@Override
public SyncedFlushResult syncFlush(String syncId, CommitId expectedCommitId)
throws EngineException {
// best effort attempt before we acquire locks
ensureOpen();
if (indexWriter.hasUncommittedChanges()) {
logger.trace("can't sync commit [{}]. have pending changes", syncId);
return SyncedFlushResult.PENDING_OPERATIONS;
}
if (expectedCommitId.idsEqual(lastCommittedSegmentInfos.getId()) == false) {
logger.trace("can't sync commit [{}]. current commit id is not equal to expected.", syncId);
return SyncedFlushResult.COMMIT_MISMATCH;
}
try (ReleasableLock lock = writeLock.acquire()) {
ensureOpen();
ensureCanFlush();
if (indexWriter.hasUncommittedChanges()) {
logger.trace("can't sync commit [{}]. have pending changes", syncId);
return SyncedFlushResult.PENDING_OPERATIONS;
}
if (expectedCommitId.idsEqual(lastCommittedSegmentInfos.getId()) == false) {
logger.trace("can't sync commit [{}]. current commit id is not equal to expected.", syncId);
return SyncedFlushResult.COMMIT_MISMATCH;
}
logger.trace("starting sync commit [{}]", syncId);
commitIndexWriter(indexWriter, translog, syncId);
logger.debug("successfully sync committed. sync id [{}].", syncId);
lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
return SyncedFlushResult.SUCCESS;
} catch (IOException ex) {
maybeFailEngine("sync commit", ex);
throw new EngineException(shardId, "failed to sync commit", ex);
}
}
final boolean tryRenewSyncCommit() {
boolean renewed = false;
try (ReleasableLock lock = writeLock.acquire()) {
ensureOpen();
ensureCanFlush();
String syncId = lastCommittedSegmentInfos.getUserData().get(SYNC_COMMIT_ID);
if (syncId != null
&& translog.totalOperations() == 0
&& indexWriter.hasUncommittedChanges()) {
logger.trace("start renewing sync commit [{}]", syncId);
commitIndexWriter(indexWriter, translog, syncId);
logger.debug("successfully sync committed. sync id [{}].", syncId);
lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
renewed = true;
}
} catch (IOException ex) {
maybeFailEngine("renew sync commit", ex);
throw new EngineException(shardId, "failed to renew sync commit", ex);
}
if (renewed) { // refresh outside of the write lock
refresh("renew sync commit");
}
return renewed;
}
@Override
public CommitId flush(boolean force, boolean waitIfOngoing) throws EngineException {
ensureOpen();
final byte[] newCommitId;
/*
* Unfortunately the lock order is important here. We have to acquire the readlock first otherwise
* if we are flushing at the end of the recovery while holding the write lock we can deadlock if:
* Thread 1: flushes via API and gets the flush lock but blocks on the readlock since Thread 2 has the writeLock
* Thread 2: flushes at the end of the recovery holding the writeLock and blocks on the flushLock owned by Thread 1
*/
try (ReleasableLock lock = readLock.acquire()) {
ensureOpen();
if (flushLock.tryLock() == false) {
// if we can't get the lock right away we block if needed otherwise barf
if (waitIfOngoing) {
logger.trace("waiting for in-flight flush to finish");
flushLock.lock();
logger.trace("acquired flush lock after blocking");
} else {
throw new FlushNotAllowedEngineException(shardId, "already flushing...");
}
} else {
logger.trace("acquired flush lock immediately");
}
try {
if (indexWriter.hasUncommittedChanges() || force) {
ensureCanFlush();
try {
translog.prepareCommit();
logger.trace("starting commit for flush; commitTranslog=true");
commitIndexWriter(indexWriter, translog, null);
logger.trace("finished commit for flush");
// we need to refresh in order to clear older version values
refresh("version_table_flush");
// after refresh documents can be retrieved from the index so we can now commit the
// translog
translog.commit();
} catch (Throwable e) {
throw new FlushFailedEngineException(shardId, e);
}
}
/*
* we have to inc-ref the store here since if the engine is closed by a tragic event
* we don't acquire the write lock and wait until we have exclusive access. This might also
* dec the store reference which can essentially close the store and unless we can inc the reference
* we can't use it.
*/
store.incRef();
try {
// reread the last committed segment infos
lastCommittedSegmentInfos = store.readLastCommittedSegmentsInfo();
} catch (Throwable e) {
if (isClosed.get() == false) {
logger.warn("failed to read latest segment infos on flush", e);
if (Lucene.isCorruptionException(e)) {
throw new FlushFailedEngineException(shardId, e);
}
}
} finally {
store.decRef();
}
newCommitId = lastCommittedSegmentInfos.getId();
} catch (FlushFailedEngineException ex) {
maybeFailEngine("flush", ex);
throw ex;
} finally {
flushLock.unlock();
}
}
// We don't have to do this here; we do it defensively to make sure that even if wall clock time
// is misbehaving
// (e.g., moves backwards) we will at least still sometimes prune deleted tombstones:
if (engineConfig.isEnableGcDeletes()) {
pruneDeletedTombstones();
}
return new CommitId(newCommitId);
}