sql: initialize sql instance during instance provider start

Before this change, there was a race condition where the instance
provider and the instance reader would start before the instance
provider created a SQL instance, potentially causing the reader to not
cache the instance before initialization was complete. This is
a problem in multi-tenant environments, where we may not be able to plan
queries if the reader does not know of any SQL instances.

This change moves sql instance initialization into the instance
provider's `Start()` function before starting the reader, so that the
instance is guaranteed to be visible to the reader on its first
rangefeed scan of the `system.sql_instances` table.

Fixes: cockroachdb#82706
Fixes: cockroachdb#81807
Fixes: cockroachdb#81567

Release note: None

pkg/ccl/streamingccl/streamingest/stream_ingestion_job_test.go

@@ -80,7 +80,6 @@ func verifyIngestionStats(t *testing.T, streamID int64, cutoverTime time.Time, s
 func TestTenantStreaming(t *testing.T) {
 	defer leaktest.AfterTest(t)()
 	defer log.Scope(t).Close(t)
-	skip.WithIssue(t, 82706)
 
 	skip.UnderRace(t, "slow under race")
 

pkg/server/server_sql.go

@@ -405,8 +405,12 @@ func newSQLServer(ctx context.Context, cfg sqlServerArgs) (*SQLServer, error) {
 		cfg.AmbientCtx,
 		cfg.stopper, cfg.clock, cfg.db, codec, cfg.Settings, sqllivenessKnobs,
 	)
+	// If the node id is already populated, we only need to create a placeholder
+	// instance provider without initializing the instance, since this is not a
+	// SQL pod server.
+	_, isNotSQLPod := cfg.nodeIDContainer.OptionalNodeID()
 	cfg.sqlInstanceProvider = instanceprovider.New(
-		cfg.stopper, cfg.db, codec, cfg.sqlLivenessProvider, cfg.advertiseAddr, cfg.rangeFeedFactory, cfg.clock,
+		cfg.stopper, cfg.db, codec, cfg.sqlLivenessProvider, cfg.advertiseAddr, cfg.rangeFeedFactory, cfg.clock, isNotSQLPod,
 	)
 
 	if !codec.ForSystemTenant() {
@@ -1156,7 +1160,7 @@ func (s *SQLServer) startSQLLivenessAndInstanceProviders(ctx context.Context) er
 	return nil
 }
 
-func (s *SQLServer) initInstanceID(ctx context.Context) error {
+func (s *SQLServer) setInstanceID(ctx context.Context) error {
 	if _, ok := s.sqlIDContainer.OptionalNodeID(); ok {
 		// sqlIDContainer has already been initialized with a node ID,
 		// we don't need to initialize a SQL instance ID in this case
@@ -1185,8 +1189,8 @@ func (s *SQLServer) preStart(
 	socketFile string,
 	orphanedLeasesTimeThresholdNanos int64,
 ) error {
-	// The sqlliveness and sqlinstance subsystem should be started first to ensure instance ID is
-	// initialized prior to any other systems that need it.
+	// The sqlliveness and sqlinstance subsystem should be started first to ensure
+	// the instance ID is initialized prior to any other systems that need it.
 	if err := s.startSQLLivenessAndInstanceProviders(ctx); err != nil {
 		return err
 	}
@@ -1197,7 +1201,7 @@ func (s *SQLServer) preStart(
 	if err := maybeCheckTenantExists(ctx, s.execCfg.Codec, s.execCfg.DB); err != nil {
 		return err
 	}
-	if err := s.initInstanceID(ctx); err != nil {
+	if err := s.setInstanceID(ctx); err != nil {
 		return err
 	}
 	s.connManager = connManager

pkg/sql/sqlinstance/instanceprovider/instanceprovider.go

@@ -47,6 +47,7 @@ type provider struct {
 	instanceID   base.SQLInstanceID
 	sessionID    sqlliveness.SessionID
 	initError    error
+	isSkeleton   bool
 	mu           struct {
 		syncutil.Mutex
 		started bool
@@ -62,6 +63,7 @@ func New(
 	addr string,
 	f *rangefeed.Factory,
 	clock *hlc.Clock,
+	isSkeleton bool,
 ) sqlinstance.Provider {
 	storage := instancestorage.NewStorage(db, codec, slProvider)
 	reader := instancestorage.NewReader(storage, slProvider.CachedReader(), f, codec, clock, stopper)
@@ -72,6 +74,7 @@ func New(
 		session:      slProvider,
 		instanceAddr: addr,
 		initialized:  make(chan struct{}),
+		isSkeleton:   isSkeleton,
 	}
 	return p
 }
@@ -81,6 +84,12 @@ func (p *provider) Start(ctx context.Context) error {
 	if p.started() {
 		return p.initError
 	}
+	// Initialize the instance. We need to do this before starting the reader, so
+	// that the reader sees the instance.
+	if err := p.initAndWait(ctx); err != nil {
+		return err
+	}
+
 	if err := p.Reader.Start(ctx); err != nil {
 		p.initOnce.Do(func() {
 			p.initError = err
@@ -106,21 +115,35 @@ func (p *provider) Instance(
 	if !p.started() {
 		return base.SQLInstanceID(0), "", sqlinstance.NotStartedError
 	}
-
-	p.maybeInitialize()
 	select {
 	case <-ctx.Done():
 		return base.SQLInstanceID(0), "", ctx.Err()
 	case <-p.stopper.ShouldQuiesce():
 		return base.SQLInstanceID(0), "", stop.ErrUnavailable
+	case <-p.initialized:
+		return p.instanceID, p.sessionID, p.initError
+	}
+}
+
+func (p *provider) initAndWait(ctx context.Context) error {
+	if p.isSkeleton {
+		// Don't initialize the instance if the provider is a placeholder.
+		return nil
+	}
+	p.maybeInitialize()
+	select {
+	case <-ctx.Done():
+		return ctx.Err()
+	case <-p.stopper.ShouldQuiesce():
+		return stop.ErrUnavailable
 	case <-p.initialized:
 		if p.initError == nil {
 			log.Ops.Infof(ctx, "created SQL instance %d", p.instanceID)
 		} else {
 			log.Ops.Warningf(ctx, "error creating SQL instance: %s", p.initError)
 		}
-		return p.instanceID, p.sessionID, p.initError
 	}
+	return p.initError
 }
 
 func (p *provider) maybeInitialize() {

pkg/sql/sqlinstance/instanceprovider/instanceprovider_test.go

@@ -65,6 +65,7 @@ func TestInstanceProvider(t *testing.T) {
 		defer stopper.Stop(ctx)
 		instanceProvider := instanceprovider.NewTestInstanceProvider(stopper, slInstance, addr)
 		slInstance.Start(ctx)
+		instanceProvider.InitAndWaitForTest(ctx)
 		instanceID, sessionID, err := instanceProvider.Instance(ctx)
 		require.NoError(t, err)
 		require.Equal(t, expectedInstanceID, instanceID)
@@ -101,6 +102,7 @@ func TestInstanceProvider(t *testing.T) {
 		instanceProvider := instanceprovider.NewTestInstanceProvider(stopper, slInstance, "addr")
 		slInstance.Start(ctx)
 		instanceProvider.ShutdownSQLInstanceForTest(ctx)
+		instanceProvider.InitAndWaitForTest(ctx)
 		_, _, err := instanceProvider.Instance(ctx)
 		require.Error(t, err)
 		require.Equal(t, "instance never initialized", err.Error())

pkg/sql/sqlinstance/instanceprovider/test_helpers.go

@@ -20,9 +20,10 @@ import (
 )
 
 // TestInstanceProvider exposes ShutdownSQLInstanceForTest
-// method for testing purposes.
+// and InitAndWaitForTest methods for testing purposes.
 type TestInstanceProvider interface {
 	sqlinstance.Provider
+	InitAndWaitForTest(context.Context)
 	ShutdownSQLInstanceForTest(context.Context)
 }
 
@@ -43,6 +44,14 @@ func NewTestInstanceProvider(
 	return p
 }
 
+// InitAndWaitForTest explicitly calls initAndWait for testing purposes.
+func (p *provider) InitAndWaitForTest(ctx context.Context) {
+	if err := p.initAndWait(ctx); err != nil {
+		//nolint:returnerrcheck
+		return
+	}
+}
+
 // ShutdownSQLInstanceForTest explicitly calls shutdownSQLInstance for testing purposes.
 func (p *provider) ShutdownSQLInstanceForTest(ctx context.Context) {
 	p.shutdownSQLInstance(ctx)

pkg/sql/sqlinstance/sqlinstance.go

@@ -47,8 +47,8 @@ type Provider interface {
 	// Instance returns the instance ID and sqlliveness.SessionID for the
 	// current SQL instance.
 	Instance(context.Context) (base.SQLInstanceID, sqlliveness.SessionID, error)
-	// Start starts the instanceprovider. This will block until
-	// the underlying instance data reader has been started.
+	// Start starts the instanceprovider and initializes the current SQL instance.
+	// This will block until the underlying instance data reader has been started.
 	Start(context.Context) error
 }