Change `EnableTSOFollowerProxy` may not take effect · Issue #8947 · tikv/pd

Bug Report

Lines 333 to 402 in c1ee9cf

    
           func (c *tsoClient) handleDispatcher( 
        
           	dispatcherCtx context.Context, 
        
           	dc string, 
        
           	tbc *tsoBatchController, 
        
           ) { 
        
           	var ( 
        
           		err       error 
        
           		streamURL string 
        
           		stream    tsoStream 
        
           		streamCtx context.Context 
        
           		cancel    context.CancelFunc 
        
           		// url -> connectionContext 
        
           		connectionCtxs sync.Map 
        
           	) 
        
           	defer func() { 
        
           		log.Info("[tso] exit tso dispatcher", zap.String("dc-location", dc)) 
        
           		// Cancel all connections. 
        
           		connectionCtxs.Range(func(_, cc any) bool { 
        
           			cc.(*tsoConnectionContext).cancel() 
        
           			return true 
        
           		}) 
        
           		// Clear the tso batch controller. 
        
           		tbc.clear() 
        
           		c.wg.Done() 
        
           	}() 
        
           	// Call updateTSOConnectionCtxs once to init the connectionCtxs first. 
        
           	c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs) 
        
           	// Only the Global TSO needs to watch the updateTSOConnectionCtxsCh to sense the 
        
           	// change of the cluster when TSO Follower Proxy is enabled. 
        
           	// TODO: support TSO Follower Proxy for the Local TSO. 
        
           	if dc == globalDCLocation { 
        
           		go func() { 
        
           			var updateTicker = &time.Ticker{} 
        
           			setNewUpdateTicker := func(ticker *time.Ticker) { 
        
           				if updateTicker.C != nil { 
        
           					updateTicker.Stop() 
        
           				} 
        
           				updateTicker = ticker 
        
           			} 
        
           			// Set to nil before returning to ensure that the existing ticker can be GC. 
        
           			defer setNewUpdateTicker(nil) 
        
           			for { 
        
           				select { 
        
           				case <-dispatcherCtx.Done(): 
        
           					return 
        
           				case <-c.option.enableTSOFollowerProxyCh: 
        
           					enableTSOFollowerProxy := c.option.getEnableTSOFollowerProxy() 
        
           					log.Info("[tso] tso follower proxy status changed", 
        
           						zap.String("dc-location", dc), 
        
           						zap.Bool("enable", enableTSOFollowerProxy)) 
        
           					if enableTSOFollowerProxy && updateTicker.C == nil { 
        
           						// Because the TSO Follower Proxy is enabled, 
        
           						// the periodic check needs to be performed. 
        
           						setNewUpdateTicker(time.NewTicker(memberUpdateInterval)) 
        
           					} else if !enableTSOFollowerProxy && updateTicker.C != nil { 
        
           						// Because the TSO Follower Proxy is disabled, 
        
           						// the periodic check needs to be turned off. 
        
           						setNewUpdateTicker(&time.Ticker{}) 
        
           					} else { 
        
           						// The status of TSO Follower Proxy does not change, and updateTSOConnectionCtxs is not triggered 
        
           						continue 
        
           					} 
        
           				case <-updateTicker.C: 
        
           				case <-c.updateTSOConnectionCtxsCh: 
        
           				} 
        
           				c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs) 
        
           			} 
        
           		}() 
        
           	}

If the option is true at line 359, it might connect to the follower. After that, the option is changed to false at line 380. This change may not take effect since the enableTSOFollowerProxy is false and updateTicker.C is nil.

It's better to initialize the ticker before stepping into the loop.

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Change `EnableTSOFollowerProxy` may not take effect #8947

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	func (c *tsoClient) handleDispatcher(
	dispatcherCtx context.Context,
	dc string,
	tbc *tsoBatchController,
	) {
	var (
	err error
	streamURL string
	stream tsoStream
	streamCtx context.Context
	cancel context.CancelFunc
	// url -> connectionContext
	connectionCtxs sync.Map
	)
	defer func() {
	log.Info("[tso] exit tso dispatcher", zap.String("dc-location", dc))
	// Cancel all connections.
	connectionCtxs.Range(func(_, cc any) bool {
	cc.(*tsoConnectionContext).cancel()
	return true
	})
	// Clear the tso batch controller.
	tbc.clear()
	c.wg.Done()
	}()
	// Call updateTSOConnectionCtxs once to init the connectionCtxs first.
	c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs)
	// Only the Global TSO needs to watch the updateTSOConnectionCtxsCh to sense the
	// change of the cluster when TSO Follower Proxy is enabled.
	// TODO: support TSO Follower Proxy for the Local TSO.
	if dc == globalDCLocation {
	go func() {
	var updateTicker = &time.Ticker{}
	setNewUpdateTicker := func(ticker *time.Ticker) {
	if updateTicker.C != nil {
	updateTicker.Stop()
	}
	updateTicker = ticker
	}
	// Set to nil before returning to ensure that the existing ticker can be GC.
	defer setNewUpdateTicker(nil)

	for {
	select {
	case <-dispatcherCtx.Done():
	return
	case <-c.option.enableTSOFollowerProxyCh:
	enableTSOFollowerProxy := c.option.getEnableTSOFollowerProxy()
	log.Info("[tso] tso follower proxy status changed",
	zap.String("dc-location", dc),
	zap.Bool("enable", enableTSOFollowerProxy))
	if enableTSOFollowerProxy && updateTicker.C == nil {
	// Because the TSO Follower Proxy is enabled,
	// the periodic check needs to be performed.
	setNewUpdateTicker(time.NewTicker(memberUpdateInterval))
	} else if !enableTSOFollowerProxy && updateTicker.C != nil {
	// Because the TSO Follower Proxy is disabled,
	// the periodic check needs to be turned off.
	setNewUpdateTicker(&time.Ticker{})
	} else {
	// The status of TSO Follower Proxy does not change, and updateTSOConnectionCtxs is not triggered
	continue
	}
	case <-updateTicker.C:
	case <-c.updateTSOConnectionCtxsCh:
	}
	c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs)
	}
	}()
	}

Change EnableTSOFollowerProxy may not take effect #8947

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Change `EnableTSOFollowerProxy` may not take effect #8947