SetMultimap<Symbol, Integer> indexLookupToProbeInput = mapIndexSourceLookupSymbolToProbeKeyInput(node, probeKeyLayout);
LocalExecutionPlanContext indexContext = context.createIndexSourceSubContext(new IndexSourceContext(indexLookupToProbeInput));
PhysicalOperation indexSource = node.getIndexSource().accept(this, indexContext);
List<Integer> indexChannels = getChannelsForSymbols(indexSymbols, indexSource.getLayout());
IndexBuildDriverFactoryProvider indexBuildDriverFactoryProvider = new IndexBuildDriverFactoryProvider(
indexContext.getNextOperatorId(),
indexContext.isInputDriver(),
indexSource.getOperatorFactories());
IndexLookupSourceSupplier indexLookupSourceSupplier = new IndexLookupSourceSupplier(