reduce query pre-exec copies

Author: akroviakov

omniscidb/ArrowStorage/ArrowStorage.cpp

@@ -337,7 +337,9 @@ void ArrowStorage::fetchVarLenArrayData(const TableData& table,
   }
 }
 
-TableFragmentsInfo ArrowStorage::getTableMetadata(int db_id, int table_id) const {
+std::shared_ptr<const TableFragmentsInfo> ArrowStorage::getTableMetadata(
+    int db_id,
+    int table_id) const {
   mapd_shared_lock<mapd_shared_mutex> data_lock(data_mutex_);
   CHECK_EQ(db_id, db_id_);
   CHECK_EQ(tables_.count(table_id), (size_t)1);
@@ -349,11 +351,11 @@ TableFragmentsInfo ArrowStorage::getTableMetadata(int db_id, int table_id) const
     return getEmptyTableMetadata(table_id);
   }
 
-  TableFragmentsInfo res;
-  res.setPhysicalNumTuples(table.row_count);
+  std::shared_ptr<TableFragmentsInfo> res = std::make_shared<TableFragmentsInfo>();
+  res->setPhysicalNumTuples(table.row_count);
   for (size_t frag_idx = 0; frag_idx < table.fragments.size(); ++frag_idx) {
     auto& frag = table.fragments[frag_idx];
-    auto& frag_info = res.fragments.emplace_back();
+    auto& frag_info = res->fragments.emplace_back();
     frag_info.fragmentId = static_cast<int>(frag_idx + 1);
     frag_info.physicalTableId = table_id;
     frag_info.setPhysicalNumTuples(frag.row_count);
@@ -364,23 +366,24 @@ TableFragmentsInfo ArrowStorage::getTableMetadata(int db_id, int table_id) const
       frag_info.setChunkMetadata(columnId(col_idx), frag.metadata[col_idx]);
     }
   }
-  res.setTableStats(table.table_stats);
+  res->setTableStats(table.table_stats);
   return res;
 }
 
-TableFragmentsInfo ArrowStorage::getEmptyTableMetadata(int table_id) const {
-  TableFragmentsInfo res;
-  res.setPhysicalNumTuples(0);
+std::shared_ptr<TableFragmentsInfo> ArrowStorage::getEmptyTableMetadata(
+    int table_id) const {
+  std::shared_ptr<TableFragmentsInfo> res = std::make_shared<TableFragmentsInfo>();
+  res->setPhysicalNumTuples(0);
 
   // Executor requires dummy empty fragment for empty tables
-  FragmentInfo& empty_frag = res.fragments.emplace_back();
+  FragmentInfo& empty_frag = res->fragments.emplace_back();
   empty_frag.fragmentId = 0;
   empty_frag.setPhysicalNumTuples(0);
   empty_frag.deviceIds.push_back(0);  // Data_Namespace::DISK_LEVEL
   empty_frag.deviceIds.push_back(0);  // Data_Namespace::CPU_LEVEL
   empty_frag.deviceIds.push_back(0);  // Data_Namespace::GPU_LEVEL
   empty_frag.physicalTableId = table_id;
-  res.fragments.push_back(empty_frag);
+  res->fragments.push_back(empty_frag);
 
   return res;
 }
@@ -828,8 +831,6 @@ void ArrowStorage::refragmentTable(TableData& table,
                 meta->fillChunkStats(computeStats(
                     col_arr->Slice(frag.offset, frag.row_count * elems_count), col_type));
               } else {
-                int32_t min = 0;
-                int32_t max = -1;
                 meta->fillChunkStats(0, -1, /*has_nulls=*/true);
               }
               frag.metadata[col_idx] = meta;

omniscidb/ArrowStorage/ArrowStorage.h

@@ -73,7 +73,8 @@ class ArrowStorage : public SimpleSchemaProvider, public AbstractDataProvider {
   std::unique_ptr<Data_Namespace::AbstractDataToken> getZeroCopyColumnData(
       const ColumnRef& col_ref) override;
 
-  TableFragmentsInfo getTableMetadata(int db_id, int table_id) const override;
+  std::shared_ptr<const TableFragmentsInfo> getTableMetadata(int db_id,
+                                                             int table_id) const override;
 
   const DictDescriptor* getDictMetadata(int dict_id, bool load_dict = true) override;
 
@@ -217,7 +218,7 @@ class ArrowStorage : public SimpleSchemaProvider, public AbstractDataProvider {
                       std::shared_ptr<arrow::Schema> rhs);
   ChunkStats computeStats(std::shared_ptr<arrow::ChunkedArray> arr,
                           const hdk::ir::Type* type);
-  TableFragmentsInfo getEmptyTableMetadata(int table_id) const;
+  std::shared_ptr<TableFragmentsInfo> getEmptyTableMetadata(int table_id) const;
   void fetchFixedLenData(const TableData& table,
                          size_t frag_idx,
                          size_t col_idx,

omniscidb/DataMgr/AbstractBufferMgr.h

@@ -103,7 +103,9 @@ class AbstractBufferMgr {
 
   virtual const DictDescriptor* getDictMetadata(int dict_id, bool load_dict = true) = 0;
 
-  virtual TableFragmentsInfo getTableMetadata(int db_id, int table_id) const = 0;
+  virtual std::shared_ptr<const TableFragmentsInfo> getTableMetadata(
+      int db_id,
+      int table_id) const = 0;
 
   // Buffer API
   virtual AbstractBuffer* alloc(const size_t numBytes = 0) = 0;

omniscidb/DataMgr/BufferMgr/BufferMgr.h

@@ -180,9 +180,10 @@ class BufferMgr : public AbstractBufferMgr {  // implements
     return nullptr;
   }
 
-  TableFragmentsInfo getTableMetadata(int db_id, int table_id) const override {
+  std::shared_ptr<const TableFragmentsInfo> getTableMetadata(int db_id, int table_id)
+      const override {
     UNREACHABLE();
-    return TableFragmentsInfo{};
+    return std::make_shared<TableFragmentsInfo>(TableFragmentsInfo{});
   }
 
   // Buffer API

omniscidb/DataMgr/DataMgr.cpp

@@ -525,7 +525,8 @@ const DictDescriptor* DataMgr::getDictMetadata(int dict_id, bool load_dict) cons
   return getPersistentStorageMgr()->getDictMetadata(dict_id, load_dict);
 }
 
-TableFragmentsInfo DataMgr::getTableMetadata(int db_id, int table_id) const {
+std::shared_ptr<const TableFragmentsInfo> DataMgr::getTableMetadata(int db_id,
+                                                                    int table_id) const {
   return getPersistentStorageMgr()->getTableMetadata(db_id, table_id);
 }
 

omniscidb/DataMgr/DataMgr.h

@@ -214,7 +214,8 @@ class DataMgr {
 
   const DictDescriptor* getDictMetadata(int dict_id, bool load_dict = true) const;
 
-  TableFragmentsInfo getTableMetadata(int db_id, int table_id) const;
+  std::shared_ptr<const TableFragmentsInfo> getTableMetadata(int db_id,
+                                                             int table_id) const;
 
   BufferProvider* getBufferProvider() const { return buffer_provider_.get(); }
 

omniscidb/DataMgr/DataMgrDataProvider.cpp

@@ -35,7 +35,9 @@ DataMgrDataProvider::getZeroCopyColumnData(const ColumnRef& col_ref) {
   return data_mgr_->getZeroCopyColumnData(col_ref);
 }
 
-TableFragmentsInfo DataMgrDataProvider::getTableMetadata(int db_id, int table_id) const {
+std::shared_ptr<const TableFragmentsInfo> DataMgrDataProvider::getTableMetadata(
+    int db_id,
+    int table_id) const {
   return data_mgr_->getTableMetadata(db_id, table_id);
 }
 

omniscidb/DataMgr/DataMgrDataProvider.h

@@ -38,7 +38,8 @@ class DataMgrDataProvider : public DataProvider {
   std::unique_ptr<Data_Namespace::AbstractDataToken> getZeroCopyColumnData(
       const ColumnRef& col_ref) override;
 
-  TableFragmentsInfo getTableMetadata(int db_id, int table_id) const override;
+  std::shared_ptr<const TableFragmentsInfo> getTableMetadata(int db_id,
+                                                             int table_id) const override;
 
   const DictDescriptor* getDictMetadata(int dict_id,
                                         bool load_dict = true) const override;

omniscidb/DataMgr/PersistentStorageMgr/PersistentStorageMgr.cpp

@@ -133,7 +133,9 @@ const DictDescriptor* PersistentStorageMgr::getDictMetadata(int dict_id, bool lo
   return nullptr;
 }
 
-TableFragmentsInfo PersistentStorageMgr::getTableMetadata(int db_id, int table_id) const {
+std::shared_ptr<const TableFragmentsInfo> PersistentStorageMgr::getTableMetadata(
+    int db_id,
+    int table_id) const {
   return getStorageMgrForTableKey({db_id, table_id})->getTableMetadata(db_id, table_id);
 }
 

omniscidb/DataMgr/PersistentStorageMgr/PersistentStorageMgr.h

@@ -56,7 +56,8 @@ class PersistentStorageMgr : public AbstractBufferMgr {
 
   const DictDescriptor* getDictMetadata(int dict_id, bool load_dict = true);
 
-  TableFragmentsInfo getTableMetadata(int db_id, int table_id) const override;
+  std::shared_ptr<const TableFragmentsInfo> getTableMetadata(int db_id,
+                                                             int table_id) const override;
 
   void registerDataProvider(int schema_id, std::shared_ptr<AbstractBufferMgr>);