Method peekLocal

fdbserver/TagPartitionedLogSystem.actor.cpp:881–1082

}

Reference<ILogSystem::IPeekCursor> TagPartitionedLogSystem::peekLocal(UID dbgid,
                                                                      Tag tag,
                                                                      Version begin,
                                                                      Version end,
                                                                      bool useMergePeekCursors,
                                                                      int8_t peekLocality) {
	if (tag.locality >= 0 || tag.locality == tagLocalityUpgraded || tag.locality == tagLocalitySpecial) {
		peekLocality = tag.locality;
	}
	ASSERT(peekLocality >= 0 || peekLocality == tagLocalityUpgraded || tag.locality == tagLocalitySpecial);

	int bestSet = -1;
	bool foundSpecial = false;
	int logCount = 0;
	for (int t = 0; t < tLogs.size(); t++) {
		if (tLogs[t]->logServers.size() && tLogs[t]->locality != tagLocalitySatellite) {
			logCount++;
		}
		if (tLogs[t]->logServers.size() &&
		    (tLogs[t]->locality == tagLocalitySpecial || tLogs[t]->locality == tagLocalityUpgraded ||
		     tLogs[t]->locality == peekLocality || peekLocality == tagLocalityUpgraded ||
		     peekLocality == tagLocalitySpecial)) {
			if (tLogs[t]->locality == tagLocalitySpecial || tLogs[t]->locality == tagLocalityUpgraded) {
				foundSpecial = true;
			}
			bestSet = t;
			break;
		}
	}
	if (bestSet == -1) {
		TraceEvent("TLogPeekLocalNoBestSet", dbgid)
		    .detail("Tag", tag.toString())
		    .detail("Begin", begin)
		    .detail("End", end)
		    .detail("LogCount", logCount);
		if (useMergePeekCursors || logCount > 1) {
			throw worker_removed();
		} else {
			return makeReference<ILogSystem::ServerPeekCursor>(
			    Reference<AsyncVar<OptionalInterface<TLogInterface>>>(), tag, begin, getPeekEnd(), false, false);
		}
	}

	if (begin >= tLogs[bestSet]->startVersion) {
		TraceEvent("TLogPeekLocalBestOnly", dbgid)
		    .detail("Tag", tag.toString())
		    .detail("Begin", begin)
		    .detail("End", end)
		    .detail("BestSet", bestSet)
		    .detail("BestSetStart", tLogs[bestSet]->startVersion)
		    .detail("LogId", tLogs[bestSet]->logServers[tLogs[bestSet]->bestLocationFor(tag)]->get().id());
		if (useMergePeekCursors) {
			return makeReference<ILogSystem::MergedPeekCursor>(tLogs[bestSet]->logServers,
			                                                   tLogs[bestSet]->bestLocationFor(tag),
			                                                   tLogs[bestSet]->logServers.size() + 1 -
			                                                       tLogs[bestSet]->tLogReplicationFactor,
			                                                   tag,
			                                                   begin,