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Fix bug in LockTable #95

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Fix bug in LockTable #95

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7b326e2
Change class of lockerMap to ConcurrentHashMap
koihia Apr 28, 2022
e9d8174
Fix memory leak in txWaitMap
koihia Apr 28, 2022
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199 changes: 107 additions & 92 deletions src/main/java/org/vanilladb/core/storage/tx/concurrency/LockTable.java
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Original file line number Diff line number Diff line change
Expand Up @@ -95,7 +95,7 @@ public void run() {
}
}

private Map<Object, Lockers> lockerMap = new HashMap<Object, Lockers>();
private Map<Object, Lockers> lockerMap = new ConcurrentHashMap<>();
private Map<Long, Set<Object>> lockByMap = new ConcurrentHashMap<Long, Set<Object>>();
private Set<Long> txnsToBeAborted = Collections.synchronizedSet(new HashSet<Long>());
private Map<Long, Object> txWaitMap = new ConcurrentHashMap<Long, Object>();
Expand Down Expand Up @@ -173,30 +173,33 @@ private void toBeAbortedAndNotified(long txNum) {
void sLock(Object obj, long txNum) {
Object anchor = getAnchor(obj);
txWaitMap.put(txNum, anchor);
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
try {
synchronized (anchor) {
Lockers lks = prepareLockers(obj);

if (hasSLock(lks, txNum))
return;
if (hasSLock(lks, txNum))
return;

try {
long timestamp = System.currentTimeMillis();
while (!sLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, S_LOCK);
lks.requestSet.add(txNum);
try {
long timestamp = System.currentTimeMillis();
while (!sLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, S_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!sLockable(lks, txNum))
throw new LockAbortException();
lks.sLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException("abort tx." + txNum + " by interrupted");
}
if (!sLockable(lks, txNum))
throw new LockAbortException();
lks.sLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException("abort tx." + txNum + " by interrupted");
}
} finally {
txWaitMap.remove(txNum);
}
txWaitMap.remove(txNum);
}

/**
Expand All @@ -212,30 +215,33 @@ void sLock(Object obj, long txNum) {
void xLock(Object obj, long txNum) {
Object anchor = getAnchor(obj);
txWaitMap.put(txNum, anchor);
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
try {
synchronized (anchor) {
Lockers lks = prepareLockers(obj);

if (hasXLock(lks, txNum))
return;
if (hasXLock(lks, txNum))
return;

try {
long timestamp = System.currentTimeMillis();
while (!xLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, X_LOCK);
lks.requestSet.add(txNum);
try {
long timestamp = System.currentTimeMillis();
while (!xLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, X_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!xLockable(lks, txNum))
anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!xLockable(lks, txNum))
throw new LockAbortException();
lks.xLocker = txNum;
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
lks.xLocker = txNum;
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
}
}
} finally {
txWaitMap.remove(txNum);
}
txWaitMap.remove(txNum);
}

/**
Expand All @@ -251,30 +257,33 @@ void xLock(Object obj, long txNum) {
void sixLock(Object obj, long txNum) {
Object anchor = getAnchor(obj);
txWaitMap.put(txNum, anchor);
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
try {
synchronized (anchor) {
Lockers lks = prepareLockers(obj);

if (hasSixLock(lks, txNum))
return;
if (hasSixLock(lks, txNum))
return;

try {
long timestamp = System.currentTimeMillis();
while (!sixLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, SIX_LOCK);
lks.requestSet.add(txNum);
try {
long timestamp = System.currentTimeMillis();
while (!sixLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, SIX_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!sixLockable(lks, txNum))
anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!sixLockable(lks, txNum))
throw new LockAbortException();
lks.sixLocker = txNum;
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
lks.sixLocker = txNum;
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
}
}
} finally {
txWaitMap.remove(txNum);
}
txWaitMap.remove(txNum);
}

/**
Expand All @@ -289,28 +298,31 @@ void sixLock(Object obj, long txNum) {
void isLock(Object obj, long txNum) {
Object anchor = getAnchor(obj);
txWaitMap.put(txNum, anchor);
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
if (hasIsLock(lks, txNum))
return;
try {
long timestamp = System.currentTimeMillis();
while (!isLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, IS_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!isLockable(lks, txNum))
try {
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
if (hasIsLock(lks, txNum))
return;
try {
long timestamp = System.currentTimeMillis();
while (!isLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, IS_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!isLockable(lks, txNum))
throw new LockAbortException();
lks.isLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
lks.isLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
}
}
} finally {
txWaitMap.remove(txNum);
}
txWaitMap.remove(txNum);
}

/**
Expand All @@ -325,30 +337,33 @@ void isLock(Object obj, long txNum) {
void ixLock(Object obj, long txNum) {
Object anchor = getAnchor(obj);
txWaitMap.put(txNum, anchor);
synchronized (anchor) {
Lockers lks = prepareLockers(obj);
try {
synchronized (anchor) {
Lockers lks = prepareLockers(obj);

if (hasIxLock(lks, txNum))
return;
if (hasIxLock(lks, txNum))
return;

try {
long timestamp = System.currentTimeMillis();
while (!ixLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, IX_LOCK);
lks.requestSet.add(txNum);
try {
long timestamp = System.currentTimeMillis();
while (!ixLockable(lks, txNum) && !waitingTooLong(timestamp)) {
avoidDeadlock(lks, txNum, IX_LOCK);
lks.requestSet.add(txNum);

anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!ixLockable(lks, txNum))
anchor.wait(MAX_TIME);
lks.requestSet.remove(txNum);
}
if (!ixLockable(lks, txNum))
throw new LockAbortException();
lks.ixLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
lks.ixLockers.add(txNum);
getObjectSet(txNum).add(obj);
} catch (InterruptedException e) {
throw new LockAbortException();
}
}
} finally {
txWaitMap.remove(txNum);
}
txWaitMap.remove(txNum);
}

/**
Expand Down