dblink_write implement [FEAT MERGE]

Co-authored-by: zzg19950727 <1071026277@qq.com>
Co-authored-by: xianyu-w <707512433@qq.com>

src/sql/optimizer/ob_log_link_scan.cpp

@@ -0,0 +1,46 @@
+// Copyright 2010-2018 Alibaba Inc. All Rights Reserved.
+// Author:
+//   ethan.xy@antfin.com
+
+#define USING_LOG_PREFIX SQL_OPT
+#include "sql/optimizer/ob_log_link_scan.h"
+#include "sql/resolver/expr/ob_expr_info_flag.h"
+
+using namespace oceanbase::sql;
+using namespace oceanbase::common;
+using namespace oceanbase::sql::log_op_def;
+
+namespace oceanbase
+{
+namespace sql
+{
+
+ObLogLinkScan::ObLogLinkScan(ObLogPlan &plan)
+  : ObLogLink(plan)
+{}
+
+int ObLogLinkScan::allocate_expr_post(ObAllocExprContext &ctx)
+{
+  int ret = OB_SUCCESS;
+  for (int64_t i = 0; OB_SUCC(ret) && i < output_exprs_.count(); ++i) {
+    ObRawExpr *expr = output_exprs_.at(i);
+    if (OB_ISNULL(expr)) {
+      ret = OB_ERR_UNEXPECTED;
+      LOG_WARN("null expr", K(ret));
+    } else if (OB_FAIL(mark_expr_produced(expr,
+                                          branch_id_,
+                                          id_,
+                                          ctx))) {
+      LOG_WARN("failed to mark expr as produced", K(branch_id_), K(ret));
+    }
+  }
+  if (OB_SUCC(ret)) {
+    if (OB_FAIL(ObLogicalOperator::allocate_expr_post(ctx))) {
+      LOG_WARN("failed to allocate_expr_post", K(ret));
+    } else { /*do nothing*/ }
+  }
+  return ret;
+}
+
+} // namespace sql
+} // namespace oceanbase