package org.infinispan.statetransfer;
import static org.infinispan.commons.util.Util.toStr;
import java.util.Iterator;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import org.infinispan.container.DataContainer;
import org.infinispan.container.entries.CacheEntry;
import org.infinispan.context.Flag;
import org.infinispan.factories.annotations.Inject;
import org.infinispan.metadata.Metadata;
import org.infinispan.util.logging.Log;
import org.infinispan.util.logging.LogFactory;
/**
* Keeps track of the keys updated by normal operation and state transfer. Since the command processing happens
* concurrently with the state transfer, it needs to keep track of the keys updated by normal command in order to reject
* the updates from the state transfer. It assumes that the keys from normal operations are most recent thant the ones
* received by state transfer.
*
* @author Pedro Ruivo
* @since 7.0
*/
public class CommitManager {
private static final Log log = LogFactory.getLog(CommitManager.class);
private static final boolean trace = log.isTraceEnabled();
private final ConcurrentMap<Object, DiscardPolicy> tracker = new ConcurrentHashMap<>();
private DataContainer dataContainer;
private volatile boolean trackStateTransfer;
private volatile boolean trackXSiteStateTransfer;
@Inject
public final void inject(DataContainer dataContainer) {
this.dataContainer = dataContainer;
}
/**
* It starts tracking keys committed. All the keys committed will be flagged with this flag. State transfer received
* after the key is tracked will be discarded.
*
* @param track Flag to start tracking keys for local site state transfer or for remote site state transfer.
*/
public final void startTrack(Flag track) {
setTrack(track, true);
}
/**
* It stops tracking keys committed.
*
* @param track Flag to stop tracking keys for local site state transfer or for remote site state transfer.
*/
public final void stopTrack(Flag track) {
setTrack(track, false);
if (!trackStateTransfer && !trackXSiteStateTransfer) {
if (trace) {
log.tracef("Tracking is disabled. Clear tracker: %s", tracker);
}
tracker.clear();
} else {
for (Iterator<Map.Entry<Object, DiscardPolicy>> iterator = tracker.entrySet().iterator();
iterator.hasNext(); ) {
if (iterator.next().getValue().update(trackStateTransfer, trackXSiteStateTransfer)) {
iterator.remove();
}
}
}
}
/**
* It tries to commit the cache entry. The entry is not committed if it is originated from state transfer and other
* operation already has updated it.
*
* @param entry the entry to commit
* @param metadata the entry's metadata
* @param operation if {@code null}, it identifies this commit as originated from a normal operation. Otherwise, it
* is originated from a state transfer (local or remote site)
*/
public final void commit(final CacheEntry entry, final Metadata metadata, final Flag operation,
boolean l1Invalidation) {
if (trace) {
log.tracef("Trying to commit. Key=%s. Operation Flag=%s, L1 invalidation=%s", toStr(entry.getKey()),
operation, l1Invalidation);
}
if (l1Invalidation || (operation == null && !trackStateTransfer && !trackXSiteStateTransfer)) {
//track == null means that it is a normal put and the tracking is not enabled!
//if it is a L1 invalidation, commit without track it.
if (trace) {
log.tracef("Committing key=%s. It is a L1 invalidation or a normal put and no tracking is enabled!",
toStr(entry.getKey()));
}
entry.commit(dataContainer, metadata);
return;
}
if (isTrackDisabled(operation)) {
//this a put for state transfer but we are not tracking it. This means that the state transfer has ended
//or canceled due to a clear command.
if (trace) {
log.tracef("Not committing key=%s. It is a state transfer key but no track is enabled!",
toStr(entry.getKey()));
}
return;
}
tracker.compute(entry.getKey(), (o, discardPolicy) -> {
if (discardPolicy != null && discardPolicy.ignore(operation)) {
if (trace) {
log.tracef("Not committing key=%s. It was already overwritten! Discard policy=%s",
toStr(entry.getKey()), discardPolicy);
}
return discardPolicy;
}
entry.commit(dataContainer, metadata);
DiscardPolicy newDiscardPolicy = calculateDiscardPolicy();
if (trace) {
log.tracef("Committed key=%s. Old discard policy=%s. New discard policy=%s", toStr(entry.getKey()),
discardPolicy, newDiscardPolicy);
}
return newDiscardPolicy;
});
}
/**
* @return {@code true} if the flag is being tracked, {@code false} otherwise.
*/
public final boolean isTracking(Flag trackFlag) {
switch (trackFlag) {
case PUT_FOR_STATE_TRANSFER:
return trackStateTransfer;
case PUT_FOR_X_SITE_STATE_TRANSFER:
return trackXSiteStateTransfer;
}
return false;
}
/**
* @return {@code true} if no keys are tracked, {@code false} otherwise.
*/
public final boolean isEmpty() {
return tracker.isEmpty();
}
@Override
public String toString() {
return "CommitManager{" +
"tracker=" + tracker.size() + " key(s)" +
", trackStateTransfer=" + trackStateTransfer +
", trackXSiteStateTransfer=" + trackXSiteStateTransfer +
'}';
}
private void setTrack(Flag track, boolean value) {
if (trace) {
log.tracef("Set track to %s = %s", track, value);
}
switch (track) {
case PUT_FOR_STATE_TRANSFER:
this.trackStateTransfer = value;
break;
case PUT_FOR_X_SITE_STATE_TRANSFER:
this.trackXSiteStateTransfer = value;
break;
}
}
private boolean isTrackDisabled(Flag track) {
return (track == Flag.PUT_FOR_STATE_TRANSFER && !trackStateTransfer) ||
(track == Flag.PUT_FOR_X_SITE_STATE_TRANSFER && !trackXSiteStateTransfer);
}
private DiscardPolicy calculateDiscardPolicy() {
if (!trackXSiteStateTransfer && !trackStateTransfer) {
return null;
}
return new DiscardPolicy(trackStateTransfer, trackXSiteStateTransfer);
}
private static class DiscardPolicy {
private boolean discardST;
private boolean discardXSiteST;
private DiscardPolicy(boolean discardST, boolean discardXSiteST) {
this.discardST = discardST;
this.discardXSiteST = discardXSiteST;
}
public synchronized final boolean ignore(Flag operation) {
return (discardST && operation == Flag.PUT_FOR_STATE_TRANSFER) ||
(discardXSiteST && operation == Flag.PUT_FOR_X_SITE_STATE_TRANSFER);
}
public synchronized boolean update(boolean discardST, boolean discardXSiteST) {
this.discardST = discardST;
this.discardXSiteST = discardXSiteST;
return !this.discardST && !this.discardXSiteST;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
DiscardPolicy that = (DiscardPolicy) o;
return discardST == that.discardST && discardXSiteST == that.discardXSiteST;
}
@Override
public int hashCode() {
int result = (discardST ? 1 : 0);
result = 31 * result + (discardXSiteST ? 1 : 0);
return result;
}
@Override
public String toString() {
return "DiscardPolicy{" +
"discardStateTransfer=" + discardST +
", discardXSiteStateTransfer=" + discardXSiteST +
'}';
}
}
}