Merge pull request #17808 from siyuanfoundation/3.5-downgrade-test

[3.5] add experimental-snapshot-catchup-entries flag

server/embed/config.go

@@ -151,7 +151,7 @@ type Config struct {
 	// follower to catch up.
 	// WARNING: only change this for tests.
 	// Always use "DefaultSnapshotCatchUpEntries"
-	SnapshotCatchUpEntries uint64
+	SnapshotCatchUpEntries uint64 `json:"experimental-snapshot-catch-up-entries"`
 
 	MaxSnapFiles uint `json:"max-snapshots"`
 	MaxWalFiles  uint `json:"max-wals"`

server/etcdmain/config.go

@@ -302,6 +302,7 @@ func newConfig() *config {
 	fs.BoolVar(&cfg.ec.ExperimentalMemoryMlock, "experimental-memory-mlock", cfg.ec.ExperimentalMemoryMlock, "Enable to enforce etcd pages (in particular bbolt) to stay in RAM.")
 	fs.BoolVar(&cfg.ec.ExperimentalTxnModeWriteWithSharedBuffer, "experimental-txn-mode-write-with-shared-buffer", true, "Enable the write transaction to use a shared buffer in its readonly check operations.")
 	fs.UintVar(&cfg.ec.ExperimentalBootstrapDefragThresholdMegabytes, "experimental-bootstrap-defrag-threshold-megabytes", 0, "Enable the defrag during etcd server bootstrap on condition that it will free at least the provided threshold of disk space. Needs to be set to non-zero value to take effect.")
+	fs.Uint64Var(&cfg.ec.SnapshotCatchUpEntries, "experimental-snapshot-catchup-entries", cfg.ec.SnapshotCatchUpEntries, "(WARNING: Use this flag with caution!) Number of entries for a slow follower to catch up after compacting the raft storage entries.")
 
 	// unsafe
 	fs.BoolVar(&cfg.ec.UnsafeNoFsync, "unsafe-no-fsync", false, "Disables fsync, unsafe, will cause data loss.")

server/etcdmain/config_test.go

@@ -505,7 +505,10 @@ func TestFlagsPresentInHelp(t *testing.T) {
 			// Ignored flags do not need to be in the help
 			return
 		}
-
+		if f.Name == "experimental-snapshot-catchup-entries" {
+			// Ignore because it is supposed to only be used in tests.
+			return
+		}
 		flagText := fmt.Sprintf("--%s", f.Name)
 		if !strings.Contains(flagsline, flagText) && !strings.Contains(usageline, flagText) {
 			t.Errorf("Neither flagsline nor usageline in help.go contains flag named %s", flagText)

tests/e2e/etcd_mix_versions_test.go

@@ -82,6 +82,7 @@ func mixVersionsSnapshotTestByAddingMember(t *testing.T, cfg e2e.EtcdProcessClus
 
 	t.Logf("Create an etcd cluster with %d member\n", cfg.ClusterSize)
 	cfg.SnapshotCount = 10
+	cfg.SnapshotCatchUpEntries = 10
 	cfg.BasePeerScheme = "unix" // to avoid port conflict
 
 	epc, err := e2e.NewEtcdProcessCluster(t, &cfg)
@@ -126,6 +127,7 @@ func mixVersionsSnapshotTestByMockPartition(t *testing.T, cfg e2e.EtcdProcessClu
 
 	t.Logf("Create an etcd cluster with %d member\n", cfg.ClusterSize)
 	cfg.SnapshotCount = 10
+	cfg.SnapshotCatchUpEntries = 10
 	cfg.BasePeerScheme = "unix" // to avoid port conflict
 
 	epc, err := e2e.NewEtcdProcessCluster(t, &cfg)
@@ -154,6 +156,12 @@ func mixVersionsSnapshotTestByMockPartition(t *testing.T, cfg e2e.EtcdProcessClu
 	require.NoError(t, err)
 
 	assertKVHash(t, epc)
+
+	leaderEPC = epc.Procs[epc.WaitLeader(t)]
+	if leaderEPC.Config().ExecPath == e2e.BinPath {
+		t.Log("Verify logs to check snapshot be sent from leader to follower")
+		e2e.AssertProcessLogs(t, leaderEPC, "sent database snapshot")
+	}
 }
 
 func writeKVs(t *testing.T, etcdctl *e2e.Etcdctl, startIdx, endIdx int) {

tests/framework/e2e/cluster.go

@@ -158,7 +158,8 @@ type EtcdProcessClusterConfig struct {
 
 	MetricsURLScheme string
 
-	SnapshotCount int // default is 10000
+	SnapshotCount          int // default is 10000
+	SnapshotCatchUpEntries int // default is 5000
 
 	ClientTLS             ClientConnType
 	ClientCertAuthEnabled bool
@@ -402,6 +403,12 @@ func (cfg *EtcdProcessClusterConfig) EtcdServerProcessConfig(tb testing.TB, i in
 		panic(fmt.Sprintf("Unknown cluster version %v", cfg.Version))
 	}
 
+	// the "--experimental-snapshot-catchup-entries" flag is not available in 3.4.
+	// so it should not be set if the process execPath is not BinPath.
+	if cfg.SnapshotCatchUpEntries > 0 && execPath == BinPath {
+		args = append(args, "--experimental-snapshot-catchup-entries", fmt.Sprintf("%d", cfg.SnapshotCatchUpEntries))
+	}
+
 	return &EtcdServerProcessConfig{
 		lg:                  cfg.Logger,
 		ExecPath:            execPath,