Add scan option in das scan op

src/share/ob_i_tablet_scan.cpp

@@ -25,6 +25,7 @@ namespace common
 OB_SERIALIZE_MEMBER(ObLimitParam, offset_, limit_);
 OB_SERIALIZE_MEMBER(SampleInfo, table_id_, method_, scope_, percent_, seed_, force_block_);
 OB_SERIALIZE_MEMBER(ObEstRowCountRecord, table_id_, table_type_, version_range_, logical_row_count_, physical_row_count_);
+OB_SERIALIZE_MEMBER(ObTableScanOption, io_read_batch_size_, io_read_gap_size_, storage_rowsets_size_);
 
 uint64_t SampleInfo::hash(uint64_t seed) const
 {

src/share/ob_i_tablet_scan.h

@@ -96,6 +96,49 @@ struct SampleInfo
   OB_UNIS_VERSION(1);
 };
 
+struct ObTableScanOption
+{
+  OB_UNIS_VERSION(1);
+public:
+  static const int64_t MAX_IO_READ_BATCH_SIZE = 16_MB;
+  static const int64_t MAX_STORAGE_ROWSETS_SIZE = (1 << 20);
+  ObTableScanOption() :
+      io_read_batch_size_(0),
+      io_read_gap_size_(0),
+      storage_rowsets_size_(1)
+  {}
+  bool is_io_valid() const
+  {
+    return (io_read_batch_size_ >= 0 && io_read_batch_size_ <= MAX_IO_READ_BATCH_SIZE &&
+            io_read_gap_size_ >= 0 && io_read_gap_size_ < io_read_batch_size_);
+  }
+  bool is_rowsets_valid() const
+  {
+    return storage_rowsets_size_ > 0 && storage_rowsets_size_ <= MAX_STORAGE_ROWSETS_SIZE;
+  }
+  void reset()
+  {
+    io_read_batch_size_ = 0;
+    io_read_gap_size_ = 0;
+    storage_rowsets_size_ = 1;
+  }
+  ObTableScanOption &operator=(const ObTableScanOption &opt)
+  {
+    if (this == &opt) {
+    } else {
+      io_read_batch_size_ = opt.io_read_batch_size_;
+      io_read_gap_size_ = opt.io_read_gap_size_;
+      storage_rowsets_size_ = opt.storage_rowsets_size_;
+    }
+    return *this;
+  }
+  TO_STRING_KV(K_(io_read_batch_size), K_(io_read_gap_size), K_(storage_rowsets_size));
+
+  int64_t io_read_batch_size_;
+  int64_t io_read_gap_size_;
+  int64_t storage_rowsets_size_;
+};
+
 struct ObLimitParam
 {
   int64_t offset_;

src/sql/das/ob_das_scan_op.cpp

@@ -62,7 +62,8 @@ OB_SERIALIZE_MEMBER(ObDASScanCtDef,
                     trans_info_expr_,
                     group_by_column_ids_,
                     ir_scan_type_,
-                    rowkey_exprs_);
+                    rowkey_exprs_,
+                    table_scan_opt_);
 
 OB_DEF_SERIALIZE(ObDASScanRtDef)
 {

src/sql/das/ob_das_scan_op.h

@@ -48,7 +48,8 @@ public:
       external_file_format_str_(alloc),
       trans_info_expr_(nullptr),
       ir_scan_type_(ObTSCIRScanType::OB_NOT_A_SPEC_SCAN),
-      rowkey_exprs_(alloc)
+      rowkey_exprs_(alloc),
+      table_scan_opt_()
   { }
   //in das scan op, column described with column expr
   virtual bool has_expr() const override { return true; }
@@ -83,7 +84,8 @@ public:
                        K_(external_file_location),
                        KPC_(trans_info_expr),
                        K_(ir_scan_type),
-                       K_(rowkey_exprs));
+                       K_(rowkey_exprs),
+                       K_(table_scan_opt));
   common::ObTableID ref_table_id_;
   UIntFixedArray access_column_ids_;
   int64_t schema_version_;
@@ -105,6 +107,7 @@ public:
   ObExpr *trans_info_expr_; // transaction information pseudo-column
   ObTSCIRScanType ir_scan_type_; // specify retrieval scan type
   sql::ExprFixedArray rowkey_exprs_; // store rowkey exprs for index lookup
+  ObTableScanOption table_scan_opt_;
 };
 
 struct ObDASScanRtDef : ObDASBaseRtDef