// scanLoop loops endlessly, scanning through ranges available via
// the range iterator, or until the scanner is stopped. The iteration
// is paced to complete a full scan in approximately the scan interval.
func (rs *rangeScanner) scanLoop(clock *hlc.Clock, stopper *util.Stopper) {
start := time.Now()
stats := &storeStats{}
for {
elapsed := time.Now().Sub(start)
remainingNanos := rs.interval.Nanoseconds() - elapsed.Nanoseconds()
if remainingNanos < 0 {
remainingNanos = 0
}
nextIteration := time.Duration(remainingNanos)
if count := rs.iter.EstimatedCount(); count > 0 {
nextIteration = time.Duration(remainingNanos / int64(count))
}
log.V(6).Infof("next range scan iteration in %s", nextIteration)
select {
case <-time.After(nextIteration):
rng := rs.iter.Next()
if rng != nil {
// Try adding range to all queues.
for _, q := range rs.queues {
q.MaybeAdd(rng, clock.Now())
}
stats.RangeCount++
stats.MVCC.Accumulate(rng.stats.GetMVCC())
} else {
// Otherwise, we're done with the iteration. Reset iteration and start time.
rs.iter.Reset()
start = time.Now()
// Increment iteration counter.
atomic.AddInt64(&rs.count, 1)
// Store the most recent scan results in the scanner's stats.
atomic.StorePointer(&rs.stats, unsafe.Pointer(stats))
stats = &storeStats{}
log.V(6).Infof("reset range scan iteration")
}
case rng := <-rs.removed:
// Remove range from all queues as applicable.
for _, q := range rs.queues {
q.MaybeRemove(rng)
}
log.V(6).Infof("removed range %s", rng)
case <-stopper.ShouldStop():
// Exit the loop.
stopper.SetStopped()
return
}
}
}
func (tq *testQueue) Start(clock *hlc.Clock, stopper *util.Stopper) {
stopper.Add(1)
go func() {
for {
select {
case <-time.After(1 * time.Millisecond):
tq.Lock()
if len(tq.ranges) > 0 {
tq.ranges = tq.ranges[1:]
tq.processed++
}
tq.Unlock()
case <-stopper.ShouldStop():
tq.Lock()
tq.done = true
tq.Unlock()
stopper.SetStopped()
return
}
}
}()
}
