milvus/internal/streamingnode/server/flusher/flusherimpl/vchannel_checkpoint.go

139 lines
3.8 KiB
Go

package flusherimpl
import (
"container/heap"
"github.com/cockroachdb/errors"
"github.com/milvus-io/milvus/pkg/v2/streaming/util/message"
)
var (
errVChannelAlreadyExists = errors.New("vchannel already exists")
errVChannelNotFound = errors.New("vchannel not found")
errRollbackCheckpoint = errors.New("rollback a checkpoint is not allow")
)
// newVChannelCheckpointManager creates a new vchannelCheckpointManager
func newVChannelCheckpointManager(exists map[string]message.MessageID) *vchannelCheckpointManager {
index := make(map[string]*vchannelCheckpoint)
checkpointHeap := make(vchannelCheckpointHeap, 0, len(exists))
for vchannel, checkpoint := range exists {
index[vchannel] = &vchannelCheckpoint{
vchannel: vchannel,
checkpoint: checkpoint,
index: len(checkpointHeap),
}
checkpointHeap = append(checkpointHeap, index[vchannel])
}
heap.Init(&checkpointHeap)
return &vchannelCheckpointManager{
checkpointHeap: checkpointHeap,
index: index,
}
}
// vchannelCheckpointManager is the struct to manage the checkpoints of all vchannels at one pchannel
type vchannelCheckpointManager struct {
checkpointHeap vchannelCheckpointHeap
index map[string]*vchannelCheckpoint
}
// Add adds a vchannel with a checkpoint to the manager
func (m *vchannelCheckpointManager) Add(vchannel string, checkpoint message.MessageID) error {
if _, ok := m.index[vchannel]; ok {
return errVChannelAlreadyExists
}
vc := &vchannelCheckpoint{
vchannel: vchannel,
checkpoint: checkpoint,
}
heap.Push(&m.checkpointHeap, vc)
m.index[vchannel] = vc
return nil
}
// Drop removes a vchannel from the manager
func (m *vchannelCheckpointManager) Drop(vchannel string) error {
vc, ok := m.index[vchannel]
if !ok {
return errVChannelNotFound
}
heap.Remove(&m.checkpointHeap, vc.index)
delete(m.index, vchannel)
return nil
}
// Update updates the checkpoint of a vchannel
func (m *vchannelCheckpointManager) Update(vchannel string, checkpoint message.MessageID) error {
previous, ok := m.index[vchannel]
if !ok {
return errVChannelNotFound
}
if checkpoint.LT(previous.checkpoint) {
return errors.Wrapf(errRollbackCheckpoint, "checkpoint: %s, previous: %s", checkpoint, previous.checkpoint)
}
if checkpoint.EQ(previous.checkpoint) {
return nil
}
m.checkpointHeap.Update(previous, checkpoint)
return nil
}
// Len returns the number of vchannels
func (m *vchannelCheckpointManager) Len() int {
return len(m.checkpointHeap)
}
// MinimumCheckpoint returns the minimum checkpoint of all vchannels
func (m *vchannelCheckpointManager) MinimumCheckpoint() message.MessageID {
if len(m.checkpointHeap) == 0 {
return nil
}
return m.checkpointHeap[0].checkpoint
}
// vchannelCheckpoint is the struct to hold the checkpoint of a vchannel
type vchannelCheckpoint struct {
vchannel string
checkpoint message.MessageID
index int
}
// A vchannelCheckpointHeap implements heap.Interface and holds Items.
type vchannelCheckpointHeap []*vchannelCheckpoint
func (pq vchannelCheckpointHeap) Len() int { return len(pq) }
func (pq vchannelCheckpointHeap) Less(i, j int) bool {
return pq[i].checkpoint.LT(pq[j].checkpoint)
}
func (pq vchannelCheckpointHeap) Swap(i, j int) {
pq[i], pq[j] = pq[j], pq[i]
pq[i].index = i
pq[j].index = j
}
func (pq *vchannelCheckpointHeap) Push(x any) {
n := len(*pq)
item := x.(*vchannelCheckpoint)
item.index = n
*pq = append(*pq, item)
}
func (pq *vchannelCheckpointHeap) Pop() any {
old := *pq
n := len(old)
item := old[n-1]
old[n-1] = nil // don't stop the GC from reclaiming the item eventually
item.index = -1 // for safety
*pq = old[0 : n-1]
return item
}
func (pq *vchannelCheckpointHeap) Update(item *vchannelCheckpoint, checkpoint message.MessageID) {
item.checkpoint = checkpoint
heap.Fix(pq, item.index)
}