Caideyipi commented on code in PR #16425:
URL: https://github.com/apache/iotdb/pull/16425#discussion_r2357741353
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iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/analyze/cache/schema/dualkeycache/impl/FIFOCacheEntryManager.java:
##########
@@ -171,28 +186,40 @@ public int hashCode() {
private static class FIFOLinkedList<SK, V> {
// head.next is the newest
- private final FIFOCacheEntry head;
- private final FIFOCacheEntry tail;
+ private final FIFOCacheEntry<SK, V> head;
+ private final FIFOCacheEntry<SK, V> tail;
public FIFOLinkedList() {
- head = new FIFOCacheEntry(null, null, null);
- tail = new FIFOCacheEntry(null, null, null);
+ head = new FIFOCacheEntry<>(null, null, null);
+ tail = new FIFOCacheEntry<>(null, null, null);
head.next = tail;
tail.pre = head;
}
- synchronized void add(FIFOCacheEntry cacheEntry) {
- cacheEntry.next = head.next;
+ synchronized void add(final FIFOCacheEntry<SK, V> cacheEntry) {
+ FIFOCacheEntry<SK, V> nextEntry;
+
+ do {
+ nextEntry = head.next;
+ } while (nextEntry.isInvalidated.get());
Review Comment:
This is because the "invalidate" does not take lock, and we need
"isInvalidated" to protect the correctness. The head.next is supposed to be
altered by the invalidation thread.
##########
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/analyze/cache/schema/dualkeycache/impl/FIFOCacheEntryManager.java:
##########
@@ -171,28 +186,40 @@ public int hashCode() {
private static class FIFOLinkedList<SK, V> {
// head.next is the newest
- private final FIFOCacheEntry head;
- private final FIFOCacheEntry tail;
+ private final FIFOCacheEntry<SK, V> head;
+ private final FIFOCacheEntry<SK, V> tail;
public FIFOLinkedList() {
- head = new FIFOCacheEntry(null, null, null);
- tail = new FIFOCacheEntry(null, null, null);
+ head = new FIFOCacheEntry<>(null, null, null);
+ tail = new FIFOCacheEntry<>(null, null, null);
head.next = tail;
tail.pre = head;
}
- synchronized void add(FIFOCacheEntry cacheEntry) {
- cacheEntry.next = head.next;
+ synchronized void add(final FIFOCacheEntry<SK, V> cacheEntry) {
+ FIFOCacheEntry<SK, V> nextEntry;
+
+ do {
+ nextEntry = head.next;
+ } while (nextEntry.isInvalidated.get());
+
+ cacheEntry.next = nextEntry;
cacheEntry.pre = head;
- head.next.pre = cacheEntry;
+ nextEntry.pre = cacheEntry;
head.next = cacheEntry;
}
- synchronized FIFOCacheEntry evict() {
- if (tail.pre == head) {
- return null;
- }
- FIFOCacheEntry cacheEntry = tail.pre;
+ synchronized FIFOCacheEntry<SK, V> evict() {
+ FIFOCacheEntry<SK, V> cacheEntry;
+
+ do {
+ cacheEntry = tail.pre;
+ if (cacheEntry == head) {
+ return null;
+ }
+
+ } while (cacheEntry.isInvalidated.compareAndSet(false, true));
Review Comment:
Same as above
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