yjhjstz commented on code in PR #1452: URL: https://github.com/apache/cloudberry/pull/1452#discussion_r2570158623
########## src/backend/gporca/libgpopt/src/xforms/CXformDynamicGet2ParallelAppendTableScan.cpp: ########## @@ -0,0 +1,192 @@ +/*------------------------------------------------------------------------- + * + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + * + * CXformDynamicGet2ParallelAppendTableScan.cpp + * + * IDENTIFICATION + * src/backend/gporca/libgpopt/src/xforms/CXformDynamicGet2ParallelAppendTableScan.cpp + * + *------------------------------------------------------------------------- + */ + +#include "gpopt/xforms/CXformDynamicGet2ParallelAppendTableScan.h" + +#include "gpos/base.h" + +#include "gpopt/hints/CHintUtils.h" +#include "gpopt/metadata/CTableDescriptor.h" +#include "gpopt/operators/CLogicalDynamicGet.h" +#include "gpopt/operators/CPhysicalParallelAppendTableScan.h" +#include "gpopt/optimizer/COptimizerConfig.h" + +// Forward declarations for gpdbwrappers functions +namespace gpdb { +bool IsParallelModeOK(void); +} + +using namespace gpopt; + +// Use gpdbwrappers for parallel checks +extern int max_parallel_workers_per_gather; + +//--------------------------------------------------------------------------- +// @function: +// CXformDynamicGet2ParallelAppendTableScan::CXformDynamicGet2ParallelAppendTableScan +// +// @doc: +// Ctor +// +//--------------------------------------------------------------------------- +CXformDynamicGet2ParallelAppendTableScan::CXformDynamicGet2ParallelAppendTableScan( + CMemoryPool *mp) + : CXformImplementation( + // pattern + GPOS_NEW(mp) CExpression(mp, GPOS_NEW(mp) CLogicalDynamicGet(mp))) +{ +} + +// compute xform promise for a given expression handle +CXform::EXformPromise +CXformDynamicGet2ParallelAppendTableScan::Exfp(CExpressionHandle &exprhdl) const +{ + // Check if parallel plans are enabled in context and parallel processing in safe + if (!gpdb::IsParallelModeOK()) + { + return CXform::ExfpNone; + } + + CLogicalDynamicGet *popGet = CLogicalDynamicGet::PopConvert(exprhdl.Pop()); + CTableDescriptor *ptabdesc = popGet->Ptabdesc(); + + // Don't use parallel append for replicated tables + if (ptabdesc->GetRelDistribution() == IMDRelation::EreldistrReplicated || + ptabdesc->GetRelDistribution() == IMDRelation::EreldistrMasterOnly || + COptCtxt::PoctxtFromTLS()->HasReplicatedTables()) + { + return CXform::ExfpNone; + } + + // For AO/AOCO tables, check segfilecount early to avoid useless transformation + CMDAccessor *md_accessor = COptCtxt::PoctxtFromTLS()->Pmda(); + const IMDRelation *pmdrel = md_accessor->RetrieveRel(ptabdesc->MDId()); + IMDRelation::Erelstoragetype storage_type = pmdrel->RetrieveRelStorageType(); + + // Check if this is an AO/AOCO table + if (storage_type == IMDRelation::ErelstorageAppendOnlyRows || + storage_type == IMDRelation::ErelstorageAppendOnlyCols) + { + INT seg_file_count = pmdrel->SegFileCount(); + // Only reject if segfilecount is explicitly known to be 0 or 1 + // -1 means unknown (e.g., from DXL deserialization), so allow parallel in that case + if (seg_file_count >= 0 && seg_file_count <= 1) + { + // If segfilecount is 0 or 1, parallel execution is pointless + // Reject parallel scan early in promise phase + GPOS_TRACE_FORMAT("CXformGet2ParallelTableScan rejected for table %ls: AO/AOCO table has segfilecount=%d (needs >1 for parallel scan)", Review Comment: CXformGet2ParallelTableScan rejected -> CXformDynamicGet2ParallelAppendTableScan -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
