6d805a13cf
simplify the topic view counter
129 lines
3.2 KiB
Go
129 lines
3.2 KiB
Go
package counters
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import (
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"database/sql"
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"sync"
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"sync/atomic"
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c "github.com/Azareal/Gosora/common"
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"github.com/Azareal/Gosora/query_gen"
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"github.com/pkg/errors"
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)
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var TopicViewCounter *DefaultTopicViewCounter
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// TODO: Use two odd-even maps for now, and move to something more concurrent later, maybe a sharded map?
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type DefaultTopicViewCounter struct {
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oddTopics map[int]*RWMutexCounterBucket // map[tid]struct{counter,sync.RWMutex}
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evenTopics map[int]*RWMutexCounterBucket
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oddLock sync.RWMutex
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evenLock sync.RWMutex
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update *sql.Stmt
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}
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func NewDefaultTopicViewCounter() (*DefaultTopicViewCounter, error) {
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acc := qgen.NewAcc()
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co := &DefaultTopicViewCounter{
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oddTopics: make(map[int]*RWMutexCounterBucket),
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evenTopics: make(map[int]*RWMutexCounterBucket),
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update: acc.Update("topics").Set("views = views + ?").Where("tid = ?").Prepare(),
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}
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c.AddScheduledFifteenMinuteTask(co.Tick) // Who knows how many topics we have queued up, we probably don't want this running too frequently
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//c.AddScheduledSecondTask(co.Tick)
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c.AddShutdownTask(co.Tick)
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return co, acc.FirstError()
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}
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func (co *DefaultTopicViewCounter) Tick() error {
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// TODO: Fold multiple 1 view topics into one query
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cLoop := func(l *sync.RWMutex, m map[int]*RWMutexCounterBucket) error {
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l.RLock()
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for topicID, topic := range m {
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l.RUnlock()
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var count int
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topic.RLock()
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count = topic.counter
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topic.RUnlock()
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// TODO: Only delete the bucket when it's zero to avoid hitting popular topics?
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l.Lock()
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delete(m, topicID)
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l.Unlock()
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err := co.insertChunk(count, topicID)
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if err != nil {
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return errors.Wrap(errors.WithStack(err),"topicview counter")
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}
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l.RLock()
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}
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l.RUnlock()
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return nil
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}
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err := cLoop(&co.oddLock,co.oddTopics)
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if err != nil {
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return err
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}
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return cLoop(&co.evenLock,co.evenTopics)
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}
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// TODO: Optimise this further. E.g. Using IN() on every one view topic. Rinse and repeat for two views, three views, four views and five views.
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func (co *DefaultTopicViewCounter) insertChunk(count int, topicID int) error {
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if count == 0 {
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return nil
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}
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c.DebugLogf("Inserting %d views into topic %d", count, topicID)
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_, err := co.update.Exec(count, topicID)
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if err == sql.ErrNoRows {
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return nil
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} else if err != nil {
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return err
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}
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// TODO: Add a way to disable this for extra speed ;)
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tcache := c.Topics.GetCache()
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if tcache != nil {
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topic, err := tcache.Get(topicID)
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if err == sql.ErrNoRows {
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return nil
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} else if err != nil {
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return err
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}
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atomic.AddInt64(&topic.ViewCount, int64(count))
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}
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return nil
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}
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func (co *DefaultTopicViewCounter) Bump(topicID int) {
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// Is the ID even?
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if topicID%2 == 0 {
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co.evenLock.RLock()
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topic, ok := co.evenTopics[topicID]
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co.evenLock.RUnlock()
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if ok {
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topic.Lock()
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topic.counter++
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topic.Unlock()
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} else {
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co.evenLock.Lock()
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co.evenTopics[topicID] = &RWMutexCounterBucket{counter: 1}
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co.evenLock.Unlock()
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}
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return
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}
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co.oddLock.RLock()
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topic, ok := co.oddTopics[topicID]
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co.oddLock.RUnlock()
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if ok {
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topic.Lock()
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topic.counter++
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topic.Unlock()
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} else {
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co.oddLock.Lock()
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co.oddTopics[topicID] = &RWMutexCounterBucket{counter: 1}
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co.oddLock.Unlock()
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}
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}
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