Function tuplesort_initialize_shared

src/backend/utils/sort/tuplesort.c:4674–4690

* tuplesort_initialize_shared - initialize shared tuplesort state * * Must be called from leader process before workers are launched, to * establish state needed up-front for worker tuplesortstates. nWorkers * should match the argument passed to tuplesort_estimate_shared(). */

 * should match the argument passed to tuplesort_estimate_shared().
 */
void
tuplesort_initialize_shared(Sharedsort *shared, int nWorkers, dsm_segment *seg)
{
	int			i;

	Assert(nWorkers > 0);

	SpinLockInit(&shared->mutex);
	shared->currentWorker = 0;
	shared->workersFinished = 0;
	SharedFileSetInit(&shared->fileset, seg);
	shared->nTapes = nWorkers;
	for (i = 0; i < nWorkers; i++)
	{
		shared->tapes[i].firstblocknumber = 0L;
	}
}

/*
 * tuplesort_attach_shared - attach to shared tuplesort state