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lazily initialize ReservoirCells (#6851) 

Co-authored-by: jack-berg <34418638+jack-berg@users.noreply.github.com>
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Eugene Ma 2024-11-18 13:56:03 -08:00 committed by GitHub
parent cde3d45f04
commit e0a6e64fc7
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1 changed files with 22 additions and 6 deletions
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28
sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/internal/exemplar/FixedSizeExemplarReservoir.java
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@ -13,13 +13,16 @@ import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.function.BiFunction;
import javax.annotation.Nullable;
/** Base for fixed-size reservoir sampling of Exemplars. */
abstract class FixedSizeExemplarReservoir<T extends ExemplarData> implements ExemplarReservoir<T> {
private final ReservoirCell[] storage;
@Nullable private ReservoirCell[] storage;
private final ReservoirCellSelector reservoirCellSelector;
private final BiFunction<ReservoirCell, Attributes, T> mapAndResetCell;
private final int size;
private final Clock clock;
private volatile boolean hasMeasurements = false;
/** Instantiates an exemplar reservoir of fixed size. */
@ -28,16 +31,18 @@ abstract class FixedSizeExemplarReservoir<T extends ExemplarData> implements Exe
int size,
ReservoirCellSelector reservoirCellSelector,
BiFunction<ReservoirCell, Attributes, T> mapAndResetCell) {
this.storage = new ReservoirCell[size];
for (int i = 0; i < size; ++i) {
this.storage[i] = new ReservoirCell(clock);
}
this.storage = null; // lazily initialize to avoid allocations
this.size = size;
this.clock = clock;
this.reservoirCellSelector = reservoirCellSelector;
this.mapAndResetCell = mapAndResetCell;
}
@Override
public void offerLongMeasurement(long value, Attributes attributes, Context context) {
if (storage == null) {
storage = initStorage();
}
int bucket = reservoirCellSelector.reservoirCellIndexFor(storage, value, attributes, context);
if (bucket != -1) {
this.storage[bucket].recordLongMeasurement(value, attributes, context);
@ -47,6 +52,9 @@ abstract class FixedSizeExemplarReservoir<T extends ExemplarData> implements Exe
@Override
public void offerDoubleMeasurement(double value, Attributes attributes, Context context) {
if (storage == null) {
storage = initStorage();
}
int bucket = reservoirCellSelector.reservoirCellIndexFor(storage, value, attributes, context);
if (bucket != -1) {
this.storage[bucket].recordDoubleMeasurement(value, attributes, context);
@ -54,9 +62,17 @@ abstract class FixedSizeExemplarReservoir<T extends ExemplarData> implements Exe
}
}
private ReservoirCell[] initStorage() {
ReservoirCell[] storage = new ReservoirCell[this.size];
for (int i = 0; i < size; ++i) {
storage[i] = new ReservoirCell(this.clock);
}
return storage;
}
@Override
public List<T> collectAndReset(Attributes pointAttributes) {
if (!hasMeasurements) {
if (!hasMeasurements || storage == null) {
return Collections.emptyList();
}
// Note: we are collecting exemplars from buckets piecemeal, but we