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Periodically update Cluster node latency

This commit is contained in:
Vladimir Mihailenco 2020-09-11 12:24:09 +03:00
parent 513fcfb224
commit 83d698027f
1 changed files with 14 additions and 9 deletions
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23
cluster.go
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@ -188,16 +188,19 @@ func (n *clusterNode) Close() error {
}
func (n *clusterNode) updateLatency() {
const probes = 10
const numProbe = 10
var dur uint64
var latency uint32
for i := 0; i < probes; i++ {
for i := 0; i < numProbe; i++ {
start := time.Now()
n.Client.Ping(context.TODO())
probe := uint32(time.Since(start) / time.Microsecond)
latency = (latency + probe) / 2
dur += uint64(time.Since(start) / time.Microsecond)
time.Sleep(time.Duration(10+rand.Intn(10)) * time.Millisecond)
}
atomic.StoreUint32(&n.latency, latency)
latency := float64(dur) / float64(numProbe)
atomic.StoreUint32(&n.latency, uint32(latency+0.5))
}
func (n *clusterNode) Latency() time.Duration {
@ -318,6 +321,9 @@ func (c *clusterNodes) GC(generation uint32) {
for addr, node := range c.nodes {
if node.Generation() >= generation {
c.activeAddrs = append(c.activeAddrs, addr)
if c.opt.RouteByLatency {
go node.updateLatency()
}
continue
}
@ -548,8 +554,6 @@ func (c *clusterState) slotSlaveNode(slot int) (*clusterNode, error) {
}
func (c *clusterState) slotClosestNode(slot int) (*clusterNode, error) {
const threshold = time.Millisecond
nodes := c.slotNodes(slot)
if len(nodes) == 0 {
return c.nodes.Random()
@ -560,13 +564,14 @@ func (c *clusterState) slotClosestNode(slot int) (*clusterNode, error) {
if n.Failing() {
continue
}
if node == nil || node.Latency()-n.Latency() > threshold {
if node == nil || n.Latency() < node.Latency() {
node = n
}
}
if node != nil {
return node, nil
}
// If all nodes are failing - return random node
return c.nodes.Random()
}