Function table_scan_getnextslot

src/include/access/tableam.h:1235–1249

* Return next tuple from `scan`, store in slot. */

 * Return next tuple from `scan`, store in slot.
 */
static inline bool
table_scan_getnextslot(TableScanDesc sscan, ScanDirection direction, TupleTableSlot *slot)
{
	slot->tts_tableOid = RelationGetRelid(sscan->rs_rd);

	/*
	 * We don't expect direct calls to table_scan_getnextslot with valid
	 * CheckXidAlive for catalog or regular tables.  See detailed comments in
	 * xact.c where these variables are declared.
	 */
	if (unlikely(TransactionIdIsValid(CheckXidAlive) && !bsysscan))
		elog(ERROR, "unexpected table_scan_getnextslot call during logical decoding");

	return sscan->rs_rd->rd_tableam->scan_getnextslot(sscan, direction, slot);
}

/* ----------------------------------------------------------------------------
 * TID Range scanning related functions.