Method generateAggregateDistincts

src/jrd/optimizer/Optimizer.cpp:1363–1432

//

void Optimizer::generateAggregateDistincts(MapNode* map)
{
	dsc descriptor;
	dsc* desc = &descriptor;

	for (auto from : map->sourceList)
	{
		auto aggNode = nodeAs<AggNode>(from);

		if (aggNode && aggNode->distinct)
		{
			// Build the sort key definition. Turn cstrings into varying text.
			aggNode->arg->getDesc(tdbb, csb, desc);

			if (desc->dsc_dtype == dtype_cstring)
			{
				desc->dsc_dtype = dtype_varying;
				desc->dsc_length++;
			}

			const auto asb = FB_NEW_POOL(getPool()) AggregateSort(getPool());

			asb->intl = desc->isText() && desc->getTextType() != ttype_none &&
				desc->getTextType() != ttype_binary && desc->getTextType() != ttype_ascii;

			sort_key_def* sort_key = asb->keyItems.getBuffer(asb->intl ? 2 : 1);
			sort_key->setSkdOffset();

			if (asb->intl)
			{
				const USHORT key_length = ROUNDUP(INTL_key_length(tdbb,
					INTL_TEXT_TO_INDEX(desc->getTextType()), desc->getStringLength()), sizeof(SINT64));

				sort_key->setSkdLength(SKD_bytes, key_length);
				sort_key->skd_flags = SKD_ascending;
				sort_key->skd_vary_offset = 0;

				++sort_key;
				sort_key->setSkdOffset(&sort_key[-1]);
				asb->length = sort_key->getSkdOffset();
			}

			fb_assert(desc->dsc_dtype < FB_NELEM(sort_dtypes));
			sort_key->setSkdLength(sort_dtypes[desc->dsc_dtype], desc->dsc_length);

			if (!sort_key->skd_dtype)
				ERR_post(Arg::Gds(isc_invalid_sort_datatype) << Arg::Str(DSC_dtype_tostring(desc->dsc_dtype)));

			if (desc->dsc_dtype == dtype_varying)
			{
				// allocate space to store varying length
				sort_key->skd_vary_offset = sort_key->getSkdOffset() + ROUNDUP(desc->dsc_length, sizeof(SLONG));
				asb->length = sort_key->skd_vary_offset + sizeof(USHORT);
			}
			else
				asb->length += sort_key->getSkdLength();

			asb->length = ROUNDUP(asb->length, sizeof(SLONG));