Method getRangeStream

fdbclient/NativeAPI.actor.cpp:5539–5576

A method for streaming data from the storage server that is more efficient than getRange when reading large amounts of data

// A method for streaming data from the storage server that is more efficient than getRange when reading large amounts
// of data
Future<Void> Transaction::getRangeStream(const PromiseStream<RangeResult>& results,
                                         const KeySelector& begin,
                                         const KeySelector& end,
                                         GetRangeLimits limits,
                                         Snapshot snapshot,
                                         Reverse reverse) {
	++trState->cx->transactionLogicalReads;
	++trState->cx->transactionGetRangeStreamRequests;

	// FIXME: limits are not implemented yet, and this code has not be tested with reverse=true
	ASSERT(!limits.hasByteLimit() && !limits.hasRowLimit() && !reverse);

	KeySelector b = begin;
	if (b.orEqual) {
		CODE_PROBE(true, "Native stream begin orEqual==true");
		b.removeOrEqual(b.arena());
	}

	KeySelector e = end;
	if (e.orEqual) {
		CODE_PROBE(true, "Native stream end orEqual==true");
		e.removeOrEqual(e.arena());
	}

	if (b.offset >= e.offset && b.getKey() >= e.getKey()) {
		CODE_PROBE(true, "Native stream range inverted");
		results.sendError(end_of_stream());
		return Void();
	}

	Promise<std::pair<Key, Key>> conflictRange;
	if (!snapshot) {
		extraConflictRanges.push_back(conflictRange.getFuture());
	}

	return forwardErrors(
	    ::getRangeStream(trState, results, getReadVersion(), b, e, limits, conflictRange, snapshot, reverse), results);
}

Future<Void> Transaction::getRangeStream(const PromiseStream<RangeResult>& results,
                                         const KeySelector& begin,