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src/sql/engine/expr/ob_expr_func_dump.cpp

@@ -0,0 +1,698 @@
+/**
+ * Copyright (c) 2021 OceanBase
+ * OceanBase CE is licensed under Mulan PubL v2.
+ * You can use this software according to the terms and conditions of the Mulan PubL v2.
+ * You may obtain a copy of Mulan PubL v2 at:
+ *          http://license.coscl.org.cn/MulanPubL-2.0
+ * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
+ * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
+ * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
+ * See the Mulan PubL v2 for more details.
+ */
+
+#define USING_LOG_PREFIX SQL_ENG
+
+#include <string.h>
+#include "share/object/ob_obj_cast.h"
+#include "sql/parser/ob_item_type.h"
+#include "sql/engine/expr/ob_expr_func_dump.h"
+#include "sql/session/ob_sql_session_info.h"
+#include "sql/engine/expr/ob_expr_util.h"
+
+namespace oceanbase {
+using namespace common;
+namespace sql {
+
+const int64_t MAX_DUMP_BUFFER_SIZE = 1024;
+const char* CONST_HEADER = "Typ=%d Len=%ld: ";
+
+enum ReturnFormat {
+  RF_OB_SEPC = 0,
+  RF_OCT = 8,     // 8
+  RF_DEC = 10,    // 10
+  RF_HEX = 16,    // 16
+  RF_ASCII = 17,  // 17
+};
+
+ObExprFuncDump::ObExprFuncDump(ObIAllocator& alloc)
+    : ObStringExprOperator(alloc, T_FUN_SYS_DUMP, N_DUMP, MORE_THAN_ZERO)
+{}
+
+ObExprFuncDump::~ObExprFuncDump()
+{}
+
+int print_value(char* tmp_buf, const int64_t buff_size, int64_t& pos, const ObString& value_string,
+    const int64_t fmt_enum, const int64_t start_pos, const int64_t print_value_len)
+{
+  int ret = common::OB_SUCCESS;
+  ObString print_value_string;
+  if (OB_UNLIKELY(print_value_len < 0)) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("print_value_len should not less then zero", K(ret), K(print_value_len));
+  } else {
+    if (start_pos > 1) {
+      if (start_pos > value_string.length()) {
+        // empty
+      } else {
+        print_value_string.assign_ptr(
+            value_string.ptr() + start_pos - 1, MIN((value_string.length() - start_pos), print_value_len));
+      }
+    } else if (start_pos < 0) {
+      if (-start_pos > value_string.length()) {
+        print_value_string.assign_ptr(value_string.ptr(), MIN((value_string.length()), print_value_len));
+      } else {
+        print_value_string.assign_ptr(
+            value_string.ptr() + value_string.length() + start_pos, MIN((-start_pos), print_value_len));
+      }
+    } else {
+      print_value_string.assign_ptr(value_string.ptr(), MIN((value_string.length()), print_value_len));
+    }
+
+    if (ReturnFormat::RF_ASCII == fmt_enum) {
+      for (int64_t i = 0; i < print_value_string.length() && OB_SUCC(ret); ++i) {
+        if (isprint(print_value_string[i])) {
+          if (OB_FAIL(databuff_printf(tmp_buf, buff_size, pos, "%c,", print_value_string[i]))) {
+            LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+          }
+        } else {
+          if (OB_FAIL(
+                  databuff_printf(tmp_buf, buff_size, pos, "%x,", (unsigned)(unsigned char)print_value_string[i]))) {
+            LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+          }
+        }
+      }
+    } else {  //%u, %x, %o
+      char fmt_str[4] = {0};
+      fmt_str[0] = '%';
+      fmt_str[1] = (ReturnFormat::RF_HEX == fmt_enum ? 'x' : (ReturnFormat::RF_OCT == fmt_enum ? 'o' : 'u'));
+      fmt_str[2] = ',';
+
+      for (int64_t i = 0; i < print_value_string.length() && OB_SUCC(ret); ++i) {
+        if (OB_FAIL(
+                databuff_printf(tmp_buf, buff_size, pos, fmt_str, (unsigned)(unsigned char)print_value_string[i]))) {
+          LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+        }
+      }
+    }
+  }
+
+  if (OB_SUCC(ret)) {
+    pos -= 1;
+    LOG_DEBUG("succ to print_value",
+        K(value_string),
+        K(print_value_string),
+        K(fmt_enum),
+        K(start_pos),
+        K(print_value_len),
+        K(pos));
+  }
+  return ret;
+}
+
+int ObExprFuncDump::calc_result_typeN(
+    ObExprResType& type, ObExprResType* types, int64_t param_num, common::ObExprTypeCtx& type_ctx) const
+{
+  int ret = OB_SUCCESS;
+  CK(NULL != type_ctx.get_session());
+  CK(NULL != types);
+  CK(param_num >= 1);
+  if (OB_FAIL(ret)) {
+  } else if (lib::is_oracle_mode()) {
+    if (OB_UNLIKELY(types[0].is_clob() || types[0].is_blob())) {
+      ret = OB_ERR_INVALID_TYPE_FOR_OP;
+      LOG_WARN("type not support now", K(param_num), K(types[0].get_type()), K(ret));
+    } else if (OB_UNLIKELY(param_num > 4)) {
+      ret = OB_NOT_SUPPORTED;
+      LOG_WARN("too many argument not support now", K(param_num), K(ret));
+      LOG_USER_ERROR(OB_NOT_SUPPORTED, "too many argument");
+    } else if (types[0].is_null()) {
+      type.set_null();
+    } else {
+      type.set_varchar();
+      type.set_collation_level(common::CS_LEVEL_COERCIBLE);
+      if (!type_ctx.get_session()->use_static_typing_engine()) {
+        type.set_default_collation_type();
+      } else {
+        type.set_collation_type(type_ctx.get_coll_type());
+      }
+      type.set_length(MAX_DUMP_BUFFER_SIZE);
+      const common::ObLengthSemantics default_length_semantics =
+          (OB_NOT_NULL(type_ctx.get_session()) ? type_ctx.get_session()->get_actual_nls_length_semantics()
+                                               : common::LS_BYTE);
+      type.set_length_semantics(default_length_semantics);
+      if (param_num > 1) {
+        types[1].set_calc_type(ObNumberType);
+      }
+      if (param_num > 2) {
+        types[2].set_calc_type(ObNumberType);
+      }
+      if (param_num > 3) {
+        types[3].set_calc_type(ObNumberType);
+      }
+    }
+  } else {
+    if (OB_UNLIKELY(param_num > 1)) {
+      ret = OB_NOT_SUPPORTED;
+      LOG_WARN("too many argument not support now", K(param_num), K(ret));
+    } else if (OB_UNLIKELY((!types[0].is_number() && !types[0].is_null())) &&
+               !type_ctx.get_session()->use_static_typing_engine()) {
+      ret = OB_NOT_SUPPORTED;
+      LOG_WARN("type not support now", K(param_num), K(types[0].get_type()), K(ret));
+    } else if (types[0].is_null()) {
+      type.set_null();
+    } else {
+      type.set_varchar();
+      type.set_collation_level(common::CS_LEVEL_COERCIBLE);
+      type.set_default_collation_type();
+      type.set_length(types[0].get_length());
+    }
+  }
+  return ret;
+}
+
+int ObExprFuncDump::calc_params(const common::ObObj* objs, const int64_t param_num, int64_t& fmt_enum,
+    int64_t& start_pos, int64_t& print_value_len) const
+{
+  int ret = OB_SUCCESS;
+  fmt_enum = ReturnFormat::RF_DEC;  // default
+  start_pos = 0;
+  print_value_len = MAX_DUMP_BUFFER_SIZE;
+
+  if (param_num > 1) {
+    int64_t fmt_param = 0;
+    if (objs[1].is_null()) {
+      fmt_param = ReturnFormat::RF_DEC;
+    } else if (OB_FAIL(objs[1].get_number().extract_valid_int64_with_trunc(fmt_param))) {
+      LOG_WARN("failed to extract_valid_int64_with_trunc", K(ret), "number", objs[1].get_number());
+    } else {
+      if (fmt_param < ReturnFormat::RF_OB_SEPC || fmt_param >= ReturnFormat::RF_ASCII) {
+        fmt_enum = ReturnFormat::RF_ASCII;
+      } else if (ReturnFormat::RF_OB_SEPC == fmt_param || ReturnFormat::RF_OCT == fmt_param ||
+                 ReturnFormat::RF_DEC == fmt_param || ReturnFormat::RF_HEX == fmt_param) {
+        fmt_enum = fmt_param;
+      } else {
+        fmt_enum = ReturnFormat::RF_DEC;  // default
+      }
+    }
+  }
+
+  if (OB_SUCC(ret) && param_num > 2) {
+    if (OB_FAIL(objs[2].get_number().extract_valid_int64_with_trunc(start_pos))) {
+      LOG_WARN("failed to extract_valid_int64_with_trunc", K(ret), "number", objs[2].get_number());
+    }
+  }
+
+  if (OB_SUCC(ret) && param_num > 3) {
+    if (OB_FAIL(objs[3].get_number().extract_valid_int64_with_trunc(print_value_len))) {
+      LOG_WARN("failed to extract_valid_int64_with_trunc", K(ret), "number", objs[3].get_number());
+    } else {
+      print_value_len = std::abs(print_value_len);
+      if (0 == print_value_len) {
+        print_value_len = MAX_DUMP_BUFFER_SIZE;
+      }
+    }
+  }
+
+  LOG_DEBUG("finish calc_params", K(ret), K(param_num), K(fmt_enum), K(start_pos), K(print_value_len));
+  return ret;
+}
+
+int ObExprFuncDump::calc_number(const common::ObObj& input, const int64_t fmt_enum, int64_t& start_pos,
+    int64_t& print_value_len, common::ObString& output) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_UNLIKELY(!input.is_number() && !input.is_number_float())) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("only number arrive here", K(input), K(ret));
+  } else {
+    const number::ObNumber nmb = input.get_number();
+    char* tmp_buf = output.ptr();
+    int64_t buff_size = output.size();
+    int64_t pos = output.length();
+    if (OB_FAIL(databuff_printf(tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), nmb.get_deep_copy_size()))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(nmb));
+    } else if (ReturnFormat::RF_OB_SEPC == fmt_enum) {
+      if (OB_FAIL(databuff_print_obj(tmp_buf, buff_size, pos, nmb))) {
+        LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+      }
+    } else {
+      const int64_t MAX_DATATYPE_VALUE_SIZE = number::ObNumber::MAX_BYTE_LEN;
+      char tmp_value_buf[MAX_DATATYPE_VALUE_SIZE] = {0};
+      int64_t value_pos = 0;
+      const uint32_t tmp_desc_value = nmb.get_desc_value();
+      MEMCPY(tmp_value_buf, &tmp_desc_value, sizeof(uint32_t));
+      MEMCPY(tmp_value_buf + sizeof(uint32_t), nmb.get_digits(), sizeof(uint32_t) * nmb.get_length());
+      value_pos = sizeof(uint32_t) + sizeof(uint32_t) * nmb.get_length();
+      ObString value_string(value_pos, tmp_value_buf);
+
+      if (OB_FAIL(print_value(tmp_buf, buff_size, pos, value_string, fmt_enum, start_pos, print_value_len))) {
+        LOG_WARN("failed to print_value", K(ret), K(pos), K(fmt_enum));
+      }
+    }
+
+    if (OB_SUCC(ret)) {
+      output.set_length(pos);
+      LOG_DEBUG("succ to dump number", K(input), K(fmt_enum), K(output));
+    }
+  }
+  return ret;
+}
+
+int ObExprFuncDump::calc_otimestamp(const common::ObObj& input, const int64_t fmt_enum, int64_t& start_pos,
+    int64_t& print_value_len, common::ObString& output) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_UNLIKELY(!input.is_otimestamp_type() && !input.is_datetime())) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("only otimestamp arrive here", K(input), K(ret));
+  } else {
+    ObOTimestampData odata = input.get_otimestamp_value();
+    char* tmp_buf = output.ptr();
+    int64_t buff_size = output.size();
+    int64_t pos = output.length();
+    if (input.is_datetime() &&
+        OB_FAIL(databuff_printf(tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), sizeof(int64_t)))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(input));
+    } else if (input.is_otimestamp_type() &&
+               OB_FAIL(databuff_printf(
+                   tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), input.get_otimestamp_store_size()))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(input));
+    } else if (ReturnFormat::RF_OB_SEPC == fmt_enum) {
+      if (input.is_datetime()) {
+        odata.time_ctx_.desc_ = 0;
+      } else if (!input.is_timestamp_tz()) {
+        odata.time_ctx_.tz_desc_ = 0;
+      }
+      if (OB_FAIL(databuff_print_obj(tmp_buf, buff_size, pos, odata))) {
+        LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+      }
+    } else {
+      const int64_t MAX_DATATYPE_VALUE_SIZE = sizeof(ObOTimestampData);
+      char tmp_value_buf[MAX_DATATYPE_VALUE_SIZE] = {0};
+      int64_t value_pos = 0;
+      if (input.is_timestamp_tz()) {
+        MEMCPY(tmp_value_buf, &odata.time_ctx_.desc_, sizeof(uint32_t));
+        value_pos = sizeof(uint32_t);
+      } else if (!input.is_datetime()) {
+        const uint16_t tail_nsec = odata.time_ctx_.tail_nsec_;
+        MEMCPY(tmp_value_buf, &tail_nsec, sizeof(uint16_t));
+        value_pos = sizeof(uint16_t);
+      }
+      MEMCPY(tmp_value_buf + value_pos, &odata.time_us_, sizeof(int64_t));
+      value_pos += sizeof(int64_t);
+      ObString value_string(value_pos, tmp_value_buf);
+
+      if (OB_FAIL(print_value(tmp_buf, buff_size, pos, value_string, fmt_enum, start_pos, print_value_len))) {
+        LOG_WARN("failed to print_value", K(ret), K(pos), K(fmt_enum));
+      }
+    }
+    if (OB_SUCC(ret)) {
+      output.set_length(pos);
+      LOG_DEBUG("succ to dump otimestamp", K(input), K(fmt_enum), K(output));
+    }
+  }
+
+  return ret;
+}
+
+int ObExprFuncDump::calc_string(const common::ObObj& input, const int64_t fmt_enum, int64_t& start_pos,
+    int64_t& print_value_len, common::ObString& output) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_UNLIKELY(
+          !ob_is_string_type(input.get_type()) && !ob_is_raw(input.get_type()) && !ob_is_rowid_tc(input.get_type()))) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("only string type arrive here", K(input), K(ret));
+  } else {
+    char* tmp_buf = output.ptr();
+    int64_t buff_size = output.size();
+    int64_t pos = output.length();
+
+    if (OB_FAIL(databuff_printf(tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), input.get_val_len()))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(input));
+    } else if (OB_FAIL(
+                   print_value(tmp_buf, buff_size, pos, input.get_string(), fmt_enum, start_pos, print_value_len))) {
+      LOG_WARN("failed to print_value", K(ret), K(pos), K(fmt_enum));
+    } else {
+      output.set_length(pos);
+      LOG_DEBUG("succ to dump string", K(input), K(fmt_enum), K(output));
+    }
+  }
+
+  return ret;
+}
+
+int ObExprFuncDump::calc_double(const common::ObObj& input, const int64_t fmt_enum, int64_t& start_pos,
+    int64_t& print_value_len, common::ObString& output) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_UNLIKELY(!input.is_float() && !input.is_double())) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("only float/double type arrive here", K(input), K(ret));
+  } else {
+    char* tmp_buf = output.ptr();
+    int64_t buff_size = output.size();
+    int64_t pos = output.length();
+    const int64_t print_size = (input.is_float() ? sizeof(float) : sizeof(double));
+
+    if (OB_FAIL(databuff_printf(tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), print_size))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(input));
+    } else {
+      const int64_t MAX_DATATYPE_VALUE_SIZE = sizeof(double);
+      char tmp_value_buf[MAX_DATATYPE_VALUE_SIZE] = {0};
+      int64_t value_pos = 0;
+      if (input.is_double()) {
+        const double tmp_value = input.get_double();
+        MEMCPY(tmp_value_buf, &tmp_value, sizeof(double));
+        value_pos = sizeof(double);
+      } else {
+        const float tmp_value = input.get_float();
+        MEMCPY(tmp_value_buf, &tmp_value, sizeof(float));
+        value_pos = sizeof(float);
+      }
+      ObString value_string(value_pos, tmp_value_buf);
+
+      if (OB_FAIL(print_value(tmp_buf, buff_size, pos, value_string, fmt_enum, start_pos, print_value_len))) {
+        LOG_WARN("failed to print_value", K(ret), K(pos), K(fmt_enum));
+      }
+    }
+
+    if (OB_SUCC(ret)) {
+      output.set_length(pos);
+      LOG_DEBUG("succ to dump float/double", K(input), K(fmt_enum), K(output));
+    }
+  }
+  return ret;
+}
+
+int ObExprFuncDump::calc_interval(const common::ObObj& input, const int64_t fmt_enum, int64_t& start_pos,
+    int64_t& print_value_len, common::ObString& output) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_UNLIKELY(!input.is_interval_ds() && !input.is_interval_ym())) {
+    ret = OB_ERR_UNEXPECTED;
+    LOG_WARN("only interval arrive here", K(input), K(ret));
+  } else {
+    char* tmp_buf = output.ptr();
+    int64_t buff_size = output.size();
+    int64_t pos = output.length();
+    const ObIntervalDSValue tmp_interval_ds_value = input.get_interval_ds();
+    const ObIntervalYMValue tmp_interval_ym_value = input.get_interval_ym();
+    if (OB_FAIL(databuff_printf(
+            tmp_buf, buff_size, pos, CONST_HEADER, input.get_type(), input.get_interval_store_size()))) {
+      LOG_WARN("failed to databuff_printf", K(ret), K(input));
+    } else if (ReturnFormat::RF_OB_SEPC == fmt_enum) {
+      if (input.is_interval_ds()) {
+        if (OB_FAIL(databuff_print_obj(tmp_buf, buff_size, pos, (tmp_interval_ds_value)))) {
+          LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+        }
+      } else {
+        if (OB_FAIL(databuff_print_obj(tmp_buf, buff_size, pos, (tmp_interval_ym_value)))) {
+          LOG_WARN("failed to databuff_printf", K(ret), K(pos));
+        }
+      }
+    } else {
+      const int64_t MAX_DATATYPE_VALUE_SIZE = MAX(sizeof(ObIntervalDSValue), sizeof(ObIntervalYMValue));
+      char tmp_value_buf[MAX_DATATYPE_VALUE_SIZE] = {0};
+      int64_t value_pos = 0;
+      if (input.is_interval_ds()) {
+        MEMCPY(tmp_value_buf, &tmp_interval_ds_value.fractional_second_, sizeof(int32_t));
+        MEMCPY(tmp_value_buf + sizeof(int32_t), &tmp_interval_ds_value.nsecond_, sizeof(int64_t));
+        value_pos = sizeof(int32_t) + sizeof(int64_t);
+      } else {
+        MEMCPY(tmp_value_buf, &tmp_interval_ym_value.nmonth_, sizeof(int64_t));
+        value_pos = sizeof(int64_t);
+      }
+      ObString value_string(value_pos, tmp_value_buf);
+
+      if (OB_FAIL(print_value(tmp_buf, buff_size, pos, value_string, fmt_enum, start_pos, print_value_len))) {
+        LOG_WARN("failed to print_value", K(ret), K(pos), K(fmt_enum));
+      }
+    }
+
+    if (OB_SUCC(ret)) {
+      output.set_length(pos);
+      LOG_DEBUG("succ to dump interval", K(input), K(fmt_enum), K(output));
+    }
+  }
+
+  return ret;
+}
+
+int ObExprFuncDump::calc_resultN(
+    common::ObObj& result, const common::ObObj* objs, int64_t param_num, common::ObExprCtx& expr_ctx) const
+{
+  int ret = OB_SUCCESS;
+  if (OB_ISNULL(expr_ctx.calc_buf_)) {
+    ret = OB_NOT_INIT;
+    LOG_WARN("varchar buffer not init", K(ret));
+  } else if (lib::is_oracle_mode()) {
+    int64_t fmt_enum = 0;
+    int64_t start_pos = 0;
+    int64_t print_value_len = 0;
+
+    if (objs[0].is_null_oracle()) {
+      result.set_null();
+    } else if (OB_FAIL(calc_params(objs, param_num, fmt_enum, start_pos, print_value_len))) {
+      LOG_WARN("varchar buffer not init", K(ret));
+    } else {
+      char tmp_buf[MAX_DUMP_BUFFER_SIZE] = {0};
+      int64_t pos = 0;
+      ObString output(MAX_DUMP_BUFFER_SIZE, pos, tmp_buf);
+      switch (objs[0].get_type()) {
+        case ObNumberType:
+        case ObNumberFloatType: {
+          if (OB_FAIL(calc_number(objs[0], fmt_enum, start_pos, print_value_len, output))) {
+            LOG_WARN("fail to calc_number", K(ret));
+          }
+          break;
+        }
+        case ObDateTimeType:
+        case ObTimestampTZType:
+        case ObTimestampLTZType:
+        case ObTimestampNanoType: {
+          if (OB_FAIL(calc_otimestamp(objs[0], fmt_enum, start_pos, print_value_len, output))) {
+            LOG_WARN("fail to calc_otimestamp", K(ret));
+          }
+          break;
+        }
+        case ObFloatType:
+        case ObDoubleType: {
+          if (OB_FAIL(calc_double(objs[0], fmt_enum, start_pos, print_value_len, output))) {
+            LOG_WARN("fail to calc_double", K(ret));
+          }
+          break;
+        }
+        case ObIntervalYMType:
+        case ObIntervalDSType: {
+          if (OB_FAIL(calc_interval(objs[0], fmt_enum, start_pos, print_value_len, output))) {
+            LOG_WARN("fail to calc_interval", K(ret));
+          }
+          break;
+        }
+        case ObRawType:
+        case ObCharType:
+        case ObVarcharType:
+        case ObNCharType:
+        case ObNVarchar2Type:
+        case ObURowIDType: {
+          if (OB_FAIL(calc_string(objs[0], fmt_enum, start_pos, print_value_len, output))) {
+            LOG_WARN("fail to calc_interval", K(ret));
+          }
+          break;
+        }
+        default: {
+          ret = OB_NOT_SUPPORTED;
+          LOG_WARN("type not support now", K(objs[0].get_type()), K(ret));
+        } break;
+      }
+
+      if (OB_SUCC(ret)) {
+        ObString dst_str;
+        if (OB_FAIL(ob_write_string(*expr_ctx.calc_buf_, output, dst_str))) {
+          LOG_WARN("copy string fail", K(ret), K(output));
+        } else {
+          result.set_varchar(dst_str);
+          result.set_collation(result_type_);
+        }
+      }
+    }
+  } else {
+    switch (objs[0].get_type()) {
+      case ObNumberType: {
+        number::ObNumber nmb = objs[0].get_number();
+        const char* nmb_str = to_cstring(nmb);
+        ObString src_str(0, (int32_t)strlen(nmb_str), const_cast<char*>(nmb_str));
+        ObString dst_str;
+        if (OB_FAIL(ob_write_string(*expr_ctx.calc_buf_, src_str, dst_str))) {
+          LOG_WARN("copy string fail", K(ret), K(src_str));
+        } else {
+          result.set_varchar(dst_str);
+          result.set_collation(result_type_);
+        }
+        break;
+      }
+      case ObNullType: {
+        result.set_null();
+      } break;
+      default: {
+        ret = OB_NOT_SUPPORTED;
+        LOG_WARN("type not support now", K(objs[0].get_type()), K(ret));
+      } break;
+    }
+  }
+  return ret;
+}
+
+static int dump_ob_spec(
+    char* buf, int64_t buf_len, int64_t& buf_pos, bool& dumped, const ObExpr& expr, const ObDatum& datum)
+{
+  dumped = true;
+  int ret = OB_SUCCESS;
+  switch (expr.datum_meta_.type_) {
+    case ObNumberType:
+    case ObNumberFloatType: {
+      number::ObNumber nmb(datum.get_number());
+      OZ(databuff_print_obj(buf, buf_len, buf_pos, nmb));
+      break;
+    }
+    case ObDateTimeType: {
+      OZ(databuff_print_obj(
+          buf, buf_len, buf_pos, ObOTimestampData(datum.get_datetime(), ObOTimestampData::UnionTZCtx())));
+      break;
+    }
+
+    case ObTimestampTZType: {
+      OZ(databuff_print_obj(buf, buf_len, buf_pos, datum.get_otimestamp_tz()));
+      break;
+    }
+
+    case ObTimestampLTZType:
+    case ObTimestampNanoType: {
+      OZ(databuff_print_obj(buf, buf_len, buf_pos, datum.get_otimestamp_tiny()));
+      break;
+    }
+    case ObIntervalYMType: {
+      const ObIntervalYMValue tmp_interval_ym_value(datum.get_interval_ym());
+      OZ(databuff_print_obj(buf, buf_len, buf_pos, tmp_interval_ym_value));
+      break;
+    }
+    case ObIntervalDSType: {
+      OZ(databuff_print_obj(buf, buf_len, buf_pos, datum.get_interval_ds()));
+      break;
+    }
+    default: {
+      dumped = false;
+    }
+  }
+  return ret;
+}
+
+int ObExprFuncDump::cg_expr(ObExprCGCtx&, const ObRawExpr&, ObExpr& rt_expr) const
+{
+  int ret = OB_SUCCESS;
+  CK(rt_expr.arg_cnt_ >= 1 && rt_expr.arg_cnt_ <= 4);
+  rt_expr.eval_func_ = &ObExprFuncDump::eval_dump;
+  return ret;
+}
+
+int ObExprFuncDump::eval_dump(const ObExpr& expr, ObEvalCtx& ctx, ObDatum& expr_datum)
+{
+  int ret = OB_SUCCESS;
+  if (is_oracle_mode()) {
+    ObDatum* input = NULL;
+    ObDatum* fmt = NULL;
+    ObDatum* pos = NULL;
+    ObDatum* len = NULL;
+    if (OB_FAIL(expr.eval_param_value(ctx, input, fmt, pos, len))) {
+      LOG_WARN("evaluate parameters failed", K(ret));
+    } else if (input->is_null()) {
+      expr_datum.set_null();
+    } else {
+      int64_t fmt_val = ReturnFormat::RF_DEC;  // default
+      int64_t pos_val = 1;
+      int64_t len_val = input->len_;
+
+      if (OB_FAIL(ObExprUtil::get_int_param_val(fmt, fmt_val)) ||
+          OB_FAIL(ObExprUtil::get_int_param_val(pos, pos_val)) ||
+          OB_FAIL(ObExprUtil::get_int_param_val(len, len_val))) {
+        LOG_WARN("get int parameter value failed", K(ret));
+      } else {
+        // parameter process same with ObExprFuncDump::calc_params
+        if (fmt_val < ReturnFormat::RF_OB_SEPC || fmt_val >= ReturnFormat::RF_ASCII) {
+          fmt_val = ReturnFormat::RF_ASCII;
+        } else if (!(ReturnFormat::RF_OB_SEPC == fmt_val || ReturnFormat::RF_OCT == fmt_val ||
+                       ReturnFormat::RF_DEC == fmt_val || ReturnFormat::RF_HEX == fmt_val)) {
+          fmt_val = ReturnFormat::RF_DEC;  // default
+        }
+        len_val = std::abs(len_val);
+        if (0 == len_val) {
+          len_val = input->len_;
+        }
+
+        char buf[MAX_DUMP_BUFFER_SIZE] = {0};
+        int64_t buf_len = sizeof(buf);
+        int64_t buf_pos = 0;
+        bool dumped = false;
+        if (OB_FAIL(databuff_printf(buf,
+                buf_len,
+                buf_pos,
+                CONST_HEADER,
+                expr.args_[0]->datum_meta_.type_,
+                static_cast<int64_t>(input->len_)))) {
+          LOG_WARN("data buffer print fail", K(ret));
+        } else if (ReturnFormat::RF_OB_SEPC == fmt_val) {
+          if (OB_FAIL(dump_ob_spec(buf, buf_len, buf_pos, dumped, *expr.args_[0], *input))) {
+            LOG_WARN("dump ob spec failed", K(ret));
+          } else if (!dumped) {
+            // dump ob spec not supported,  fail back to ReturnFormat::RF_DEC
+            fmt_val = ReturnFormat::RF_DEC;
+          }
+        }
+
+        if (OB_SUCC(ret) && !dumped) {
+          if (OB_FAIL(
+                  print_value(buf, buf_len, buf_pos, ObString(input->len_, input->ptr_), fmt_val, pos_val, len_val))) {
+            LOG_WARN("print value failed", K(ret));
+          }
+        }
+
+        if (OB_SUCC(ret)) {
+          if (OB_FAIL(ObExprUtil::set_expr_ascii_result(expr, ctx, expr_datum, ObString(buf_pos, buf)))) {
+            LOG_WARN("set ASCII result failed", K(ret));
+          }
+        }
+      }
+    }
+  } else {
+    ObDatum* input = NULL;
+    if (OB_FAIL(expr.eval_param_value(ctx, input))) {
+      LOG_WARN("evaluate parameters failed", K(ret));
+    } else if (input->is_null()) {
+      expr_datum.set_null();
+    } else {
+      switch (expr.args_[0]->datum_meta_.type_) {
+        case ObNumberType: {
+          number::ObNumber nmb(input->get_number());
+          const char* nmb_str = to_cstring(nmb);
+          ObString src_str(0, (int32_t)strlen(nmb_str), const_cast<char*>(nmb_str));
+          if (OB_FAIL(ObExprUtil::set_expr_ascii_result(expr, ctx, expr_datum, src_str))) {
+            LOG_WARN("set ASCII result failed", K(ret));
+          }
+          break;
+        }
+        case ObNullType: {
+          expr_datum.set_null();
+        } break;
+        default: {
+          ret = OB_NOT_SUPPORTED;
+          LOG_WARN("type not support now", K(expr.args_[0]->datum_meta_.type_), K(ret));
+        } break;
+      }
+    }
+  }
+  return ret;
+}
+
+}  // namespace sql
+}  // namespace oceanbase