//---------------------------------------------------------------------------
// @function:
// CPhysicalStreamAgg::PosCovering
//
// @doc:
// Construct order spec on grouping column so that it covers required
// order spec, the function returns NULL if no covering order spec
// can be created
//
//---------------------------------------------------------------------------
COrderSpec *
CPhysicalStreamAgg::PosCovering
(
IMemoryPool *mp,
COrderSpec *posRequired,
CColRefArray *pdrgpcrGrp
)
const
{
GPOS_ASSERT(NULL != posRequired);
if (0 == posRequired->UlSortColumns())
{
// required order must be non-empty
return NULL;
}
// create a set of required sort columns
CColRefSet *pcrsReqd = posRequired->PcrsUsed(mp);
COrderSpec *pos = NULL;
CColRefSet *pcrsGrpCols = GPOS_NEW(mp) CColRefSet(mp, pdrgpcrGrp);
if (pcrsGrpCols->ContainsAll(pcrsReqd))
{
// required order columns are included in grouping columns, we can
// construct a covering order spec
pos = GPOS_NEW(mp) COrderSpec(mp);
// extract order expressions from required order
const ULONG ulReqdSortCols = posRequired->UlSortColumns();
for (ULONG ul = 0; ul < ulReqdSortCols; ul++)
{
CColRef *colref = const_cast<CColRef *>(posRequired->Pcr(ul));
IMDId *mdid = posRequired->GetMdIdSortOp(ul);
COrderSpec::ENullTreatment ent = posRequired->Ent(ul);
mdid->AddRef();
pos->Append(mdid, colref, ent);
}
// augment order with remaining grouping columns
const ULONG size = pdrgpcrGrp->Size();
for (ULONG ul = 0; ul < size; ul++)
{
CColRef *colref = (*pdrgpcrGrp)[ul];
if (!pcrsReqd->FMember(colref))
{
IMDId *mdid = colref->RetrieveType()->GetMdidForCmpType(IMDType::EcmptL);
mdid->AddRef();
pos->Append(mdid, colref, COrderSpec::EntLast);
}
}
}
pcrsGrpCols->Release();
pcrsReqd->Release();
return pos;
}
//---------------------------------------------------------------------------
// @function:
// CPhysicalStreamAgg::InitOrderSpec
//
// @doc:
// Initialize the order spec using the given array of columns
//
//---------------------------------------------------------------------------
void
CPhysicalStreamAgg::InitOrderSpec
(
IMemoryPool *mp,
CColRefArray *pdrgpcrOrder
)
{
GPOS_ASSERT(NULL != pdrgpcrOrder);
CRefCount::SafeRelease(m_pos);
m_pos = GPOS_NEW(mp) COrderSpec(mp);
const ULONG size = pdrgpcrOrder->Size();
for (ULONG ul = 0; ul < size; ul++)
{
CColRef *colref = (*pdrgpcrOrder)[ul];
// TODO: 12/21/2011 - ; this seems broken: a colref must not embed
// a pointer to a cached object
gpmd::IMDId *mdid = colref->RetrieveType()->GetMdidForCmpType(IMDType::EcmptL);
mdid->AddRef();
m_pos->Append(mdid, colref, COrderSpec::EntLast);
}
}
