release-21.1: cli/demo: assorted backports

pkg/cli/cli_test.go

@@ -417,7 +417,7 @@ func Example_demo() {
 
 	testData := [][]string{
 		{`demo`, `-e`, `show database`},
-		{`demo`, `-e`, `show database`, `--empty`},
+		{`demo`, `-e`, `show database`, `--no-example-database`},
 		{`demo`, `-e`, `show application_name`},
 		{`demo`, `--format=table`, `-e`, `show database`},
 		{`demo`, `-e`, `select 1 as "1"`, `-e`, `select 3 as "3"`},
@@ -448,7 +448,7 @@ func Example_demo() {
 	// demo -e show database
 	// database
 	// movr
-	// demo -e show database --empty
+	// demo -e show database --no-example-database
 	// database
 	// defaultdb
 	// demo -e show application_name

pkg/cli/cliflags/flags.go

@@ -1186,10 +1186,16 @@ If set, disable cockroach demo from attempting to obtain a temporary license.`,
 	}
 
 	UseEmptyDatabase = FlagInfo{
-		Name: "empty",
+		Name:        "empty",
+		Description: `Deprecated in favor of --no-example-database`,
+	}
+
+	NoExampleDatabase = FlagInfo{
+		Name:   "no-example-database",
+		EnvVar: "COCKROACH_NO_EXAMPLE_DATABASE",
 		Description: `
-Start with an empty database: avoid pre-loading a default dataset in
-the demo shell.`,
+Disable the creation of a default dataset in the demo shell.
+This makes 'cockroach demo' faster to start.`,
 	}
 
 	GeoLibsDir = FlagInfo{

pkg/cli/context.go

@@ -567,7 +567,7 @@ var demoCtx struct {
 	cacheSize                 int64
 	disableTelemetry          bool
 	disableLicenseAcquisition bool
-	useEmptyDatabase          bool
+	noExampleDatabase         bool
 	runWorkload               bool
 	localities                demoLocalityList
 	geoPartitionedReplicas    bool
@@ -585,7 +585,7 @@ func setDemoContextDefaults() {
 	demoCtx.nodes = 1
 	demoCtx.sqlPoolMemorySize = 128 << 20 // 128MB, chosen to fit 9 nodes on 2GB machine.
 	demoCtx.cacheSize = 64 << 20          // 64MB, chosen to fit 9 nodes on 2GB machine.
-	demoCtx.useEmptyDatabase = false
+	demoCtx.noExampleDatabase = false
 	demoCtx.simulateLatency = false
 	demoCtx.runWorkload = false
 	demoCtx.localities = nil

pkg/cli/demo.go

@@ -36,7 +36,7 @@ Start an in-memory, standalone, single-node CockroachDB instance, and open an
 interactive SQL prompt to it. Various datasets are available to be preloaded as
 subcommands: e.g. "cockroach demo startrek". See --help for a full list.
 
-By default, the 'movr' dataset is pre-loaded. You can also use --empty
+By default, the 'movr' dataset is pre-loaded. You can also use --no-example-database
 to avoid pre-loading a dataset.
 
 cockroach demo attempts to connect to a Cockroach Labs server to obtain a
@@ -105,14 +105,23 @@ func insertPair(pair regionPair, latency int) {
 	regionToLatency[pair.regionB] = latency
 }
 
+// Round-trip latencies collected from http://cloudping.co on 2019-09-11.
+var regionRoundTripLatencies = map[regionPair]int{
+	{regionA: "us-east1", regionB: "us-west1"}:     66,
+	{regionA: "us-east1", regionB: "europe-west1"}: 64,
+	{regionA: "us-west1", regionB: "europe-west1"}: 146,
+}
+
+var regionOneWayLatencies = make(map[regionPair]int)
+
 func init() {
+	// We record one-way latencies next, because the logic in our delayingConn
+	// and delayingListener is in terms of one-way network delays.
+	for pair, latency := range regionRoundTripLatencies {
+		regionOneWayLatencies[pair] = latency / 2
+	}
 	regionToRegionToLatency = make(map[string]map[string]int)
-	// Latencies collected from http://cloudping.co on 2019-09-11.
-	for pair, latency := range map[regionPair]int{
-		{regionA: "us-east1", regionB: "us-west1"}:     66,
-		{regionA: "us-east1", regionB: "europe-west1"}: 64,
-		{regionA: "us-west1", regionB: "europe-west1"}: 146,
-	} {
+	for pair, latency := range regionOneWayLatencies {
 		insertPair(pair, latency)
 		insertPair(regionPair{
 			regionA: pair.regionB,
@@ -175,14 +184,14 @@ func incrementTelemetryCounters(cmd *cobra.Command) {
 func checkDemoConfiguration(
 	cmd *cobra.Command, gen workload.Generator,
 ) (workload.Generator, error) {
-	if gen == nil && !demoCtx.useEmptyDatabase {
-		// Use a default dataset unless prevented by --empty.
+	if gen == nil && !demoCtx.noExampleDatabase {
+		// Use a default dataset unless prevented by --no-example-database.
 		gen = defaultGenerator
 	}
 
 	// Make sure that the user didn't request a workload and an empty database.
-	if demoCtx.runWorkload && demoCtx.useEmptyDatabase {
-		return nil, errors.New("cannot run a workload against an empty database")
+	if demoCtx.runWorkload && demoCtx.noExampleDatabase {
+		return nil, errors.New("cannot run a workload when generation of the example database is disabled")
 	}
 
 	// Make sure the number of nodes is valid.
@@ -208,9 +217,9 @@ func checkDemoConfiguration(
 			return nil, errors.Newf("enterprise features are needed for this demo (%s)", geoFlag)
 		}
 
-		// Make sure that the user didn't request to have a topology and an empty database.
-		if demoCtx.useEmptyDatabase {
-			return nil, errors.New("cannot setup geo-partitioned replicas topology on an empty database")
+		// Make sure that the user didn't request to have a topology and disable the example database.
+		if demoCtx.noExampleDatabase {
+			return nil, errors.New("cannot setup geo-partitioned replicas topology without generating an example database")
 		}
 
 		// Make sure that the Movr database is selected when automatically partitioning.
@@ -284,12 +293,19 @@ func runDemo(cmd *cobra.Command, gen workload.Generator) (err error) {
 	checkInteractive(cmdIn)
 
 	if cliCtx.isInteractive {
-		fmt.Printf(`#
+		printfUnlessEmbedded(`#
 # Welcome to the CockroachDB demo database!
 #
 # You are connected to a temporary, in-memory CockroachDB cluster of %d node%s.
 `, demoCtx.nodes, util.Pluralize(int64(demoCtx.nodes)))
 
+		if demoCtx.simulateLatency {
+			printfUnlessEmbedded(
+				"#\n# WARNING: the use of --%s is experimental. Some features may not work as expected.\n",
+				cliflags.Global.Name,
+			)
+		}
+
 		// Only print details about the telemetry configuration if the
 		// user has control over it.
 		if demoCtx.disableTelemetry {