diff --git a/src/sql/ob_sql_utils.cpp b/src/sql/ob_sql_utils.cpp
index 6e9de1a027e38ee52a9bd9887920be48a4ed67c5..656a330c6454bbfc8e7af56c231053f0f494e6e0 100644
--- a/src/sql/ob_sql_utils.cpp
+++ b/src/sql/ob_sql_utils.cpp
@@ -1204,7 +1204,10 @@ int ObSQLUtils::check_and_convert_table_name(const ObCollationType cs_type, cons
   const char* name_str = name.ptr();
   const int64_t max_user_table_name_length =
       share::is_oracle_mode() ? OB_MAX_USER_TABLE_NAME_LENGTH_ORACLE : OB_MAX_USER_TABLE_NAME_LENGTH_MYSQL;
-  if (0 == name_len || name_len > (max_user_table_name_length * OB_MAX_CHAR_LEN) || OB_ISNULL(name_str)) {
+  const int64_t max_index_name_prefix_len = 30;
+  if (0 == name_len || (!is_index_table && (name_len > (max_user_table_name_length * OB_MAX_CHAR_LEN))) ||
+      (is_index_table && (name_len > (max_user_table_name_length * OB_MAX_CHAR_LEN + max_index_name_prefix_len))) ||
+      OB_ISNULL(name_str)) {
     ret = OB_WRONG_TABLE_NAME;
     LOG_USER_ERROR(OB_WRONG_TABLE_NAME, static_cast<int32_t>(name_len), name_str);
     LOG_WARN("incorrect table name", K(name), K(ret));
@@ -1279,14 +1282,21 @@ int ObSQLUtils::check_column_name(const ObCollationType cs_type, ObString& name)
   bool last_char_is_space = false;
   const char* end = name.ptr() + name.length();
   const char* name_str = name.ptr();
-  size_t name_char_len = 0;
+  size_t name_len = 0;  // char semantics for MySQL mode, and byte semantics for Oracle mode
+  size_t byte_length = 0;
+  int is_mb_char = 0;
   while (OB_SUCCESS == ret && name_str != end) {
     last_char_is_space = ObCharset::is_space(CS_TYPE_UTF8MB4_GENERAL_CI, *name_str);
     if (ObCharset::usemb(CS_TYPE_UTF8MB4_GENERAL_CI)) {
-      int char_len = ObCharset::is_mbchar(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end);
-      if (char_len) {
-        name_str += char_len;
-        name_char_len++;
+      is_mb_char = ObCharset::is_mbchar(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end);
+      if (is_mb_char) {
+        byte_length = ObCharset::charpos(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end - name_str, 1);
+        name_str += byte_length;
+        if (share::is_mysql_mode()) {
+          name_len++;
+        } else {
+          name_len += byte_length;
+        }
         continue;
       }
     }
@@ -1295,7 +1305,7 @@ int ObSQLUtils::check_column_name(const ObCollationType cs_type, ObString& name)
       ret = OB_WRONG_COLUMN_NAME;
     } else {
       name_str++;
-      name_char_len++;
+      name_len++;
     }
   }
 
@@ -1304,10 +1314,10 @@ int ObSQLUtils::check_column_name(const ObCollationType cs_type, ObString& name)
       ret = OB_WRONG_COLUMN_NAME;
       LOG_USER_ERROR(OB_WRONG_COLUMN_NAME, name.length(), name.ptr());
       LOG_WARN("incorrect column name", K(name), K(ret));
-    } else if (name_char_len > static_cast<size_t>(OB_MAX_COLUMN_NAME_LENGTH)) {
+    } else if (name_len > static_cast<size_t>(OB_MAX_COLUMN_NAME_LENGTH)) {
       ret = OB_ERR_TOO_LONG_IDENT;
       LOG_USER_ERROR(OB_ERR_TOO_LONG_IDENT, name.length(), name.ptr());
-      LOG_WARN("column name is too long", K(name), K(ret));
+      LOG_WARN("column name is too long", K(ret), K(name), K(name_len));
     }
   }
   return ret;
@@ -1345,33 +1355,39 @@ int ObSQLUtils::check_ident_name(
   bool last_char_is_space = false;
   const char* end = name.ptr() + name.length();
   const char* name_str = name.ptr();
-  size_t name_char_len = 0;
+  size_t name_len = 0;  // char semantics for MySQL mode, and byte semantics for Oracle mode
+  size_t byte_length = 0;
+  int is_mb_char = 0;
   while (OB_SUCCESS == ret && NULL != name_str && name_str != end) {
     last_char_is_space = ObCharset::is_space(CS_TYPE_UTF8MB4_GENERAL_CI, *name_str);
     if (ObCharset::usemb(CS_TYPE_UTF8MB4_GENERAL_CI)) {
-      int char_len = ObCharset::is_mbchar(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end);
-      if (char_len) {
-        name_str += char_len;
-        name_char_len++;
+      is_mb_char = ObCharset::is_mbchar(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end);
+      if (is_mb_char) {
+        byte_length = ObCharset::charpos(CS_TYPE_UTF8MB4_GENERAL_CI, name_str, end - name_str, 1);
+        name_str += byte_length;
+        if (share::is_mysql_mode()) {
+          name_len++;
+        } else {
+          name_len += byte_length;
+        }
         continue;
       }
     }
-
     if (check_for_path_char && ('/' == *name_str || '\\' == *name_str || '~' == *name_str || '.' == *name_str)) {
       ret = OB_ERR_WRONG_IDENT_NAME;
       LOG_WARN("Incorrect database name", K(name), K(ret));
     } else {
       name_str++;
-      name_char_len++;
+      name_len++;
     }
   }
   if (OB_SUCC(ret)) {
     if (last_char_is_space) {
       ret = OB_ERR_WRONG_IDENT_NAME;
       LOG_WARN("incorrect ident name", K(name), K(ret));
-    } else if (name_char_len > static_cast<size_t>(max_ident_len)) {
+    } else if (name_len > static_cast<size_t>(max_ident_len)) {
       ret = OB_ERR_TOO_LONG_IDENT;
-      LOG_WARN("ident name is too long", K(name), K(ret));
+      LOG_WARN("ident name is too long", K(ret), K(name), K(name.length()), K(name_len));
     }
   }
   return ret;
diff --git a/src/sql/resolver/ddl/ob_create_table_resolver.cpp b/src/sql/resolver/ddl/ob_create_table_resolver.cpp
index 14c0ea8cd40ccfbaebd012e1d6935af6be670c2b..8c64302a3901edb79002159ffd4ced8ad41e736c 100644
--- a/src/sql/resolver/ddl/ob_create_table_resolver.cpp
+++ b/src/sql/resolver/ddl/ob_create_table_resolver.cpp
@@ -946,9 +946,6 @@ int ObCreateTableResolver::check_column_name_duplicate(const ParseNode* node)
           if (OB_ISNULL(name_node)) {
             ret = OB_ERR_UNEXPECTED;
             LOG_WARN("name node can not be null", K(ret));
-          } else if (name_node->str_len_ > OB_MAX_COLUMN_NAME_LENGTH) {
-            ret = OB_ERR_TOO_LONG_IDENT;
-            LOG_USER_ERROR(OB_ERR_TOO_LONG_IDENT, (int)name_node->str_len_, name_node->str_value_);
           } else if (0 == name_node->str_len_) {
             ret = OB_WRONG_COLUMN_NAME;
             LOG_USER_ERROR(OB_WRONG_COLUMN_NAME, (int)name_node->str_len_, name_node->str_value_);
@@ -2461,11 +2458,14 @@ int ObCreateTableResolver::resolve_index_name(
   }
 
   if (OB_SUCC(ret)) {
-    const int64_t max_user_table_name_length =
-        share::is_oracle_mode() ? OB_MAX_USER_TABLE_NAME_LENGTH_ORACLE : OB_MAX_USER_TABLE_NAME_LENGTH_MYSQL;
-    if (index_name_.length() > max_user_table_name_length) {
-      ret = OB_ERR_TOO_LONG_IDENT;
-      LOG_USER_ERROR(OB_ERR_TOO_LONG_IDENT, index_name_.length(), index_name_.ptr());
+    ObCollationType cs_type = CS_TYPE_INVALID;
+    if (OB_UNLIKELY(NULL == session_info_)) {
+      ret = OB_ERR_UNEXPECTED;
+      LOG_WARN("session if NULL", K(ret));
+    } else if (OB_FAIL(session_info_->get_collation_connection(cs_type))) {
+      LOG_WARN("fail to get collation connection", K(ret));
+    } else if (OB_FAIL(ObSQLUtils::check_index_name(cs_type, index_name_))) {
+      LOG_WARN("fail to check index name", K(ret), K(index_name_));
     }
   }
 
diff --git a/src/sql/resolver/ddl/ob_create_view_resolver.cpp b/src/sql/resolver/ddl/ob_create_view_resolver.cpp
index 6bcf39396363c407291717ad7ed059ca3cd82b1a..3381055931ee3bfe85e5fdfe560ee2bcf3318ca1 100644
--- a/src/sql/resolver/ddl/ob_create_view_resolver.cpp
+++ b/src/sql/resolver/ddl/ob_create_view_resolver.cpp
@@ -117,11 +117,13 @@ int ObCreateViewResolver::resolve(const ParseNode& parse_tree)
           }
 
           if (OB_SUCC(ret)) {
-            const int64_t max_user_table_name_length =
-                share::is_oracle_mode() ? OB_MAX_USER_TABLE_NAME_LENGTH_ORACLE : OB_MAX_USER_TABLE_NAME_LENGTH_MYSQL;
-            if (view_name.length() > max_user_table_name_length) {
-              ret = OB_ERR_TOO_LONG_IDENT;
-              LOG_USER_ERROR(OB_ERR_TOO_LONG_IDENT, view_name.length(), view_name.ptr());
+            ObNameCaseMode mode = OB_NAME_CASE_INVALID;
+            bool perserve_lettercase = false;
+            if (OB_FAIL(session_info_->get_name_case_mode(mode))) {
+              LOG_WARN("fail to get name case mode", K(ret), K(mode));
+            } else if (FALSE_IT(perserve_lettercase = share::is_oracle_mode() ? true : (mode != OB_LOWERCASE_AND_INSENSITIVE))) {
+            } else if (OB_FAIL(ObSQLUtils::check_and_convert_table_name(CS_TYPE_UTF8MB4_GENERAL_CI, perserve_lettercase, view_name))) {
+              LOG_WARN("fail to check and convert view_name", K(ret), K(view_name));
             } else {
               table_schema.set_tenant_id(session_info_->get_effective_tenant_id());
               table_schema.set_tablegroup_id(combine_id(OB_SYS_TENANT_ID, OB_SYS_TABLEGROUP_ID));
@@ -304,8 +306,6 @@ int ObCreateViewResolver::resolve(const ParseNode& parse_tree)
               // do nothing
             }
           }
-
-          // 检查 mysql 模式下列名定义
           if (share::is_mysql_mode() && !(is_sync_ddl_user && session_info_->is_inner())) {
             if (OB_FAIL(ret)) {
               // do nothing
diff --git a/src/sql/resolver/ddl/ob_ddl_resolver.cpp b/src/sql/resolver/ddl/ob_ddl_resolver.cpp
index 1b5d16f2410112026747e4e513a9d4efb42e2561..f8b70d437c805d4e43360a8d0a67eed828458f9c 100644
--- a/src/sql/resolver/ddl/ob_ddl_resolver.cpp
+++ b/src/sql/resolver/ddl/ob_ddl_resolver.cpp
@@ -1799,7 +1799,7 @@ int ObDDLResolver::resolve_column_name(common::ObString& col_name, ParseNode* no
     col_name.assign_ptr(node->str_value_, node->str_len_);
     int32_t name_length = col_name.length();
     const char* name_ptr = col_name.ptr();
-    if (name_length > OB_MAX_COLUMN_NAME_LENGTH) {
+    if (name_length > OB_MAX_COLUMN_NAME_LENGTH * OB_MAX_CHAR_LEN) {
       ret = OB_ERR_TOO_LONG_IDENT;
       _SQL_RESV_LOG(
           WARN, "identifier name '%.*s' is too long, ret=%d", static_cast<int32_t>(name_length), name_ptr, ret);
diff --git a/src/sql/session/ob_basic_session_info.cpp b/src/sql/session/ob_basic_session_info.cpp
index 6244029fcc80c7908d957496586f8309f2097055..b0a580cc7d62a8f9e9a5f056dd9a0e2aa45cfa24 100644
--- a/src/sql/session/ob_basic_session_info.cpp
+++ b/src/sql/session/ob_basic_session_info.cpp
@@ -641,7 +641,7 @@ int ObBasicSessionInfo::set_default_database(
     const ObString& database_name, const ObCollationType coll_type /*= CS_TYPE_INVALID */)
 {
   int ret = OB_SUCCESS;
-  if (database_name.length() > OB_MAX_DATABASE_NAME_LENGTH) {
+  if (database_name.length() > OB_MAX_DATABASE_NAME_LENGTH * OB_MAX_CHAR_LEN) {
     ret = OB_INVALID_ARGUMENT_FOR_LENGTH;
     LOG_WARN("invalid length for database_name", K(database_name), K(ret));
   } else {
diff --git a/src/sql/session/ob_basic_session_info.h b/src/sql/session/ob_basic_session_info.h
index b1ba519343a31066184b185a04eacfe071b32232..de2341cc77f60927c0ae1a2be25f331279b2069e 100644
--- a/src/sql/session/ob_basic_session_info.h
+++ b/src/sql/session/ob_basic_session_info.h
@@ -1689,12 +1689,12 @@ protected:
     }
     ~MultiThreadData()
     {}
-    common::ObString user_name_;                                   // current user name
-    common::ObString host_name_;                                   // current user host name
-    common::ObString client_ip_;                                   // current user real client host name
-    common::ObString user_at_host_name_;                           // current user@host, for current_user()
-    common::ObString user_at_client_ip_;                           // current user@clientip, for user()
-    char database_name_[common::OB_MAX_DATABASE_NAME_BUF_LENGTH];  // default database
+    common::ObString user_name_;          // current user name
+    common::ObString host_name_;          // current user host name
+    common::ObString client_ip_;          // current user real client host name
+    common::ObString user_at_host_name_;  // current user@host, for current_user()
+    common::ObString user_at_client_ip_;  // current user@clientip, for user()
+    char database_name_[common::OB_MAX_DATABASE_NAME_BUF_LENGTH * OB_MAX_CHAR_LEN];  // default database
     common::ObAddr peer_addr_;
     common::ObAddr user_client_addr_;
     int64_t cur_query_buf_len_;