Method applyChanges

fdbclient/GlobalConfig.actor.cpp:42–67

GlobalConfig::GlobalConfig(DatabaseContext* cx) : cx(cx), lastUpdate(0) {}

void GlobalConfig::applyChanges(Transaction& tr,
                                const VectorRef<KeyValueRef>& insertions,
                                const VectorRef<KeyRangeRef>& clears) {
	VersionHistory vh{ 0 };
	for (const auto& kv : insertions) {
		vh.mutations.emplace_back_deep(vh.mutations.arena(), MutationRef(MutationRef::SetValue, kv.key, kv.value));
		tr.set(kv.key.withPrefix(globalConfigKeysPrefix), kv.value);
	}
	for (const auto& range : clears) {
		vh.mutations.emplace_back_deep(vh.mutations.arena(),
		                               MutationRef(MutationRef::ClearRange, range.begin, range.end));
		tr.clear(
		    KeyRangeRef(range.begin.withPrefix(globalConfigKeysPrefix), range.end.withPrefix(globalConfigKeysPrefix)));
	}

	// Record the mutations in this commit into the global configuration history.
	Key historyKey = addVersionStampAtEnd(globalConfigHistoryPrefix);
	ObjectWriter historyWriter(IncludeVersion());
	historyWriter.serialize(vh);
	tr.atomicOp(historyKey, historyWriter.toStringRef(), MutationRef::SetVersionstampedKey);

	// Write version key to trigger update in cluster controller.
	tr.atomicOp(globalConfigVersionKey,
	            LiteralStringRef("0123456789\x00\x00\x00\x00"), // versionstamp
	            MutationRef::SetVersionstampedValue);
}

Key GlobalConfig::prefixedKey(KeyRef key) {
	return key.withPrefix(SpecialKeySpace::getModuleRange(SpecialKeySpace::MODULE::GLOBALCONFIG).begin);