diff --git a/deps/oblib/src/lib/utility/ob_print_utils.h b/deps/oblib/src/lib/utility/ob_print_utils.h
index 239b0609c..8117a169a 100644
--- a/deps/oblib/src/lib/utility/ob_print_utils.h
+++ b/deps/oblib/src/lib/utility/ob_print_utils.h
@@ -147,11 +147,11 @@ public:
 class CStringBufMgr
 {
 public:
-  static const int BUF_SIZE = 8 * 1024;
-  static const int MIN_REST_SIZE = 1024;
+  static const int BUF_SIZE = 32 * 1024;
+  static const int MIN_SIZE = 12 * 1024;
   struct BufNode
   {
-    char buf_[BUF_SIZE];
+    char buf_[MIN_SIZE];
     int64_t level_;
     struct BufNode *next_;
   };
@@ -169,17 +169,19 @@ public:
   }
   void inc_level() { level_++; }
   void dec_level() { level_--; }
-  int64_t get_pos() { return pos_; }
-  void set_pos(int64_t pos)
+  void update_position(int64_t pos)
   {
     if (0 == level_) {
-      if (MIN_REST_SIZE > BUF_SIZE - pos) {
+      pos_ += pos;
+      if (MIN_SIZE > BUF_SIZE - pos_) {
         pos_ = 0;
-      } else {
-        pos_ = pos;
       }
     }
   }
+  int64_t get_buffer_len()
+  {
+    return 0 == level_ ? (BUF_SIZE - pos_) : MIN_SIZE;
+  }
   char *acquire()
   {
     char *buffer = NULL;
@@ -235,15 +237,14 @@ const char *to_cstring(const T &obj, const bool verbose)
   if (OB_ISNULL(buffer)) {
     LIB_LOG_RET(ERROR, OB_ALLOCATE_MEMORY_FAILED, "buffer is NULL");
   } else {
-    int64_t pos = mgr.get_pos();
-    const int64_t buf_len = CStringBufMgr::BUF_SIZE - pos;
+    const int64_t buf_len = mgr.get_buffer_len();
     str_len = obj.to_string(buffer, buf_len -1, verbose);
     if (str_len >= 0 && str_len < buf_len) {
       buffer[str_len] = '\0';
     } else {
       buffer[0] = '\0';
     }
-    mgr.set_pos(pos + str_len + 1);
+    mgr.update_position(str_len + 1);
   }
   mgr.try_clear_list();
   mgr.dec_level();
@@ -261,15 +262,14 @@ const char *to_cstring(const T &obj, FalseType)
   if (OB_ISNULL(buffer)) {
     LIB_LOG_RET(ERROR, OB_ALLOCATE_MEMORY_FAILED, "buffer is NULL");
   } else {
-    int64_t pos = mgr.get_pos();
-    const int64_t buf_len = CStringBufMgr::BUF_SIZE - pos;
+    const int64_t buf_len = mgr.get_buffer_len();
     str_len = to_string(obj, buffer, buf_len -1);
     if (str_len >= 0 && str_len < buf_len) {
       buffer[str_len] = '\0';
     } else {
       buffer[0] = '\0';
     }
-    mgr.set_pos(pos + str_len + 1);
+    mgr.update_position(str_len + 1);
   }
   mgr.try_clear_list();
   mgr.dec_level();
diff --git a/deps/oblib/unittest/lib/utility/test_print_utils.cpp b/deps/oblib/unittest/lib/utility/test_print_utils.cpp
index ebbce9f27..f5d4823cc 100644
--- a/deps/oblib/unittest/lib/utility/test_print_utils.cpp
+++ b/deps/oblib/unittest/lib/utility/test_print_utils.cpp
@@ -108,18 +108,12 @@ TEST(print_utility, to_cstring)
                to_cstring(*tuples[0]), to_cstring(*tuples[1]), to_cstring(*tuples[2]));
   _OB_LOG(INFO, "print tuple string, {%s}, {%s}, {%s}, {%s}, {%s}, {%s}, {%s}", to_cstring(*tuples[3]), to_cstring(*tuples[4]),
                to_cstring(*tuples[5]), to_cstring(*tuples[6]), to_cstring(*tuples[7]), to_cstring(*tuples[8]), to_cstring(*tuples[9]));
-  for (int i = 0; i < 10; ++i) {
-    int64_t pos = CStringBufMgr::get_thread_local_instance().get_pos();
-    _OB_LOG(INFO, "print tuple string, pos = %ld\n", pos);
-    to_cstring(*tuples[0]);
-  }
   // the performance of to_cstring when observer reach memory limit
   EventItem item;
   item.trigger_freq_ = 1;
   item.error_code_ = OB_ALLOCATE_MEMORY_FAILED;
   ::oceanbase::common::EventTable::instance().set_event(EventTable::EN_4, item);
-  int64_t pos = CStringBufMgr::get_thread_local_instance().get_pos();
-  _OB_LOG(INFO, "print tuple string, {%s}, pos = %ld\n", to_cstring(*tuples[0]), pos);
+  _OB_LOG(INFO, "print tuple string, {%s}\n", to_cstring(*tuples[0]));
 }
 
 int main(int argc, char **argv)
diff --git a/src/sql/engine/expr/ob_expr.h b/src/sql/engine/expr/ob_expr.h
index 46bc84116..3b4b6b84f 100644
--- a/src/sql/engine/expr/ob_expr.h
+++ b/src/sql/engine/expr/ob_expr.h
@@ -1120,8 +1120,7 @@ inline const char *get_vectorized_row_str(ObEvalCtx &eval_ctx,
   if (OB_ISNULL(buffer)) {
     LIB_LOG_RET(ERROR, OB_ALLOCATE_MEMORY_FAILED, "buffer is NULL");
   } else {
-    int64_t pos = mgr.get_pos();
-    const int64_t buf_len = CStringBufMgr::BUF_SIZE - pos;
+    const int64_t buf_len = mgr.get_buffer_len();
     databuff_printf(buffer, buf_len, str_len, "vectorized_rows(%ld)=", index);
     str_len += to_string(ROWEXPR2STR(eval_ctx, exprs), buffer + str_len, buf_len - str_len - 1);
     if (str_len >= 0 && str_len < buf_len) {
@@ -1129,6 +1128,7 @@ inline const char *get_vectorized_row_str(ObEvalCtx &eval_ctx,
     } else {
       buffer[0] = '\0';
     }
+    mgr.update_position(str_len + 1);
   }
   mgr.try_clear_list();
   mgr.dec_level();