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ARTEMIS-3049 Reduce live page lookup cost

This commit is contained in:
franz1981 2021-01-04 15:10:49 +01:00 committed by Clebert Suconic
parent 884336f08c
commit 19b04531c6
4 changed files with 108 additions and 42 deletions
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42
artemis-commons/src/main/java/org/apache/activemq/artemis/utils/collections/ConcurrentAppendOnlyChunkedList.java
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@ -42,8 +42,6 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
private static final AtomicLongFieldUpdater<ConcurrentAppendOnlyChunkedList> LAST_INDEX_UPDATER = AtomicLongFieldUpdater.newUpdater(ConcurrentAppendOnlyChunkedList.class, "lastIndex");
private static final AtomicLongFieldUpdater<ConcurrentAppendOnlyChunkedList> CACHED_LAST_INDEX_UPDATER = AtomicLongFieldUpdater.newUpdater(ConcurrentAppendOnlyChunkedList.class, "cachedLastIndex");
private final int chunkSize;
private final int chunkMask;
@ -58,10 +56,6 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
//it's using a parity bit to mark the rotation state ie size === lastIndex >> 1
private volatile long lastIndex = 0;
//cached view of lastIndex used to avoid invalidating lastIndex while being updated by the appends
private volatile long cachedLastIndex = 0;
/**
* @throws IllegalArgumentException if {@code chunkSize} is &lt;0 or not a power of 2
*/
@ -105,17 +99,11 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
if (index < 0) {
return null;
}
//it allow to perform less cache invalidations vs lastIndex if there are bursts of appends
long lastIndex = cachedLastIndex;
if (index >= lastIndex) {
lastIndex = getValidLastIndex();
final long lastIndex = getValidLastIndex();
//it is a element over the current size?
if (index >= lastIndex) {
return null;
}
//publish it for others readers
CACHED_LAST_INDEX_UPDATER.lazySet(this, lastIndex);
}
final AtomicChunk<T> buffer;
final int offset;
if (index >= chunkSize) {
@ -139,20 +127,20 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
final int chunkIndex = index >> chunkSizeLog2;
//size is never allowed to be > Integer.MAX_VALUE
final int lastChunkIndex = (int) lastIndex >> chunkSizeLog2;
int chunkIndexes = chunkIndex;
int distance = chunkIndex;
AtomicChunk<T> buffer = null;
boolean forward = true;
int distanceFromLastChunkIndex = lastChunkIndex - chunkIndex;
int distanceFromLast = lastChunkIndex - chunkIndex;
//it's worth to go backward from lastChunkIndex?
//trying first to check against the value we already have: if it won't worth, won't make sense to load the lastBuffer
if (distanceFromLastChunkIndex < chunkIndex) {
if (distanceFromLast < distance) {
final AtomicChunk<T> lastBuffer = this.lastBuffer;
//lastBuffer is a potential moving, always increasing, target ie better to re-check the distance
distanceFromLastChunkIndex = lastBuffer.index - chunkIndex;
if (distanceFromLastChunkIndex < chunkIndex) {
distanceFromLast = lastBuffer.index - chunkIndex;
if (distanceFromLast < distance) {
//we're saving some jumps ie is fine to go backward from here
buffer = lastBuffer;
chunkIndexes = distanceFromLastChunkIndex;
distance = distanceFromLast;
forward = false;
}
}
@ -160,7 +148,7 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
if (buffer == null) {
buffer = firstBuffer;
}
for (int i = 0; i < chunkIndexes; i++) {
for (int i = 0; i < distance; i++) {
//next chunk is always set if below a read lastIndex value
//previous chunk is final and can be safely read
buffer = forward ? buffer.next : buffer.prev;
@ -234,21 +222,31 @@ public final class ConcurrentAppendOnlyChunkedList<T> {
return true;
}
public T[] toArray(IntFunction<T[]> arrayAllocator) {
return toArray(arrayAllocator, 0);
}
/**
* Returns an array containing all of the elements in this collection in proper
* sequence (from first to last element).<br>
* {@code arrayAllocator} will be used to instantiate the array of the correct size with the right runtime type.
*/
public T[] toArray(IntFunction<T[]> arrayAllocator) {
public T[] toArray(IntFunction<T[]> arrayAllocator, int startIndex) {
if (startIndex < 0) {
throw new ArrayIndexOutOfBoundsException("startIndex must be >= 0");
}
final long lastIndex = getValidLastIndex();
assert lastIndex <= Integer.MAX_VALUE;
final int size = (int) lastIndex;
final T[] elements = arrayAllocator.apply(size);
if (startIndex + size > elements.length) {
throw new ArrayIndexOutOfBoundsException();
}
//fast division by a power of 2
final int chunkSize = this.chunkSize;
final int chunks = size > chunkSize ? size >> chunkSizeLog2 : 0;
AtomicChunk<T> buffer = firstBuffer;
int elementIndex = 0;
int elementIndex = startIndex;
for (int i = 0; i < chunks; i++) {
drain(buffer, elements, elementIndex, chunkSize);
elementIndex += chunkSize;

53
artemis-commons/src/test/java/org/apache/activemq/artemis/utils/collections/ConcurrentAppendOnlyChunkedListTest.java
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@ -20,13 +20,15 @@
*/
package org.apache.activemq.artemis.utils.collections;
import java.util.Arrays;
import org.junit.Assert;
import org.junit.Test;
public class ConcurrentAppendOnlyChunkedListTest {
private static final int CHUNK_SIZE = 32;
private static final int ELEMENTS = (CHUNK_SIZE * 3) + 1;
private static final int CHUNK_SIZE = 16;
private static final int ELEMENTS = (CHUNK_SIZE * 4) + 1;
private final ConcurrentAppendOnlyChunkedList<Integer> chunkedList;
@ -101,7 +103,12 @@ public class ConcurrentAppendOnlyChunkedListTest {
for (int i = 0; i < messages; i++) {
cachedElements[i] = chunkedList.get(i);
}
Assert.assertArrayEquals(cachedElements, elements);
Assert.assertArrayEquals(elements, cachedElements);
Arrays.fill(cachedElements, null);
for (int i = messages - 1; i >= 0; i--) {
cachedElements[i] = chunkedList.get(i);
}
Assert.assertArrayEquals(elements, cachedElements);
}
@Test
@ -117,7 +124,7 @@ public class ConcurrentAppendOnlyChunkedListTest {
for (int i = 0; i < messages; i++) {
cachedElements[i] = chunkedList.get(i);
}
Assert.assertArrayEquals(cachedElements, elements);
Assert.assertArrayEquals(elements, cachedElements);
}
@Test
@ -133,6 +140,44 @@ public class ConcurrentAppendOnlyChunkedListTest {
Assert.assertArrayEquals(elements, cachedElements);
}
@Test
public void shouldToArrayWithIndexReturnElementsAccordingToAddOrder() {
final int messages = ELEMENTS;
final Integer[] elements = new Integer[messages];
for (int i = 0; i < messages; i++) {
final Integer element = i;
elements[i] = element;
chunkedList.add(element);
}
final int offset = 10;
final Integer[] cachedElements = chunkedList.toArray(size -> new Integer[offset + size], offset);
Assert.assertArrayEquals(elements, Arrays.copyOfRange(cachedElements, offset, cachedElements.length));
Assert.assertArrayEquals(new Integer[offset], Arrays.copyOfRange(cachedElements, 0, offset));
}
@Test(expected = ArrayIndexOutOfBoundsException.class)
public void shouldFailToArrayWithInsufficientArrayCapacity() {
final int messages = ELEMENTS;
final Integer[] elements = new Integer[messages];
for (int i = 0; i < messages; i++) {
final Integer element = i;
elements[i] = element;
chunkedList.add(element);
}
final int offset = 10;
chunkedList.toArray(size -> new Integer[offset + size - 1], offset);
}
@Test(expected = ArrayIndexOutOfBoundsException.class)
public void shouldFailToArrayWithNegativeStartIndex() {
chunkedList.toArray(Integer[]::new, -1);
}
@Test(expected = NullPointerException.class)
public void shouldFailToArrayWithNullArray() {
chunkedList.toArray(size -> null);
}
@Test
public void shouldToArrayReturnElementsAccordingToAddAllOrder() {
final int messages = ELEMENTS;

40
artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/cursor/impl/LivePageCacheImpl.java
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@ -31,7 +31,9 @@ public final class LivePageCacheImpl implements LivePageCache {
private static final int CHUNK_SIZE = 32;
private final ConcurrentAppendOnlyChunkedList<PagedMessage> messages;
private final PagedMessage[] initialMessages;
private final ConcurrentAppendOnlyChunkedList<PagedMessage> liveMessages;
private final long pageId;
@ -39,7 +41,19 @@ public final class LivePageCacheImpl implements LivePageCache {
public LivePageCacheImpl(final long pageId) {
this.pageId = pageId;
this.messages = new ConcurrentAppendOnlyChunkedList<>(CHUNK_SIZE);
this.liveMessages = new ConcurrentAppendOnlyChunkedList<>(CHUNK_SIZE);
this.initialMessages = null;
}
public LivePageCacheImpl(final long pageId, PagedMessage[] initialMessages) {
this.pageId = pageId;
this.liveMessages = new ConcurrentAppendOnlyChunkedList<>(CHUNK_SIZE);
this.initialMessages = initialMessages;
}
private int initialMessagesSize() {
final PagedMessage[] initialMessages = this.initialMessages;
return initialMessages == null ? 0 : initialMessages.length;
}
@Override
@ -49,7 +63,7 @@ public final class LivePageCacheImpl implements LivePageCache {
@Override
public int getNumberOfMessages() {
return messages.size();
return initialMessagesSize() + liveMessages.size();
}
@Override
@ -62,7 +76,16 @@ public final class LivePageCacheImpl implements LivePageCache {
@Override
public PagedMessage getMessage(PagePosition pagePosition) {
return messages.get(pagePosition.getMessageNr());
final int messageNr = pagePosition.getMessageNr();
if (messageNr < 0) {
return null;
}
final int initialOffset = initialMessagesSize();
if (messageNr < initialOffset) {
return initialMessages[messageNr];
}
final int index = messageNr - initialOffset;
return liveMessages.get(index);
}
@Override
@ -73,7 +96,7 @@ public final class LivePageCacheImpl implements LivePageCache {
@Override
public void addLiveMessage(PagedMessage message) {
message.getMessage().usageUp();
messages.add(message);
liveMessages.add(message);
}
@Override
@ -84,7 +107,12 @@ public final class LivePageCacheImpl implements LivePageCache {
@Override
public PagedMessage[] getMessages() {
return messages.toArray(PagedMessage[]::new);
final PagedMessage[] pagedMessages = liveMessages.toArray(size -> new PagedMessage[initialMessagesSize() + size], initialMessagesSize());
final PagedMessage[] initialMessages = this.initialMessages;
if (initialMessages != null) {
System.arraycopy(initialMessages, 0, pagedMessages, 0, initialMessages.length);
}
return pagedMessages;
}
@Override

11
artemis-server/src/main/java/org/apache/activemq/artemis/core/paging/impl/PagingStoreImpl.java
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@ -478,16 +478,11 @@ public class PagingStoreImpl implements PagingStore {
Page page = createPage(pageId);
page.open();
List<PagedMessage> messages = page.read(storageManager);
final List<PagedMessage> messages = page.read(storageManager);
LivePageCache pageCache = new LivePageCacheImpl(pageId);
final PagedMessage[] initialMessages = messages.toArray(new PagedMessage[messages.size()]);
for (PagedMessage msg : messages) {
pageCache.addLiveMessage(msg);
// As we add back to the live page,
// we have to discount one when we read the page
msg.getMessage().usageDown();
}
final LivePageCache pageCache = new LivePageCacheImpl(pageId, initialMessages);
page.setLiveCache(pageCache);