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lib/storage: prevent from running identical heavy tag filters in concurrent queries when measuring the number of loops for such tag filter.

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This should reduce CPU usage spikes when measuring the number of loops needed for heavy tag filters
This commit is contained in:
Aliaksandr Valialkin 2021-02-18 13:56:50 +02:00
parent 711f8a5b8d
commit e540c02014
1 changed files with 27 additions and 17 deletions
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44
lib/storage/index_db.go
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@ -2796,10 +2796,20 @@ func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilter
for i := range tfs.tfs {
tf := &tfs.tfs[i]
loopsCount, lastQueryTimestamp := is.getLoopsCountAndTimestampForDateFilter(date, tf)
origLoopsCount := loopsCount
if currentTime > lastQueryTimestamp+60*60 {
// Reset loopsCount to 0 every hour for collecting updated stats for the tf.
loopsCount = 0
}
if loopsCount == 0 {
// Prevent from possible thundering herd issue when heavy tf is executed from multiple concurrent queries
// by temporary persisting its position in the tag filters list.
if origLoopsCount == 0 {
origLoopsCount = 10e6
}
lastQueryTimestamp = 0
is.storeLoopsCountForDateFilter(date, tf, origLoopsCount, lastQueryTimestamp)
}
tfws[i] = tagFilterWithWeight{
tf: tf,
loopsCount: loopsCount,
@ -2826,7 +2836,8 @@ func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilter
tfwsRemaining = append(tfwsRemaining, tfw)
continue
}
m, err := is.getMetricIDsForDateTagFilter(tf, tfw.lastQueryTimestamp, date, nil, tfs.commonPrefix, maxDateMetrics)
m, loopsCount, err := is.getMetricIDsForDateTagFilter(tf, date, nil, tfs.commonPrefix, maxDateMetrics)
is.storeLoopsCountForDateFilter(date, tf, loopsCount, tfw.lastQueryTimestamp)
if err != nil {
return nil, err
}
@ -2880,9 +2891,12 @@ func (is *indexSearch) getMetricIDsForDateAndFilters(date uint64, tfs *TagFilter
// It should be faster performing metricName match on the remaining filters
// instead of scanning big number of entries in the inverted index for these filters.
tfsPostponed = append(tfsPostponed, tf)
// Store stats for non-executed tf, since it could be updated during protection from thundered herd.
is.storeLoopsCountForDateFilter(date, tf, tfw.loopsCount, tfw.lastQueryTimestamp)
continue
}
m, err := is.getMetricIDsForDateTagFilter(tf, tfw.lastQueryTimestamp, date, metricIDs, tfs.commonPrefix, maxDateMetrics)
m, loopsCount, err := is.getMetricIDsForDateTagFilter(tf, date, metricIDs, tfs.commonPrefix, maxDateMetrics)
is.storeLoopsCountForDateFilter(date, tf, loopsCount, tfw.lastQueryTimestamp)
if err != nil {
return nil, err
}
@ -3058,8 +3072,7 @@ func (is *indexSearch) hasDateMetricID(date, metricID uint64) (bool, error) {
return true, nil
}
func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, lastQueryTimestamp, date uint64,
filter *uint64set.Set, commonPrefix []byte, maxMetrics int) (*uint64set.Set, error) {
func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, date uint64, filter *uint64set.Set, commonPrefix []byte, maxMetrics int) (*uint64set.Set, uint64, error) {
// Augument tag filter prefix for per-date search instead of global search.
if !bytes.HasPrefix(tf.prefix, commonPrefix) {
logger.Panicf("BUG: unexpected tf.prefix %q; must start with commonPrefix %q", tf.prefix, commonPrefix)
@ -3073,25 +3086,16 @@ func (is *indexSearch) getMetricIDsForDateTagFilter(tf *tagFilter, lastQueryTime
tfNew.prefix = kb.B
metricIDs, loopsCount, err := is.getMetricIDsForTagFilter(&tfNew, filter, maxMetrics)
kbPool.Put(kb)
currentTimestamp := fasttime.UnixTimestamp()
if currentTimestamp > lastQueryTimestamp+5 {
// The cache already contains quite fresh entry for the current (date, tf).
// Do not update it too frequently.
return metricIDs, err
}
// Store the loopsCount for tag filter in the cache in order to sort tag filters
// in ascending durations on the next search.
if err != nil {
// Set high loopsCount for failing filter, so it is moved to the end of filter list.
loopsCount = 1 << 30
loopsCount = 1e9
}
if metricIDs.Len() >= maxMetrics {
// Increase loopsCount for tag filter matching too many metrics,
// So next time it is moved to the end of filter list.
loopsCount *= 2
}
is.storeLoopsCountAndTimestampForDateFilter(date, tf, loopsCount, currentTimestamp)
return metricIDs, err
return metricIDs, loopsCount, err
}
func (is *indexSearch) getLoopsCountAndTimestampForDateFilter(date uint64, tf *tagFilter) (uint64, uint64) {
@ -3107,11 +3111,17 @@ func (is *indexSearch) getLoopsCountAndTimestampForDateFilter(date uint64, tf *t
return loopsCount, timestamp
}
func (is *indexSearch) storeLoopsCountAndTimestampForDateFilter(date uint64, tf *tagFilter, loopsCount, timestamp uint64) {
func (is *indexSearch) storeLoopsCountForDateFilter(date uint64, tf *tagFilter, loopsCount, prevTimestamp uint64) {
currentTimestamp := fasttime.UnixTimestamp()
if currentTimestamp < prevTimestamp+5 {
// The cache already contains quite fresh entry for the current (date, tf).
// Do not update it too frequently.
return
}
is.kb.B = appendDateTagFilterCacheKey(is.kb.B[:0], date, tf)
kb := kbPool.Get()
kb.B = encoding.MarshalUint64(kb.B[:0], loopsCount)
kb.B = encoding.MarshalUint64(kb.B, timestamp)
kb.B = encoding.MarshalUint64(kb.B, currentTimestamp)
is.db.durationsPerDateTagFilterCache.Set(is.kb.B, kb.B)
kbPool.Put(kb)
}