[FEAT MERGE] implement dynamic sampling

src/sql/optimizer/ob_opt_est_cost_model.h

@@ -19,6 +19,7 @@
 #include "sql/rewrite/ob_query_range_provider.h"
 #include "sql/optimizer/ob_opt_default_stat.h"
 #include "sql/resolver/dml/ob_dml_stmt.h"
+#include "share/stat/ob_opt_ds_stat.h"
 
 namespace oceanbase
 {
@@ -36,6 +37,7 @@ enum RowCountEstMethod
   DEFAULT_STAT,
   BASIC_STAT,    //use min/max/ndv to estimate row count
   STORAGE_STAT, //use storage layer to estimate row count
+  DYNAMIC_SAMPLING_STAT //use dynamic sampling to estimate row count
 };
 
 // all the table meta info need to compute cost
@@ -52,9 +54,7 @@ struct ObTableMetaInfo
       part_size_(0),
       average_row_size_(0),
       row_count_(0),
-      cost_est_type_(ObEstimateType::OB_CURRENT_STAT_EST),
       has_opt_stat_(false),
-      is_empty_table_(false),
       micro_block_count_(-1)
   { }
   virtual ~ObTableMetaInfo()
@@ -65,8 +65,7 @@ struct ObTableMetaInfo
   TO_STRING_KV(K_(ref_table_id), K_(part_count), K_(micro_block_size),
                K_(part_size), K_(average_row_size), K_(table_column_count),
                K_(table_rowkey_count), K_(table_row_count), K_(row_count),
-               K_(cost_est_type), K_(has_opt_stat),
-               K_(is_empty_table), K_(micro_block_count));
+               K_(micro_block_count));
 
   /// the following fields come from schema info
   uint64_t ref_table_id_; //ref table id
@@ -82,9 +81,7 @@ struct ObTableMetaInfo
   double average_row_size_; //main table best partition average row size
 
   double row_count_;  // row count after filters, estimated by stat manager
-  ObEstimateType cost_est_type_; // cost estimation type
   bool has_opt_stat_;
-  bool is_empty_table_;
   int64_t micro_block_count_;  // main table micro block count
 private:
   DISALLOW_COPY_AND_ASSIGN(ObTableMetaInfo);