Function isKeyValueInSample

fdbserver/storageserver.actor.cpp:9549–9565

Determines whether a key-value pair should be included in a byte sample Also returns size information about the sample

// Determines whether a key-value pair should be included in a byte sample
// Also returns size information about the sample
ByteSampleInfo isKeyValueInSample(KeyValueRef keyValue) {
	ByteSampleInfo info;

	const KeyRef key = keyValue.key;
	info.size = key.size() + keyValue.value.size();

	uint32_t a = 0;
	uint32_t b = 0;
	hashlittle2(key.begin(), key.size(), &a, &b);

	double probability =
	    (double)info.size / (key.size() + SERVER_KNOBS->BYTE_SAMPLING_OVERHEAD) / SERVER_KNOBS->BYTE_SAMPLING_FACTOR;
	info.inSample = a / ((1 << 30) * 4.0) < probability;
	info.sampledSize = info.size / std::min(1.0, probability);

	return info;
}

void StorageServer::addMutationToMutationLogOrStorage(Version ver, MutationRef m) {
	if (ver != invalidVersion) {