Function _bitmap_doinsert

src/backend/access/bitmap/bitmapinsert.c:2544–2609

* _bitmap_doinsert() -- insert an index tuple for a given tuple. */

 * _bitmap_doinsert() -- insert an index tuple for a given tuple.
 */
void
_bitmap_doinsert(Relation rel, ItemPointerData ht_ctid, Datum *attdata, 
				 bool *nulls)
{
	uint64			tidOffset;
	TupleDesc		tupDesc;
	Buffer			metabuf;
	BMMetaPage		metapage;
	Relation		lovHeap, lovIndex;
	ScanKey			scanKeys;
	IndexScanDesc	scanDesc;
	int				attno;

	tupDesc = RelationGetDescr(rel);
	if (tupDesc->natts <= 0)
		return ;

	tidOffset = BM_IPTR_TO_INT(&ht_ctid);

	/* insert a new bit into the corresponding bitmap using the HRL scheme */
	metabuf = _bitmap_getbuf(rel, BM_METAPAGE, BM_READ);
	metapage = _bitmap_get_metapage_data(rel, metabuf);
	_bitmap_open_lov_heapandindex(rel, metapage, &lovHeap, &lovIndex, 
								  RowExclusiveLock);

	LockBuffer(metabuf, BUFFER_LOCK_UNLOCK);

	scanKeys = (ScanKey) palloc0(tupDesc->natts * sizeof(ScanKeyData));

	for (attno = 0; attno < tupDesc->natts; attno++)
	{
		Oid			eq_opr;
		RegProcedure opfuncid;
		ScanKey		scanKey;

		get_sort_group_operators(TupleDescAttr(tupDesc, attno)->atttypid,
								 false, true, false,
								 NULL, &eq_opr, NULL, NULL);
		opfuncid = get_opcode(eq_opr);

		scanKey = (ScanKey) (((char *)scanKeys) + attno * sizeof(ScanKeyData));

		ScanKeyEntryInitialize(scanKey,
							   nulls[attno] ? SK_ISNULL : 0,
							   attno + 1,
							   BTEqualStrategyNumber,
							   InvalidOid,
							   lovIndex->rd_indcollation[attno],
							   opfuncid,
							   attdata[attno]);
	}

	scanDesc = index_beginscan(lovHeap, lovIndex, GetActiveSnapshot(),
							   tupDesc->natts, 0);
	index_rescan(scanDesc, scanKeys, tupDesc->natts, NULL, 0);

	/* insert this new tuple into the bitmap index. */
	inserttuple(rel, metabuf, tidOffset, ht_ctid, tupDesc, attdata, nulls,