Function persistentTstoreStartupReceiver

src/backend/executor/tstoreReceiver.c:388–444

}

static void
persistentTstoreStartupReceiver(DestReceiver *self, int operation, TupleDesc typeinfo)
{
	bool		needtoast = false;
	int			natts = typeinfo->natts;
	int			i;
	PersistentTupleStore *myState = (PersistentTupleStore *) self;
	MemoryContext oldcxt;

	oldcxt = MemoryContextSwitchTo(myState->cxt);
	/* create in-memory tuplestore */
	if (myState->tstore == NULL)
		myState->tstore = tuplestore_begin_heap(true, false, work_mem);
	MemoryContextSwitchTo(oldcxt);

	if (myState->fileset == NULL)
		myState->fileset = get_shareinput_fileset();

	/* create tuplestore on disk */
	Assert(myState->filename);
	Assert(myState->owner);

	/* Check if any columns require detoast work */
	if (myState->detoast)
	{
		for (i = 0; i < natts; i++)
		{
			Form_pg_attribute attr = TupleDescAttr(typeinfo, i);

			if (attr->attisdropped)
				continue;
			if (attr->attlen == -1)
			{
				needtoast = true;
				break;
			}
		}
	}

	/* Set up appropriate callback */
	if (needtoast)
	{
		myState->pub.receiveSlot = persistentTstoreReceiveSlot_detoast;
		/* Create workspace */
		myState->outvalues = (Datum *)
			MemoryContextAlloc(myState->cxt, natts * sizeof(Datum));
		myState->tofree = (Datum *)
			MemoryContextAlloc(myState->cxt, natts * sizeof(Datum));
	}
	else
	{
		myState->pub.receiveSlot = persistentTstoreReceiveSlot_notoast;
		myState->outvalues = NULL;
		myState->tofree = NULL;
	}

}