chore(QA,stats): adding a wrapper class for the statistics.

dbcon/mysql/ha_mcs_execplan.cpp

@@ -5287,7 +5287,7 @@ void extractColumnStatistics(TABLE_LIST* table_ptr, gp_walk_info& gwi)
             }
             else
             {
-              auto columnStatisticsVec = columnStatisticsMapIt->second.second;
+              auto& columnStatisticsVec = columnStatisticsMapIt->second.getHistograms();
               columnStatisticsVec.push_back(histogram);
             }
           }

dbcon/mysql/ha_mcs_impl_if.h

@@ -119,9 +119,31 @@ typedef dmlpackage::TableValuesMap TableValuesMap;
 typedef std::map<execplan::CalpontSystemCatalog::TableAliasName, std::pair<int, TABLE_LIST*>> TableMap;
 typedef std::tr1::unordered_map<TABLE_LIST*, std::vector<COND*>> TableOnExprList;
 typedef std::tr1::unordered_map<TABLE_LIST*, uint> TableOuterJoinMap;
+
+struct ColumnStatistics
+{
+  ColumnStatistics(execplan::SimpleColumn column, std::vector<Histogram_json_hb*> histograms)
+   : column(column), histograms(histograms)
+  {
+  }
+  ColumnStatistics() = default;
+
+  execplan::SimpleColumn column;
+  std::vector<Histogram_json_hb*> histograms;
+
+  std::vector<Histogram_json_hb*>& getHistograms()
+  {
+    return histograms;
+  }
+
+  execplan::SimpleColumn& getColumn()
+  {
+    return column;
+  }
+};
+
 using ColumnName = std::string;
-using ColumnStatisticsMap =
+using ColumnStatisticsMap = std::unordered_map<ColumnName, ColumnStatistics>;
-    std::unordered_map<ColumnName, std::pair<execplan::SimpleColumn, std::vector<Histogram_json_hb*>>>;
 using TableStatisticsMap =
     std::unordered_map<SchemaAndTableName, ColumnStatisticsMap, SchemaAndTableNameHash>;
 

dbcon/rbo/rbo_apply_parallel_ces.cpp

@@ -238,11 +238,12 @@ std::optional<std::pair<execplan::SimpleColumn&, Histogram_json_hb*>> chooseKeyC
   }
 
   // TODO take some column and some stats for it!!!
-  for (auto& [columnName, scAndStatisticsVec] : tableColumnsStatisticsIt->second)
+  for (auto& [columnName, columnStatistics] : tableColumnsStatisticsIt->second)
   {
-    auto& [sc, columnStatisticsVec] = scAndStatisticsVec;
+    auto& sc = columnStatistics.getColumn();
-    auto* columnStatistics = chooseStatisticsToUse(columnStatisticsVec);
+    auto& columnStatisticsVec = columnStatistics.getHistograms();
-    return {{sc, columnStatistics}};
+    auto* bestColumnStatistics = chooseStatisticsToUse(columnStatisticsVec);
+    return {{sc, bestColumnStatistics}};
   }
 
   return std::nullopt;
@@ -262,7 +263,7 @@ bool parallelCESFilter(execplan::CalpontSelectExecutionPlan& csep, optimizer::RB
 // Returns optional with bounds if successful, nullopt otherwise
 template <typename T>
 std::optional<details::FilterRangeBounds<T>> populateRangeBounds(Histogram_json_hb* columnStatistics,
-                                                                 optimizer::RBOptimizerContext& ctx)
+                                                                 size_t& maxParallelFactor)
 {
   details::FilterRangeBounds<T> bounds;
 
@@ -280,7 +281,6 @@ std::optional<details::FilterRangeBounds<T>> populateRangeBounds(Histogram_json_
   };
 
   // Get parallel factor from context
-  size_t maxParallelFactor = ctx.getCesOptimizationParallelFactor();
   size_t numberOfUnionUnits = std::min(columnStatistics->get_json_histogram().size(), maxParallelFactor);
   size_t numberOfBucketsPerUnionUnit = columnStatistics->get_json_histogram().size() / numberOfUnionUnits;
 
@@ -343,7 +343,8 @@ execplan::CalpontSelectExecutionPlan::SelectList makeUnionFromTable(
   std::cout << "makeUnionFromTable RC front " << csep.returnedCols().front()->toString() << std::endl;
 
   // TODO char and other numerical types support
-  auto boundsOpt = populateRangeBounds<uint64_t>(columnStatistics, ctx);
+  size_t configuredMaxParallelFactor = ctx.getCesOptimizationParallelFactor();
+  auto boundsOpt = populateRangeBounds<uint64_t>(columnStatistics, configuredMaxParallelFactor);
   if (!boundsOpt.has_value())
   {
     return unionVec;

dbcon/rbo/rulebased_optimizer.h

@@ -145,4 +145,4 @@ bool optimizeCSEP(execplan::CalpontSelectExecutionPlan& root, RBOptimizerContext
 std::string getRewrittenSubTableAlias(const execplan::CalpontSystemCatalog::TableAliasName& table,
                                       const RBOptimizerContext& ctx);
 
-}
+}  // namespace optimizer