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c63755c316
Previously the -maxConcurrentInserts was limiting the number of established client connections, which write data to VictoriaMetrics. Some of these connections could be idle. Such connections do not consume big amounts of CPU and RAM, so there is a little sense in limiting the number of such connections. So now the -maxConcurrentInserts command-line option limits the number of concurrently executed insert requests, not including idle connections. It is recommended removing -maxConcurrentInserts command-line option, since the default value for this option should work good for most cases.
132 lines
3.5 KiB
Go
132 lines
3.5 KiB
Go
package writeconcurrencylimiter
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import (
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"flag"
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"fmt"
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"io"
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"net/http"
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"sync"
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"time"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/cgroup"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
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"github.com/VictoriaMetrics/VictoriaMetrics/lib/timerpool"
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"github.com/VictoriaMetrics/metrics"
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)
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var (
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maxConcurrentInserts = flag.Int("maxConcurrentInserts", 2*cgroup.AvailableCPUs(), "The maximum number of concurrent insert requests. "+
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"Default value should work for most cases, since it minimizes the overhead. See also -insert.maxQueueDuration")
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maxQueueDuration = flag.Duration("insert.maxQueueDuration", time.Minute, "The maximum duration to wait in the queue when -maxConcurrentInserts "+
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"concurrent insert requests are already executed")
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)
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// Reader is a reader, which increases the concurrency after the first Read() call
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//
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// The concurrency can be reduced by calling DecConcurrency().
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// Then the concurrency is increased after the next Read() call.
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type Reader struct {
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r io.Reader
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increasedConcurrency bool
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}
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// GetReader returns the Reader for r.
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//
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// The PutReader() must be called when the returned Reader is no longer needed.
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func GetReader(r io.Reader) *Reader {
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v := readerPool.Get()
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if v == nil {
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return &Reader{
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r: r,
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}
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}
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rr := v.(*Reader)
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rr.r = r
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return rr
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}
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// PutReader returns the r to the pool.
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//
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// It decreases the concurrency if r has increased concurrency.
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func PutReader(r *Reader) {
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r.DecConcurrency()
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r.r = nil
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readerPool.Put(r)
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}
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var readerPool sync.Pool
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// Read implements io.Reader.
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//
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// It increases concurrency after the first call or after the next call after DecConcurrency() call.
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func (r *Reader) Read(p []byte) (int, error) {
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n, err := r.r.Read(p)
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if !r.increasedConcurrency {
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if err := incConcurrency(); err != nil {
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return 0, err
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}
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r.increasedConcurrency = true
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}
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return n, err
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}
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// DecConcurrency decreases the concurrency, so it could be increased again after the next Read() call.
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func (r *Reader) DecConcurrency() {
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if r.increasedConcurrency {
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decConcurrency()
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r.increasedConcurrency = false
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}
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}
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func initConcurrencyLimitCh() {
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concurrencyLimitCh = make(chan struct{}, *maxConcurrentInserts)
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}
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var (
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concurrencyLimitCh chan struct{}
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concurrencyLimitChOnce sync.Once
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)
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func incConcurrency() error {
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concurrencyLimitChOnce.Do(initConcurrencyLimitCh)
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select {
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case concurrencyLimitCh <- struct{}{}:
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return nil
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default:
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}
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concurrencyLimitReached.Inc()
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t := timerpool.Get(*maxQueueDuration)
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select {
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case concurrencyLimitCh <- struct{}{}:
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timerpool.Put(t)
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return nil
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case <-t.C:
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timerpool.Put(t)
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concurrencyLimitTimeout.Inc()
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return &httpserver.ErrorWithStatusCode{
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Err: fmt.Errorf("cannot process insert request for %.3f seconds because %d concurrent insert requests are already executed. "+
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"Possible solutions: to reduce workload; to increase compute resources at the server; "+
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"to increase -insert.maxQueueDuration; to increase -maxConcurrentInserts",
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maxQueueDuration.Seconds(), *maxConcurrentInserts),
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StatusCode: http.StatusServiceUnavailable,
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}
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}
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}
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func decConcurrency() {
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<-concurrencyLimitCh
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}
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var (
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concurrencyLimitReached = metrics.NewCounter(`vm_concurrent_insert_limit_reached_total`)
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concurrencyLimitTimeout = metrics.NewCounter(`vm_concurrent_insert_limit_timeout_total`)
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_ = metrics.NewGauge(`vm_concurrent_insert_capacity`, func() float64 {
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return float64(cap(concurrencyLimitCh))
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})
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_ = metrics.NewGauge(`vm_concurrent_insert_current`, func() float64 {
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return float64(len(concurrencyLimitCh))
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})
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)
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