Function extension_rumrescan_core

pg_documentdb/src/index_am/rum.c:1112–1246

void
extension_rumrescan_core(IndexScanDesc scan, ScanKey scankey, int nscankeys,
						 ScanKey orderbys, int norderbys,
						 IndexAmRoutine *coreRoutine)
{
	bool supportsOrderedOperatorScans = false;
	GetMultikeyStatusFunc multiKeyStatusFunc = NULL;
	CanOrderInIndexScan isIndexScanOrdered = NULL;
	if (GetCompositeOpClassWithProps(scan->indexRelation,
									 &supportsOrderedOperatorScans, &multiKeyStatusFunc,
									 &isIndexScanOrdered))
	{
		/* Copy the scan keys to our scan */
		if (scankey && scan->numberOfKeys > 0)
		{
			memmove(scan->keyData, scankey,
					scan->numberOfKeys * sizeof(ScanKeyData));
		}
		if (orderbys && scan->numberOfOrderBys > 0)
		{
			memmove(scan->orderByData, orderbys,
					scan->numberOfOrderBys * sizeof(ScanKeyData));
		}

		/* get the opaque scans */
		DocumentDBRumIndexState *outerScanState =
			(DocumentDBRumIndexState *) scan->opaque;

		int numColumns = GetCompositeOpClassPathCount(
			scan->indexRelation->rd_opcoptions[0]);
		if (outerScanState->multiKeyStatus == IndexMultiKeyStatus_Unknown)
		{
			if (multiKeyStatusFunc != NULL)
			{
				outerScanState->multiKeyStatus = multiKeyStatusFunc(scan->indexRelation);
			}
			else
			{
				outerScanState->multiKeyStatus =
					CheckIndexHasArrays(scan->indexRelation, coreRoutine);
			}

			/* Check if we are producing reduced index terms in this index */
			BsonGinCompositePathOptions *options =
				(BsonGinCompositePathOptions *) scan->indexRelation->rd_opcoptions[0];
			if (options->enableCompositeReducedCorrelatedTerms &&
				outerScanState->multiKeyStatus == IndexMultiKeyStatus_HasArrays &&
				numColumns > 1)
			{
				/* Check if we have correlated reduced terms */
				outerScanState->hasCorrelatedReducedTerms = CheckIndexHasReducedTerms(
					scan->indexRelation, coreRoutine);
			}
		}

		ScanKey innerOrderBy = NULL;
		int32_t nInnerorderbys = 0;
		innerOrderBy = orderbys;