false)
+	defer close()
+	defer func() {
+		pc.ShutdownDendrite()
+		<-pc.WaitForShutdown()
+	}()
+
+	ev := mustCreatePDU(t)
+	err := queues.SendEvent(ev, "localhost", []gomatrixserverlib.ServerName{destination})
+	assert.NoError(t, err)
+
+	check := func(log poll.LogT) poll.Result {
+		if fc.txCount.Load() == failuresUntilAssumedOffline {
+			data, dbErr := db.GetPendingPDUs(pc.Context(), destination, 100)
+			assert.NoError(t, dbErr)
+			if len(data) == 1 {
+				if val, _ := db.IsServerAssumedOffline(context.Background(), destination); val {
+					return poll.Success()
+				}
+				return poll.Continue("waiting for server to be assumed offline")
+			}
+			return poll.Continue("waiting for event to be added to database. Currently present PDU: %d", len(data))
+		}
+		return poll.Continue("waiting for more send attempts before checking database. Currently %d", fc.txCount.Load())
+	}
+	poll.WaitOn(t, check, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
+}
+
+func TestSendEDUMultipleFailuresAssumedOffline(t *testing.T) {
+	t.Parallel()
+	failuresUntilBlacklist := uint32(7)
+	failuresUntilAssumedOffline := uint32(2)
+	destination := gomatrixserverlib.ServerName("remotehost")
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilAssumedOffline, false, false, t, test.DBTypeSQLite, false)
+	defer close()
+	defer func() {
+		pc.ShutdownDendrite()
+		<-pc.WaitForShutdown()
+	}()
+
+	ev := mustCreateEDU(t)
+	err := queues.SendEDU(ev, "localhost", []gomatrixserverlib.ServerName{destination})
+	assert.NoError(t, err)
+
+	check := func(log poll.LogT) poll.Result {
+		if fc.txCount.Load() == failuresUntilAssumedOffline {
+			data, dbErr := db.GetPendingEDUs(pc.Context(), destination, 100)
+			assert.NoError(t, dbErr)
+			if len(data) == 1 {
+				if val, _ := db.IsServerAssumedOffline(context.Background(), destination); val {
+					return poll.Success()
+				}
+				return poll.Continue("waiting for server to be assumed offline")
+			}
+			return poll.Continue("waiting for event to be added to database. Currently present EDU: %d", len(data))
+		}
+		return poll.Continue("waiting for more send attempts before checking database. Currently %d", fc.txCount.Load())
+	}
+	poll.WaitOn(t, check, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
+}
+
+func TestSendPDUOnRelaySuccessRemovedFromDB(t *testing.T) {
+	t.Parallel()
+	failuresUntilBlacklist := uint32(16)
+	failuresUntilAssumedOffline := uint32(1)
+	destination := gomatrixserverlib.ServerName("remotehost")
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilAssumedOffline, false, true, t, test.DBTypeSQLite, false)
+	defer close()
+	defer func() {
+		pc.ShutdownDendrite()
+		<-pc.WaitForShutdown()
+	}()
+
+	relayServers := []gomatrixserverlib.ServerName{"relayserver"}
+	queues.statistics.ForServer(destination).AddRelayServers(relayServers)
+
+	ev := mustCreatePDU(t)
+	err := queues.SendEvent(ev, "localhost", []gomatrixserverlib.ServerName{destination})
+	assert.NoError(t, err)
+
+	check := func(log poll.LogT) poll.Result {
+		if fc.txCount.Load() == 1 {
+			if fc.txRelayCount.Load() == 1 {
+				data, dbErr := db.GetPendingPDUs(pc.Context(), destination, 100)
+				assert.NoError(t, dbErr)
+				if len(data) == 0 {
+					return poll.Success()
+				}
+				return poll.Continue("waiting for event to be removed from database. Currently present PDU: %d", len(data))
+			}
+			return poll.Continue("waiting for more relay send attempts before checking database. Currently %d", fc.txRelayCount.Load())
+		}
+		return poll.Continue("waiting for more send attempts before checking database. Currently %d", fc.txCount.Load())
+	}
+	poll.WaitOn(t, check, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
+
+	assumedOffline, _ := db.IsServerAssumedOffline(context.Background(), destination)
+	assert.Equal(t, true, assumedOffline)
+}
+
+func TestSendEDUOnRelaySuccessRemovedFromDB(t *testing.T) {
+	t.Parallel()
+	failuresUntilBlacklist := uint32(16)
+	failuresUntilAssumedOffline := uint32(1)
+	destination := gomatrixserverlib.ServerName("remotehost")
+	db, fc, queues, pc, close := testSetup(failuresUntilBlacklist, failuresUntilAssumedOffline, false, true, t, test.DBTypeSQLite, false)
+	defer close()
+	defer func() {
+		pc.ShutdownDendrite()
+		<-pc.WaitForShutdown()
+	}()
+
+	relayServers := []gomatrixserverlib.ServerName{"relayserver"}
+	queues.statistics.ForServer(destination).AddRelayServers(relayServers)
+
+	ev := mustCreateEDU(t)
+	err := queues.SendEDU(ev, "localhost", []gomatrixserverlib.ServerName{destination})
+	assert.NoError(t, err)
+
+	check := func(log poll.LogT) poll.Result {
+		if fc.txCount.Load() == 1 {
+			if fc.txRelayCount.Load() == 1 {
+				data, dbErr := db.GetPendingEDUs(pc.Context(), destination, 100)
+				assert.NoError(t, dbErr)
+				if len(data) == 0 {
+					return poll.Success()
+				}
+				return poll.Continue("waiting for event to be removed from database. Currently present EDU: %d", len(data))
+			}
+			return poll.Continue("waiting for more relay send attempts before checking database. Currently %d", fc.txRelayCount.Load())
+		}
+		return poll.Continue("waiting for more send attempts before checking database. Currently %d", fc.txCount.Load())
+	}
+	poll.WaitOn(t, check, poll.WithTimeout(5*time.Second), poll.WithDelay(100*time.Millisecond))
+
+	assumedOffline, _ := db.IsServerAssumedOffline(context.Background(), destination)
+	assert.Equal(t, true, assumedOffline)
+}