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提交 9cc5ebee authored 作者: Andrei Tokar's avatar Andrei Tokar
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Refactor code around append buffer locking

上级 5de4e30b
隐藏空白字符变更
内嵌 并排
正在显示 包含 66 行增加 和 123 行删除
h2/src/main/org/h2/mvstore/MVMap.java
浏览文件 @ 9cc5ebee
......@@ -427,7 +427,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
Page emptyRootPage = createEmptyLeaf();
int attempt = 0;
do {
rootReference = getRootInternal();
rootReference = getRoot();
} while (!updateRoot(rootReference, emptyRootPage, ++attempt));
rootReference.root.removeAllRecursive();
}
......@@ -778,25 +778,21 @@ public class MVMap<K, V> extends AbstractMap<K, V>
* @return the root page
*/
public final Page getRootPage() {
return getRoot().root;
return flushAndGetRoot().root;
}
public final RootReference getRoot() {
return flushAndGetRoot();
public RootReference getRoot() {
return root.get();
}
private RootReference flushAndGetRoot() {
RootReference rootReference = getRootInternal();
public RootReference flushAndGetRoot() {
RootReference rootReference = getRoot();
if (singleWriter && rootReference.getAppendCounter() > 0) {
return flushAppendBuffer(rootReference, false);
}
return rootReference;
}
private RootReference getRootInternal() {
return root.get();
}
final void setRoot(Page rootPage) {
int attempt = 0;
while (setNewRoot(null, rootPage, ++attempt, false) == null) {/**/}
......@@ -819,7 +815,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
*/
private RootReference setNewRoot(RootReference oldRoot, Page newRootPage,
int attemptUpdateCounter, boolean obeyLock) {
RootReference currentRoot = getRoot();
RootReference currentRoot = flushAndGetRoot();
assert newRootPage != null || currentRoot != null;
if (currentRoot != oldRoot && oldRoot != null) {
return null;
......@@ -863,7 +859,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
void rollbackRoot(long version)
{
RootReference rootReference = getRoot();
RootReference rootReference = flushAndGetRoot();
RootReference previous;
while (rootReference.version >= version && (previous = rootReference.previous) != null) {
if (root.compareAndSet(rootReference, previous)) {
......@@ -977,13 +973,13 @@ public class MVMap<K, V> extends AbstractMap<K, V>
* @return the number of entries
*/
public final long sizeAsLong() {
RootReference rootReference = getRootInternal();
RootReference rootReference = getRoot();
return rootReference.root.getTotalCount() + rootReference.getAppendCounter();
}
@Override
public boolean isEmpty() {
RootReference rootReference = getRootInternal();
RootReference rootReference = getRoot();
Page rootPage = rootReference.root;
return rootPage.isLeaf() && rootPage.getKeyCount() == 0 && rootReference.getAppendCounter() == 0;
}
......@@ -1072,7 +1068,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
final boolean hasChangesSince(long version) {
RootReference rootReference = getRoot();
Page root = rootReference.root;
return !root.isSaved() && root.getTotalCount() > 0 ||
return !root.isSaved() && rootReference.getTotalCount() > 0 ||
getVersion(rootReference) > version;
}
......@@ -1125,7 +1121,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
final RootReference setWriteVersion(long writeVersion) {
int attempt = 0;
while(true) {
RootReference rootReference = getRoot();
RootReference rootReference = flushAndGetRoot();
if(rootReference.version >= writeVersion) {
return rootReference;
} else if (isClosed()) {
......@@ -1213,7 +1209,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
while ((keyCount = rootReference.getAppendCounter()) > 0) {
if (lockedRootReference == null) {
lockedRootReference = tryLock(rootReference, ++attempt);
rootReference = lockedRootReference == null ? getRootInternal() : lockedRootReference;
rootReference = lockedRootReference == null ? getRoot() : lockedRootReference;
continue;
}
......@@ -1308,12 +1304,11 @@ public class MVMap<K, V> extends AbstractMap<K, V>
assert lockedForUpdate || updatedRootReference.getAppendCounter() == 0;
return updatedRootReference;
}
rootReference = getRootInternal();
rootReference = getRoot();
}
} finally {
if (lockedRootReference != null && !lockedForUpdate) {
assert rootReference.root == lockedRootReference.root;
// assert rootReference.appendCounter == lockedRootReference.appendCounter : rootReference.appendCounter + " != " + lockedRootReference.appendCounter;
rootReference = unlockRoot(lockedRootReference.root, lockedRootReference.appendCounter);
}
}
......@@ -1342,29 +1337,20 @@ public class MVMap<K, V> extends AbstractMap<K, V>
* @param value to be appended
*/
public void append(K key, V value) {
int attempt = 0;
RootReference lockedRootReference = null;
boolean success;
do {
RootReference rootReference = getRootInternal();
if (lockedRootReference == null) {
lockedRootReference = lockRoot(rootReference, ++attempt);
rootReference = lockedRootReference;
}
int appendCounter = rootReference.getAppendCounter();
RootReference rootReference = lockRoot(getRoot(), 1);
int appendCounter = rootReference.getAppendCounter();
try {
if (appendCounter >= keysPerPage) {
// beforeWrite();
rootReference = flushAppendBuffer(rootReference, true);
appendCounter = rootReference.getAppendCounter();
assert appendCounter < keysPerPage;
}
keysBuffer[appendCounter] = key;
valuesBuffer[appendCounter] = value;
RootReference updatedRootReference = new RootReference(rootReference, appendCounter + 1, ++attempt, false);
success = root.compareAndSet(rootReference, updatedRootReference);
} while(!success);
++appendCounter;
} finally {
unlockRoot(rootReference.root, appendCounter);
}
}
/**
......@@ -1373,34 +1359,24 @@ public class MVMap<K, V> extends AbstractMap<K, V>
* Non-updating method may be used concurrently, but latest removal may not be visible.
*/
public void trimLast() {
int attempt = 0;
RootReference lockedRootReference = null;
RootReference rootReference = getRootInternal();
boolean success = false;
while(!success) {
int appendCounter = rootReference.getAppendCounter();
if (appendCounter > 0) {
if (lockedRootReference == null) {
lockedRootReference = lockRoot(rootReference, ++attempt);
rootReference = lockedRootReference;
continue;
}
// RootReference updatedRootReference = new RootReference(rootReference, appendCounter - 1, ++attempt, rootReference.lockedForUpdate);
RootReference updatedRootReference = new RootReference(rootReference, appendCounter - 1, ++attempt, false);
success = root.compareAndSet(rootReference, updatedRootReference);
rootReference = getRootInternal();
} else {
if (lockedRootReference != null) {
rootReference = unlockRoot(lockedRootReference.root, lockedRootReference.appendCounter);
}
assert rootReference.root.getKeyCount() > 0;
Page lastLeaf = rootReference.root.getAppendCursorPos(null).page;
assert lastLeaf.isLeaf();
assert lastLeaf.getKeyCount() > 0;
Object key = lastLeaf.getKey(lastLeaf.getKeyCount() - 1);
success = remove(key) != null;
assert success;
RootReference rootReference = getRoot();
int appendCounter = rootReference.getAppendCounter();
boolean fallback = appendCounter == 0;
if (!fallback) {
rootReference = lockRoot(rootReference, 1);
appendCounter = rootReference.getAppendCounter();
fallback = appendCounter == 0;
if (!fallback) {
--appendCounter;
}
unlockRoot(rootReference.root, appendCounter);
}
if (fallback) {
Page lastLeaf = rootReference.root.getAppendCursorPos(null).page;
assert lastLeaf.isLeaf();
assert lastLeaf.getKeyCount() > 0;
Object key = lastLeaf.getKey(lastLeaf.getKeyCount() - 1);
remove(key);
}
}
......@@ -1462,16 +1438,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
}
// This one is used for unlocking
RootReference(RootReference r, Page root, int appendCounter) {
this.root = root;
this.version = r.version;
this.previous = r.previous;
this.updateCounter = r.updateCounter;
this.updateAttemptCounter = r.updateAttemptCounter;
this.lockedForUpdate = false;
this.appendCounter = (byte)appendCounter;
}
RootReference(RootReference r, Page root, int appendCounter, boolean lockedForUpdate) {
this.root = root;
this.version = r.version;
......@@ -1509,21 +1475,14 @@ public class MVMap<K, V> extends AbstractMap<K, V>
this.appendCounter = 0;
}
// This one is used for append buffer maintenance
RootReference(RootReference r, int appendCounter, int attempt, boolean lockedForUpdate) {
this.root = r.root;
this.version = r.version;
this.previous = r.previous;
this.updateCounter = r.updateCounter + 1;
this.updateAttemptCounter = r.updateAttemptCounter + attempt;
this.lockedForUpdate = lockedForUpdate;
this.appendCounter = (byte)appendCounter;
}
public int getAppendCounter() {
return appendCounter & 0xff;
}
public long getTotalCount() {
return root.getTotalCount() + getAppendCounter();
}
@Override
public String toString() {
return "RootReference("+ System.identityHashCode(root)+","+version+","+ lockedForUpdate +")";
......@@ -1794,21 +1753,8 @@ public class MVMap<K, V> extends AbstractMap<K, V>
beforeWrite();
IntValueHolder unsavedMemoryHolder = new IntValueHolder();
int attempt = 0;
// RootReference oldRootReference = null;
while(true) {
RootReference rootReference = getRoot();
// int contention = 1;
// if (oldRootReference != null) {
// long updateAttemptCounter = rootReference.updateAttemptCounter -
// oldRootReference.updateAttemptCounter;
// assert updateAttemptCounter >= 0 : updateAttemptCounter;
// long updateCounter = rootReference.updateCounter - oldRootReference.updateCounter;
// assert updateCounter >= 0 : updateCounter;
// assert updateAttemptCounter >= updateCounter : updateAttemptCounter + " >= " + updateCounter;
// contention = (int)((updateAttemptCounter+1) / (updateCounter+1));
// }
// oldRootReference = rootReference;
RootReference rootReference = flushAndGetRoot();
RootReference lockedRootReference = null;
if ((++attempt > 3 || rootReference.lockedForUpdate)) {
lockedRootReference = lockRoot(rootReference, attempt);
......@@ -1901,17 +1847,6 @@ public class MVMap<K, V> extends AbstractMap<K, V>
}
}
p = replacePage(pos, p, unsavedMemoryHolder);
/*
unsavedMemory += p.getMemory();
while (pos != null) {
Page c = p;
p = pos.page;
p = p.copy();
p.setChild(pos.index, c);
unsavedMemory += p.getMemory();
pos = pos.parent;
}
*/
rootPage = p;
if(lockedRootReference == null && !updateRoot(rootReference, p, attempt)) {
decisionMaker.reset();
......@@ -1939,7 +1874,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
if (lockedRootReference != null) {
return lockedRootReference;
}
rootReference = getRootInternal();
rootReference = getRoot();
}
}
......@@ -1966,7 +1901,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
if(attempt > 4) {
if (attempt <= 12) {
Thread.yield();
} else if (attempt <= 64) {
} else if (attempt <= 24) {
try {
Thread.sleep(0, 10 * contention + 5);
} catch (InterruptedException ex) {
......@@ -1976,7 +1911,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
synchronized (lock) {
notificationRequested = true;
try {
lock.wait(0, 100);
lock.wait(100);
} catch (InterruptedException ignore) {
}
}
......@@ -1989,14 +1924,12 @@ public class MVMap<K, V> extends AbstractMap<K, V>
RootReference updatedRootReference;
boolean success;
do {
RootReference rootReference = getRootInternal();
// assert rootReference.lockedForUpdate;
if (!rootReference.lockedForUpdate) {
return rootReference;
}
updatedRootReference = new RootReference(rootReference, newRoot, appendCounter);
RootReference rootReference = getRoot();
assert rootReference.lockedForUpdate;
updatedRootReference = new RootReference(rootReference, newRoot, appendCounter, false);
success = root.compareAndSet(rootReference, updatedRootReference);
} while(!success);
if (notificationRequested) {
synchronized (lock) {
notificationRequested = false;
......
h2/src/main/org/h2/mvstore/MVStore.java
浏览文件 @ 9cc5ebee
......@@ -1400,7 +1400,7 @@ public class MVStore implements AutoCloseable {
try {
ChunkIdsCollector collector = new ChunkIdsCollector(meta.getId());
long oldestVersionToKeep = getOldestVersionToKeep();
MVMap.RootReference rootReference = meta.getRoot();
MVMap.RootReference rootReference = meta.flushAndGetRoot();
if (fast) {
MVMap.RootReference previous;
while (rootReference.version >= oldestVersionToKeep && (previous = rootReference.previous) != null) {
......
h2/src/main/org/h2/mvstore/rtree/MVRTreeMap.java
浏览文件 @ 9cc5ebee
......@@ -134,7 +134,7 @@ public final class MVRTreeMap<V> extends MVMap<SpatialKey, V> {
int attempt = 0;
while(true) {
++attempt;
RootReference rootReference = getRoot();
RootReference rootReference = flushAndGetRoot();
Page p = rootReference.root.copy(true);
V result = operate(p, key, value, decisionMaker);
if (!p.isLeaf() && p.getTotalCount() == 0) {
......
h2/src/main/org/h2/mvstore/tx/TransactionMap.java
浏览文件 @ 9cc5ebee
......@@ -104,7 +104,7 @@ public class TransactionMap<K, V> extends AbstractMap<K, V> {
long undoLogSize;
do {
committingTransactions = store.committingTransactions.get();
mapRootReference = map.getRoot();
mapRootReference = map.flushAndGetRoot();
BitSet opentransactions = store.openTransactions.get();
undoLogRootReferences = new MVMap.RootReference[opentransactions.length()];
undoLogSize = 0;
......@@ -113,7 +113,7 @@ public class TransactionMap<K, V> extends AbstractMap<K, V> {
if (undoLog != null) {
MVMap.RootReference rootReference = undoLog.getRoot();
undoLogRootReferences[i] = rootReference;
undoLogSize += rootReference.root.getTotalCount() + rootReference.getAppendCounter();
undoLogSize += rootReference.getTotalCount();
}
}
} while(committingTransactions != store.committingTransactions.get() ||
......@@ -124,7 +124,7 @@ public class TransactionMap<K, V> extends AbstractMap<K, V> {
// should be considered as committed.
// Subsequent processing uses this snapshot info only.
Page mapRootPage = mapRootReference.root;
long size = mapRootPage.getTotalCount();
long size = mapRootReference.getTotalCount();
// if we are looking at the map without any uncommitted values
if (undoLogSize == 0) {
return size;
......@@ -240,6 +240,16 @@ public class TransactionMap<K, V> extends AbstractMap<K, V> {
return set(key, decisionMaker);
}
/**
* Appends entry to uderlying map. This method may be used concurrently,
* but latest appended values are not guaranteed to be visible.
* @param key should be higher in map's order than any existing key
* @param value to be appended
*/
public void append(K key, V value) {
map.append(key, VersionedValue.getInstance(transaction.log(map.getId(), key, null), value, null));
}
/**
* Lock row for the given key.
* <p>
......@@ -678,7 +688,7 @@ public class TransactionMap<K, V> extends AbstractMap<K, V> {
MVMap.RootReference mapRootReference;
do {
committingTransactions = store.committingTransactions.get();
mapRootReference = map.getRoot();
mapRootReference = map.flushAndGetRoot();
} while (committingTransactions != store.committingTransactions.get());
// Now we have a snapshot, where mapRootReference points to state of the map
// and committingTransactions mask tells us which of seemingly uncommitted changes
......
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