enhance: [10kcp] Enable score based balance channel policy (#38301)

issue: #38142
current balance channel policy only consider current collection's
distribution, so if all collections has 1 channel, and all channels has
been loaded on same querynode, after querynode num increase, balance
channel won't be triggered.

This PR enable score based balance channel policy, to achieve:

1. distribute all channels evenly across multiple querynodes
2. distribute each collection's channel evenly across multiple
querynodes.

pr: #38143

---------

Signed-off-by: bigsheeper <[email protected]>
Co-authored-by: Wei Liu <[email protected]>

configs/milvus.yaml

@@ -339,6 +339,9 @@ queryCoord:
   rowCountFactor: 0.4 # the row count weight used when balancing segments among queryNodes
   segmentCountFactor: 0.4 # the segment count weight used when balancing segments among queryNodes
   globalSegmentCountFactor: 0.1 # the segment count weight used when balancing segments among queryNodes
+  # the channel count weight used when balancing channels among queryNodes, 
+  # 		A higher value reduces the likelihood of assigning channels from the same collection to the same QueryNode. Set to 1 to disable this feature.
+  collectionChannelCountFactor: 10
   segmentCountMaxSteps: 50 # segment count based plan generator max steps
   rowCountMaxSteps: 50 # segment count based plan generator max steps
   randomMaxSteps: 10 # segment count based plan generator max steps

internal/querycoordv2/balance/balance.go

@@ -58,7 +58,7 @@ func (chanPlan *ChannelAssignPlan) String() string {
 
 type Balance interface {
 	AssignSegment(collectionID int64, segments []*meta.Segment, nodes []int64, manualBalance bool) []SegmentAssignPlan
-	AssignChannel(channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan
+	AssignChannel(collectionID int64, channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan
 	BalanceReplica(replica *meta.Replica) ([]SegmentAssignPlan, []ChannelAssignPlan)
 }
 
@@ -103,7 +103,7 @@ func (b *RoundRobinBalancer) AssignSegment(collectionID int64, segments []*meta.
 	return ret
 }
 
-func (b *RoundRobinBalancer) AssignChannel(channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan {
+func (b *RoundRobinBalancer) AssignChannel(collectionID int64, channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan {
 	// skip out suspend node and stopping node during assignment, but skip this check for manual balance
 	if !manualBalance {
 		versionRangeFilter := semver.MustParseRange(">2.3.x")

internal/querycoordv2/balance/balance_test.go

@@ -174,7 +174,7 @@ func (suite *BalanceTestSuite) TestAssignChannel() {
 					suite.mockScheduler.EXPECT().GetChannelTaskDelta(c.nodeIDs[i], int64(-1)).Return(c.deltaCnts[i])
 				}
 			}
-			plans := suite.roundRobinBalancer.AssignChannel(c.assignments, c.nodeIDs, false)
+			plans := suite.roundRobinBalancer.AssignChannel(1, c.assignments, c.nodeIDs, false)
 			suite.ElementsMatch(c.expectPlans, plans)
 		})
 	}

internal/querycoordv2/balance/channel_level_score_balancer.go

@@ -143,7 +143,7 @@ func (b *ChannelLevelScoreBalancer) genStoppingChannelPlan(replica *meta.Replica
 	channelPlans := make([]ChannelAssignPlan, 0)
 	for _, nodeID := range offlineNodes {
 		dmChannels := b.dist.ChannelDistManager.GetByCollectionAndFilter(replica.GetCollectionID(), meta.WithNodeID2Channel(nodeID), meta.WithChannelName2Channel(channelName))
-		plans := b.AssignChannel(dmChannels, onlineNodes, false)
+		plans := b.AssignChannel(replica.GetCollectionID(), dmChannels, onlineNodes, false)
 		for i := range plans {
 			plans[i].From = nodeID
 			plans[i].Replica = replica
@@ -172,7 +172,7 @@ func (b *ChannelLevelScoreBalancer) genStoppingSegmentPlan(replica *meta.Replica
 
 func (b *ChannelLevelScoreBalancer) genSegmentPlan(br *balanceReport, replica *meta.Replica, channelName string, onlineNodes []int64) []SegmentAssignPlan {
 	segmentDist := make(map[int64][]*meta.Segment)
-	nodeItemsMap := b.convertToNodeItems(br, replica.GetCollectionID(), onlineNodes)
+	nodeItemsMap := b.convertToNodeItemsBySegment(br, replica.GetCollectionID(), onlineNodes)
 	if len(nodeItemsMap) == 0 {
 		return nil
 	}
@@ -258,7 +258,7 @@ func (b *ChannelLevelScoreBalancer) genChannelPlan(replica *meta.Replica, channe
 			return nil
 		}
 
-		channelPlans := b.AssignChannel(channelsToMove, nodeWithLessChannel, false)
+		channelPlans := b.AssignChannel(replica.GetCollectionID(), channelsToMove, nodeWithLessChannel, false)
 		for i := range channelPlans {
 			channelPlans[i].From = channelPlans[i].Channel.Node
 			channelPlans[i].Replica = replica

internal/querycoordv2/balance/rowcount_based_balancer.go

@@ -87,7 +87,7 @@ func (b *RowCountBasedBalancer) AssignSegment(collectionID int64, segments []*me
 
 // AssignSegment, when row count based balancer assign segments, it will assign channel to node with least global channel count.
 // try to make every query node has channel count
-func (b *RowCountBasedBalancer) AssignChannel(channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan {
+func (b *RowCountBasedBalancer) AssignChannel(collectionID int64, channels []*meta.DmChannel, nodes []int64, manualBalance bool) []ChannelAssignPlan {
 	// skip out suspend node and stopping node during assignment, but skip this check for manual balance
 	if !manualBalance {
 		versionRangeFilter := semver.MustParseRange(">2.3.x")
@@ -308,7 +308,7 @@ func (b *RowCountBasedBalancer) genStoppingChannelPlan(replica *meta.Replica, rw
 	channelPlans := make([]ChannelAssignPlan, 0)
 	for _, nodeID := range roNodes {
 		dmChannels := b.dist.ChannelDistManager.GetByCollectionAndFilter(replica.GetCollectionID(), meta.WithNodeID2Channel(nodeID))
-		plans := b.AssignChannel(dmChannels, rwNodes, false)
+		plans := b.AssignChannel(replica.GetCollectionID(), dmChannels, rwNodes, false)
 		for i := range plans {
 			plans[i].From = nodeID
 			plans[i].Replica = replica
@@ -346,7 +346,7 @@ func (b *RowCountBasedBalancer) genChannelPlan(br *balanceReport, replica *meta.
 			return nil
 		}
 
-		channelPlans := b.AssignChannel(channelsToMove, nodeWithLessChannel, false)
+		channelPlans := b.AssignChannel(replica.GetCollectionID(), channelsToMove, nodeWithLessChannel, false)
 		for i := range channelPlans {
 			channelPlans[i].From = channelPlans[i].Channel.Node
 			channelPlans[i].Replica = replica