madrob commented on a change in pull request #2429:
URL: https://github.com/apache/lucene-solr/pull/2429#discussion_r583176395
##########
File path: lucene/core/src/java/org/apache/lucene/util/BytesRefHash.java
##########
@@ -31,18 +31,21 @@
* to the id is encapsulated inside {@link BytesRefHash} and is guaranteed to
be increased for each
* added {@link BytesRef}.
*
+ * <p><strong>Note that this implementation is not synchronized.</strong> If
multiple threads access
+ * a {@link BytesRefHash} instance concurrently, and at least one of the
threads modifies it
+ * structurally, it <i>must</i> be synchronized externally. (A structural
modification is any
+ * operation on the map except operations explicitly listed in {@link
UnmodifiableBytesRefHash}
Review comment:
not a map
##########
File path: lucene/core/src/test/org/apache/lucene/util/TestBytesRefHash.java
##########
@@ -267,6 +271,71 @@ public void testFind() throws Exception {
}
}
+ @Test
+ public void testConcurrentAccessToUnmodifiableBytesRefHash() throws
Exception {
+ int num = atLeast(2);
+ for (int j = 0; j < num; j++) {
+ int numStrings = 797;
+ List<String> strings = new ArrayList<>(numStrings);
+ for (int i = 0; i < numStrings; i++) {
+ final String str = TestUtil.randomRealisticUnicodeString(random(), 1,
1000);
+ hash.add(new BytesRef(str));
+ assertTrue(strings.add(str));
+ }
+ int hashSize = hash.size();
+
+ UnmodifiableBytesRefHash unmodifiableHash = hash;
+
+ AtomicInteger notFound = new AtomicInteger();
+ AtomicInteger notEquals = new AtomicInteger();
+ AtomicInteger wrongSize = new AtomicInteger();
+ int numThreads = 10;
+ CountDownLatch latch = new CountDownLatch(numThreads);
+ Thread[] threads = new Thread[numThreads];
+ for (int i = 0; i < threads.length; i++) {
+ int loops = atLeast(100);
+ threads[i] =
+ new Thread(
+ () -> {
+ BytesRef scratch = new BytesRef();
+ latch.countDown();
+ try {
+ latch.await();
+ } catch (InterruptedException e) {
Review comment:
This should fail the test?
##########
File path: lucene/core/src/java/org/apache/lucene/util/BytesRefHash.java
##########
@@ -31,18 +31,21 @@
* to the id is encapsulated inside {@link BytesRefHash} and is guaranteed to
be increased for each
* added {@link BytesRef}.
*
+ * <p><strong>Note that this implementation is not synchronized.</strong> If
multiple threads access
+ * a {@link BytesRefHash} instance concurrently, and at least one of the
threads modifies it
+ * structurally, it <i>must</i> be synchronized externally. (A structural
modification is any
+ * operation on the map except operations explicitly listed in {@link
UnmodifiableBytesRefHash}
+ * interface).
+ *
* <p>Note: The maximum capacity {@link BytesRef} instance passed to {@link
#add(BytesRef)} must not
* be longer than {@link ByteBlockPool#BYTE_BLOCK_SIZE}-2. The internal
storage is limited to 2GB
* total byte storage.
*
* @lucene.internal
*/
-public final class BytesRefHash implements Accountable {
+public final class BytesRefHash implements Accountable,
UnmodifiableBytesRefHash {
Review comment:
this feels weird
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