// NOTE: this MUST be done before reading unpartitionedSources, so we see a consistent view of the unpartitioned sources
drivers.add(new WeakReference<>(driver));
if (partitionedSplit != null) {
// TableScanOperator requires partitioned split to be added before the first call to process
driver.updateSource(new TaskSource(partitionedSourceId, ImmutableSet.of(partitionedSplit), true));
}
// add unpartitioned sources
for (TaskSource source : unpartitionedSources.values()) {
driver.updateSource(source);