Function ExecHashTableDetachBatch

src/backend/executor/nodeHash.c:3833–3890

* If we are currently attached to a shared hash join batch, detach. If we * are last to detach, clean up. */

 * are last to detach, clean up.
 */
void
ExecHashTableDetachBatch(HashJoinTable hashtable)
{
	if (hashtable->parallel_state != NULL &&
		hashtable->curbatch >= 0)
	{
		int			curbatch = hashtable->curbatch;
		ParallelHashJoinBatch *batch = hashtable->batches[curbatch].shared;

		/* Make sure any temporary files are closed. */
		sts_end_parallel_scan(hashtable->batches[curbatch].inner_tuples);
		sts_end_parallel_scan(hashtable->batches[curbatch].outer_tuples);

		/* Detach from the batch we were last working on. */
		/*
		 * CBDB_PARALLEL: Parallel Hash Left Anti Semi (Not-In) Join(parallel-aware)
		 * If phs_lasj_has_null is true, that means we have found null when building hash table,
		 * there were no batches to detach.
		 */
		if (!hashtable->parallel_state->phs_lasj_has_null && BarrierArriveAndDetach(&batch->batch_barrier))
		{
			/*
			 * Technically we shouldn't access the barrier because we're no
			 * longer attached, but since there is no way it's moving after
			 * this point it seems safe to make the following assertion.
			 */
			Assert(BarrierPhase(&batch->batch_barrier) == PHJ_BATCH_DONE);

			/* Free shared chunks and buckets. */
			while (DsaPointerIsValid(batch->chunks))
			{
				HashMemoryChunk chunk =
				dsa_get_address(hashtable->area, batch->chunks);
				dsa_pointer next = chunk->next.shared;

				dsa_free(hashtable->area, batch->chunks);
				batch->chunks = next;
			}
			if (DsaPointerIsValid(batch->buckets))
			{
				dsa_free(hashtable->area, batch->buckets);
				batch->buckets = InvalidDsaPointer;
			}
		}

		/*
		 * Track the largest batch we've been attached to.  Though each
		 * backend might see a different subset of batches, explain.c will
		 * scan the results from all backends to find the largest value.
		 */
		hashtable->spacePeak =
			Max(hashtable->spacePeak,
				batch->size + sizeof(dsa_pointer_atomic) * hashtable->nbuckets);

		/* Remember that we are not attached to a batch. */
		hashtable->curbatch = -1;
	}
}