/**
* @param ref The ref.
* @return The offset to list record pointer; list record is created if it doesn't exist.
*/
private long createOrGetListRecord(long ref) {
if (Ref.hasList(ref)) {
// LOG.info("Found list record at " + writeBuffers.getReadPoint());
return writeBuffers.getReadPoint(); // Assumes we are here after key compare.
}
long firstTailOffset = Ref.getOffset(ref);
// LOG.info("First tail offset to create list record is " + firstTailOffset);
// Determine the length of storage for value and key lengths of the first record.
writeBuffers.setReadPoint(firstTailOffset);
writeBuffers.skipVLong();
writeBuffers.skipVLong();
int lengthsLength = (int) (writeBuffers.getReadPoint() - firstTailOffset);
// Create the list record, copy first record value/key lengths there.
writeBuffers.writeBytes(firstTailOffset, lengthsLength);
long lrPtrOffset = writeBuffers.getWritePoint();
// LOG.info("Creating list record: copying " + lengthsLength + ", lrPtrOffset " + lrPtrOffset);
// Reserve 5 bytes for writeValueRecord to fill. There might be junk there so null them.
writeBuffers.write(FIVE_ZEROES);
// Link the list record to the first element.
writeBuffers.writeFiveByteULong(firstTailOffset, lrPtrOffset - lengthsLength - firstTailOffset);
return lrPtrOffset;
}
/** Writes the debug dump of the table into logs. Not thread-safe. */
public void debugDumpTable() {
StringBuilder dump = new StringBuilder(keysAssigned + " keys\n");
TreeMap<Long, Integer> byteIntervals = new TreeMap<Long, Integer>();
int examined = 0;
for (int slot = 0; slot < refs.length; ++slot) {
long ref = refs[slot];
if (ref == 0) {
continue;
}
++examined;
long recOffset = getFirstRecordLengthsOffset(ref, null);
long tailOffset = Ref.getOffset(ref);
writeBuffers.setReadPoint(recOffset);
int valueLength = (int) writeBuffers.readVLong(), keyLength = (int) writeBuffers.readVLong();
long ptrOffset = writeBuffers.getReadPoint();
if (Ref.hasList(ref)) {
byteIntervals.put(recOffset, (int) (ptrOffset + 5 - recOffset));
}
long keyOffset = tailOffset - valueLength - keyLength;
byte[] key = new byte[keyLength];
WriteBuffers.ByteSegmentRef fakeRef = new WriteBuffers.ByteSegmentRef(keyOffset, keyLength);
byteIntervals.put(keyOffset - 4, keyLength + 4);
writeBuffers.populateValue(fakeRef);
System.arraycopy(fakeRef.getBytes(), (int) fakeRef.getOffset(), key, 0, keyLength);
dump.append(Utils.toStringBinary(key, 0, key.length))
.append(" ref [")
.append(dumpRef(ref))
.append("]: ");
Result hashMapResult = new Result();
getValueResult(key, 0, key.length, hashMapResult);
List<WriteBuffers.ByteSegmentRef> results = new ArrayList<WriteBuffers.ByteSegmentRef>();
WriteBuffers.ByteSegmentRef byteSegmentRef = hashMapResult.first();
while (byteSegmentRef != null) {
results.add(hashMapResult.byteSegmentRef);
byteSegmentRef = hashMapResult.next();
}
dump.append(results.size()).append(" rows\n");
for (int i = 0; i < results.size(); ++i) {
WriteBuffers.ByteSegmentRef segment = results.get(i);
byteIntervals.put(
segment.getOffset(),
segment.getLength() + ((i == 0) ? 1 : 0)); // state byte in the first record
}
}
if (examined != keysAssigned) {
dump.append("Found " + examined + " keys!\n");
}
// Report suspicious gaps in writeBuffers
long currentOffset = 0;
for (Map.Entry<Long, Integer> e : byteIntervals.entrySet()) {
long start = e.getKey(), len = e.getValue();
if (start - currentOffset > 4) {
dump.append("Gap! [" + currentOffset + ", " + start + ")\n");
}
currentOffset = start + len;
}
LOG.info("Hashtable dump:\n " + dump.toString());
}
/**
* Finds a key. Values can be read with the supplied result object.
*
* @param key Key buffer.
* @param offset the offset to the key in the buffer
* @param hashMapResult The object to fill in that can read the values.
* @param readPos Holds mutable read position for thread safety.
* @return The state byte.
*/
private byte getValueResult(
byte[] key, int offset, int length, Result hashMapResult, WriteBuffers.Position readPos) {
hashMapResult.forget();
// First, find first record for the key.
long ref = findKeyRefToRead(key, offset, length, readPos);
if (ref == 0) {
return 0;
}
boolean hasList = Ref.hasList(ref);
// This relies on findKeyRefToRead doing key equality check and leaving read ptr where needed.
long offsetAfterListRecordKeyLen = hasList ? writeBuffers.getReadPoint(readPos) : 0;
hashMapResult.set(this, Ref.getOffset(ref), hasList, offsetAfterListRecordKeyLen, readPos);
return Ref.getStateByte(ref);
}