Method readRange

fdbserver/KeyValueStoreMemory.actor.cpp:235–279

If rowLimit>=0, reads first rows sorted ascending, otherwise reads last rows sorted descending The total size of the returned value (less the last entry) will be less than byteLimit

	// If rowLimit>=0, reads first rows sorted ascending, otherwise reads last rows sorted descending
	// The total size of the returned value (less the last entry) will be less than byteLimit
	Future<RangeResult> readRange(KeyRangeRef keys, int rowLimit, int byteLimit, IKeyValueStore::ReadType) override {
		if (recovering.isError())
			throw recovering.getError();
		if (!recovering.isReady())
			return waitAndReadRange(this, keys, rowLimit, byteLimit);

		RangeResult result;
		if (rowLimit == 0) {
			return result;
		}

		if (rowLimit > 0) {
			auto it = data.lower_bound(keys.begin);
			while (it != data.end() && rowLimit && byteLimit > 0) {
				StringRef tempKey = it.getKey(reserved_buffer);
				if (tempKey >= keys.end)
					break;

				byteLimit -= sizeof(KeyValueRef) + tempKey.size() + it.getValue().size();
				result.push_back_deep(result.arena(), KeyValueRef(tempKey, it.getValue()));
				++it;
				--rowLimit;
			}
		} else {
			rowLimit = -rowLimit;
			auto it = data.previous(data.lower_bound(keys.end));
			while (it != data.end() && rowLimit && byteLimit > 0) {
				StringRef tempKey = it.getKey(reserved_buffer);
				if (tempKey < keys.begin)
					break;

				byteLimit -= sizeof(KeyValueRef) + tempKey.size() + it.getValue().size();
				result.push_back_deep(result.arena(), KeyValueRef(tempKey, it.getValue()));
				it = data.previous(it);
				--rowLimit;
			}
		}

		result.more = rowLimit == 0 || byteLimit <= 0;
		if (result.more) {
			ASSERT(result.size() > 0);
			result.readThrough = result[result.size() - 1].key;
		}
		return result;
	}

	void resyncLog() override {
		ASSERT(recovering.isReady());