public long getApproximateSizes(Range range) {
Version v = versions.getCurrent();
InternalKey startKey =
new InternalKey(
Slices.wrappedBuffer(range.start()),
SequenceNumber.MAX_SEQUENCE_NUMBER,
ValueType.VALUE);
InternalKey limitKey =
new InternalKey(
Slices.wrappedBuffer(range.limit()),
SequenceNumber.MAX_SEQUENCE_NUMBER,
ValueType.VALUE);
long startOffset = v.getApproximateOffsetOf(startKey);
long limitOffset = v.getApproximateOffsetOf(limitKey);
return (limitOffset >= startOffset ? limitOffset - startOffset : 0);
}
@Override
public byte[] get(byte[] key, ReadOptions options) throws DBException {
checkBackgroundException();
LookupKey lookupKey;
mutex.lock();
try {
SnapshotImpl snapshot = getSnapshot(options);
lookupKey = new LookupKey(Slices.wrappedBuffer(key), snapshot.getLastSequence());
// First look in the memtable, then in the immutable memtable (if any).
LookupResult lookupResult = memTable.get(lookupKey);
if (lookupResult != null) {
Slice value = lookupResult.getValue();
if (value == null) {
return null;
}
return value.getBytes();
}
if (immutableMemTable != null) {
lookupResult = immutableMemTable.get(lookupKey);
if (lookupResult != null) {
Slice value = lookupResult.getValue();
if (value == null) {
return null;
}
return value.getBytes();
}
}
} finally {
mutex.unlock();
}
// Not in memTables; try live files in level order
LookupResult lookupResult = versions.get(lookupKey);
// schedule compaction if necessary
mutex.lock();
try {
if (versions.needsCompaction()) {
maybeScheduleCompaction();
}
} finally {
mutex.unlock();
}
if (lookupResult != null) {
Slice value = lookupResult.getValue();
if (value != null) {
return value.getBytes();
}
}
return null;
}
private Slice writeWriteBatch(WriteBatchImpl updates, long sequenceBegin) {
Slice record = Slices.allocate(SIZE_OF_LONG + SIZE_OF_INT + updates.getApproximateSize());
final SliceOutput sliceOutput = record.output();
sliceOutput.writeLong(sequenceBegin);
sliceOutput.writeInt(updates.size());
updates.forEach(
new Handler() {
@Override
public void put(Slice key, Slice value) {
sliceOutput.writeByte(VALUE.getPersistentId());
writeLengthPrefixedBytes(sliceOutput, key);
writeLengthPrefixedBytes(sliceOutput, value);
}
@Override
public void delete(Slice key) {
sliceOutput.writeByte(DELETION.getPersistentId());
writeLengthPrefixedBytes(sliceOutput, key);
}
});
return record.slice(0, sliceOutput.size());
}
