Method bufferAtomicIncrement

src/HBaseClient.java:1683–1714

Buffers a durable atomic increment for coalescing. This increment will be held in memory up to the amount of time allowed by #getFlushInterval in order to allow the client to coalesce increments. Increment coalescing can dramatically reduce the number of RPCs and write load on HBase

(final AtomicIncrementRequest request)

   * @since 1.4 This method works with negative increment values.
   */
  public Deferred<Long> bufferAtomicIncrement(final AtomicIncrementRequest request) {
    final long value = request.getAmount();
    if (!BufferedIncrement.Amount.checkOverflow(value)  // Value too large.
        || flush_interval == 0) {           // Client-side buffer disabled.
      return atomicIncrement(request);
    }

    final BufferedIncrement incr =
      new BufferedIncrement(request.table(), request.key(), request.family(),
                            request.qualifier());

    do {
      BufferedIncrement.Amount amount;
      // Semi-evil: the very first time we get here, `increment_buffer' will
      // still be null (we don't initialize it in our constructor) so we catch
      // the NPE that ensues to allocate the buffer and kick off a timer to
      // regularly flush it.
      try {
        amount = increment_buffer.getUnchecked(incr);
      } catch (NullPointerException e) {
        setupIncrementCoalescing();
        amount = increment_buffer.getUnchecked(incr);
      }
      if (amount.update(value)) {
        final Deferred<Long> deferred = new Deferred<Long>();
        amount.deferred.chain(deferred);
        return deferred;
      }
      // else: Loop again to retry.
      increment_buffer.refresh(incr);
    } while (true);
  }

  /**
   * Buffers a durable atomic increment for coalescing.