Function ExecHashAccumInstrumentation

src/backend/executor/nodeHash.c:3405–3419

* Accumulate instrumentation data from 'hashtable' into an * initially-zeroed HashInstrumentation struct. * * This is used to merge information across successive hash table instances * within a single plan node. We take the maximum values of each interesting * number. The largest nbuckets and largest nbatch values might have occurred * in different instances, so there's some risk of confus

 * in depending on that here, so handle them the same way.
 */
void
ExecHashAccumInstrumentation(HashInstrumentation *instrument,
							 HashJoinTable hashtable)
{
	instrument->nbuckets = Max(instrument->nbuckets,
							   hashtable->nbuckets);
	instrument->nbuckets_original = Max(instrument->nbuckets_original,
										hashtable->nbuckets_original);
	instrument->nbatch = Max(instrument->nbatch,
							 hashtable->nbatch);
	instrument->nbatch_original = Max(instrument->nbatch_original,
									  hashtable->nbatch_original);
	instrument->space_peak = Max(instrument->space_peak,
								 hashtable->spacePeak);
}

/*
 * Allocate 'size' bytes from the currently active HashMemoryChunk