vanzin commented on a change in pull request #24616: [SPARK-27726] [Core] Fix
performance of ElementTrackingStore deletes when using InMemoryStore under high
loads
URL: https://github.com/apache/spark/pull/24616#discussion_r285313162
##########
File path:
common/kvstore/src/main/java/org/apache/spark/util/kvstore/InMemoryStore.java
##########
@@ -126,64 +134,149 @@ public void close() {
return (Comparable<Object>) in;
}
- private static class InstanceList {
+ @SuppressWarnings("unchecked")
+ private static <T> KVStoreView<T> emptyView() {
+ return (InMemoryView<T>) InMemoryView.EMPTY_VIEW;
+ }
+
+ /**
+ * Encapsulates ConcurrentHashMap so that the typing in and out of the map
strictly maps a
+ * class of type T to an InstanceList of type T.
+ */
+ private static class InMemoryLists {
+ private ConcurrentMap<Class<?>, InstanceList<?>> data = new
ConcurrentHashMap<>();
+
+ @SuppressWarnings("unchecked")
+ public <T> InstanceList<T> get(Class<T> type) {
+ return (InstanceList<T>) data.get(type);
+ }
+
+ @SuppressWarnings("unchecked")
+ public <T> void write(T value) throws Exception {
+ InstanceList<T> list =
+ (InstanceList<T>) data.computeIfAbsent(value.getClass(),
InstanceList::new);
+ list.put(value);
+ }
+
+ public void clear() {
+ data.clear();
+ }
+ }
+
+ private static class InstanceList<T> {
+
+ /**
+ * A BiConsumer to control multi-entity removal. We use this in a forEach
rather than an
+ * iterator because there is a bug in jdk8 which affects remove() on all
concurrent map
+ * iterators. https://bugs.openjdk.java.net/browse/JDK-8078645
+ */
+ private static class CountingRemoveIfForEach<T> implements
BiConsumer<Comparable<Object>, T> {
+ private final ConcurrentMap<Comparable<Object>, T> data;
+ private final Predicate<? super T> filter;
+
+ /**
+ * Keeps a count of the number of elements removed. This count is not
currently surfaced
+ * to clients of KVStore as Java's generic removeAll() construct returns
only a boolean,
+ * but I found it handy to have the count of elements removed while
debugging; a count being
+ * no more complicated than a boolean, I've retained that behavior here,
even though there
+ * is no current requirement.
+ */
+ private int count = 0;
+
+ CountingRemoveIfForEach(
+ ConcurrentMap<Comparable<Object>, T> data,
+ Predicate<? super T> filter) {
+ this.data = data;
+ this.filter = filter;
+ }
+
+ public void accept(Comparable<Object> key, T value) {
+ if (filter.test(value)) {
+ if (data.remove(key, value)) {
+ count++;
+ }
+ }
+ }
+
+ public int count() { return count; }
+ }
private final KVTypeInfo ti;
private final KVTypeInfo.Accessor naturalKey;
- private final ConcurrentMap<Comparable<Object>, Object> data;
+ private final ConcurrentMap<Comparable<Object>, T> data;
- private int size;
-
- private InstanceList(Class<?> type) throws Exception {
- this.ti = new KVTypeInfo(type);
+ private InstanceList(Class<?> klass) {
+ this.ti = new KVTypeInfo(klass);
this.naturalKey = ti.getAccessor(KVIndex.NATURAL_INDEX_NAME);
this.data = new ConcurrentHashMap<>();
- this.size = 0;
}
KVTypeInfo.Accessor getIndexAccessor(String indexName) {
return ti.getAccessor(indexName);
}
- public Object get(Object key) {
+ int countingRemoveAllByIndexValues(String index, Collection<?>
indexValues) {
+ Predicate<? super T> filter = getPredicate(ti.getAccessor(index),
indexValues);
+ CountingRemoveIfForEach<T> callback = new
CountingRemoveIfForEach<>(data, filter);
+
+ data.forEach(callback);
+ return callback.count();
+ }
+
+ public T get(Object key) {
return data.get(asKey(key));
}
- public void put(Object value) throws Exception {
- Preconditions.checkArgument(ti.type().equals(value.getClass()),
- "Unexpected type: %s", value.getClass());
- if (data.put(asKey(naturalKey.get(value)), value) == null) {
- size++;
- }
+ public void put(T value) throws Exception {
+ data.put(asKey(naturalKey.get(value)), value);
}
public void delete(Object key) {
- if (data.remove(asKey(key)) != null) {
- size--;
- }
+ data.remove(asKey(key));
}
public int size() {
- return size;
+ return data.size();
}
- @SuppressWarnings("unchecked")
- public <T> InMemoryView<T> view(Class<T> type) {
- Preconditions.checkArgument(ti.type().equals(type), "Unexpected type:
%s", type);
- Collection<T> all = (Collection<T>) data.values();
- return new InMemoryView<>(type, all, ti);
+ public InMemoryView<T> view() {
+ return new InMemoryView<>(data.values(), ti);
+ }
+
+ private static <T> Predicate<? super T> getPredicate(
+ KVTypeInfo.Accessor getter,
+ Collection<?> keys) {
Review comment:
s/keys/values
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