presto-main/src/main/java/io/prestosql/operator/aggregation/builder/MergingHashAggregationBuilder.java/MergingHashAggregationBuilder/rebuildHashAggregationBuilder
class MergingHashAggregationBuilder:    private void rebuildHashAggregationBuilder()
    {
        this.hashAggregationBuilder = new InMemoryHashAggregationBuilder(
                accumulatorFactories,
                step,
                expectedGroups,
                groupByTypes,
                groupByPartialChannels,
                hashChannel,
                operatorContext,
                Optional.of(DataSize.succinctBytes(0)),
                Optional.of(overwriteIntermediateChannelOffset),
                joinCompiler,
                // TODO: merging should also yield on memory reservations
                () -> true);
    }