119 lines
3.1 KiB
Go
119 lines
3.1 KiB
Go
package counters
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import (
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"database/sql"
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"sync"
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".."
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"../../query_gen/lib"
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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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counter := &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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common.AddScheduledFifteenMinuteTask(counter.Tick) // Who knows how many topics we have queued up, we probably don't want this running too frequently
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//common.AddScheduledSecondTask(counter.Tick)
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common.AddShutdownTask(counter.Tick)
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return counter, acc.FirstError()
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}
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func (counter *DefaultTopicViewCounter) Tick() error {
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// TODO: Fold multiple 1 view topics into one query
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counter.oddLock.RLock()
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oddTopics := counter.oddTopics
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counter.oddLock.RUnlock()
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for topicID, topic := range oddTopics {
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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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counter.oddLock.Lock()
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delete(counter.oddTopics, topicID)
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counter.oddLock.Unlock()
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err := counter.insertChunk(count, topicID)
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if err != nil {
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return err
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}
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}
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counter.evenLock.RLock()
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evenTopics := counter.evenTopics
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counter.evenLock.RUnlock()
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for topicID, topic := range evenTopics {
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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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counter.evenLock.Lock()
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delete(counter.evenTopics, topicID)
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counter.evenLock.Unlock()
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err := counter.insertChunk(count, topicID)
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if err != nil {
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return err
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}
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}
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return nil
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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 (counter *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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common.DebugLogf("Inserting %d views into topic %d", count, topicID)
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_, err := counter.update.Exec(count, topicID)
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return err
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}
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func (counter *DefaultTopicViewCounter) Bump(topicID int) {
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// Is the ID even?
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if topicID%2 == 0 {
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counter.evenLock.RLock()
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topic, ok := counter.evenTopics[topicID]
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counter.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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counter.evenLock.Lock()
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counter.evenTopics[topicID] = &RWMutexCounterBucket{counter: 1}
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counter.evenLock.Unlock()
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}
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return
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}
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counter.oddLock.RLock()
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topic, ok := counter.oddTopics[topicID]
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counter.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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counter.oddLock.Lock()
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counter.oddTopics[topicID] = &RWMutexCounterBucket{counter: 1}
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counter.oddLock.Unlock()
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}
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}
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