Compatible with upstream components that do not support show trace

src/observer/virtual_table/ob_virtual_show_trace.cpp

@@ -269,7 +269,13 @@ int ObVirtualShowTrace::generate_span_info_tree()
       if (OB_ISNULL(show_trace_arr_.at(i))) {
         ret = OB_ERR_UNEXPECTED;
         SERVER_LOG(WARN, "record ptr is null", K(i));
-      } else if (show_trace_arr_.at(i)->data_.parent_span_id_ == "00000000-0000-0000-0000-000000000000") {
+      } else if (session_->get_last_flt_span_id().empty() &&
+            show_trace_arr_.at(i)->data_.parent_span_id_ == "00000000-0000-0000-0000-000000000000") {
+        found_root = true;
+        show_trace_arr_.at(i)->formatter_.level_ = depth;
+        OZ(root_arr.push_back(show_trace_arr_.at(i)));
+      } else if (!session_->get_last_flt_span_id().empty() &&
+          show_trace_arr_.at(i)->data_.parent_span_id_.compare(session_->get_last_flt_span_id()) == 0) {
         found_root = true;
         show_trace_arr_.at(i)->formatter_.level_ = depth;
         OZ(root_arr.push_back(show_trace_arr_.at(i)));
@@ -279,7 +285,7 @@ int ObVirtualShowTrace::generate_span_info_tree()
       // do nothing
     } else if (!found_root) {
       show_trace_arr_.reset();
-      LOG_TRACE("not found root span reset show trace");
+      LOG_INFO("not found root span reset show trace");
     } else {
       // recursively generate span tree
       for (int64_t i = 0; OB_SUCC(ret) && i < root_arr.count(); ++i) {

src/share/system_variable/ob_system_variable_init.cpp

@@ -1508,7 +1508,7 @@ static struct VarsInit{
       ObSysVars[111].name_ = "ob_enable_show_trace" ;
       ObSysVars[111].data_type_ = ObIntType ;
       ObSysVars[111].value_ = "0" ;
-      ObSysVars[111].flags_ = ObSysVarFlag::GLOBAL_SCOPE | ObSysVarFlag::SESSION_SCOPE | ObSysVarFlag::NEED_SERIALIZE ;
+      ObSysVars[111].flags_ = ObSysVarFlag::SESSION_SCOPE | ObSysVarFlag::NEED_SERIALIZE ;
       ObSysVars[111].id_ = SYS_VAR_OB_ENABLE_SHOW_TRACE ;
       cur_max_var_id = MAX(cur_max_var_id, static_cast<int64_t>(SYS_VAR_OB_ENABLE_SHOW_TRACE)) ;
       ObSysVarsIdToArrayIdx[SYS_VAR_OB_ENABLE_SHOW_TRACE] = 111 ;

src/share/system_variable/ob_system_variable_init.json

@@ -1489,7 +1489,7 @@
     "value": "0",
     "data_type": "bool",
     "info": "control whether use show trace",
-    "flags": "Global | SESSION | NEED_SERIALIZE",
+    "flags": "SESSION | NEED_SERIALIZE",
     "publish_version": "",
     "info_cn": "",
     "background_cn": "",

src/sql/monitor/flt/ob_flt_utils.cpp

@@ -54,13 +54,23 @@ namespace sql
   int ObFLTUtils::record_flt_last_trace_id(sql::ObSQLSessionInfo &session) {
     int ret = OB_SUCCESS;
     trace::UUID trc_uuid = OBTRACE->get_trace_id();
+    trace::UUID span_id;
     char last_trace_id[OB_MAX_UUID_STR_LENGTH + 1];
+    char last_span_id_buf[OB_MAX_UUID_STR_LENGTH + 1];
+    ObString last_span_id;
+    session.get_flt_span_id(last_span_id);
     int64_t pos = 0;
+    span_id.deserialize(last_span_id.ptr(), last_span_id.length(), pos);
+    pos = 0;
     trc_uuid.tostring(last_trace_id, OB_MAX_UUID_STR_LENGTH + 1, pos);
+    pos = 0;
+    span_id.tostring(last_span_id_buf, OB_MAX_UUID_STR_LENGTH + 1, pos);
     if (last_trace_id[0] == '\0') {
       // do nothing
     } else if (OB_FAIL(session.set_last_flt_trace_id(ObString(OB_MAX_UUID_STR_LENGTH + 1, last_trace_id)))) {
       LOG_WARN("failed  to set last flt trace id", K(ret), K(ObString(OB_MAX_UUID_STR_LENGTH + 1, last_trace_id)));
+    } else if (OB_FAIL(session.set_last_flt_span_id(ObString(OB_MAX_UUID_STR_LENGTH + 1, last_span_id_buf)))) {
+      LOG_WARN("failed  to set last flt span id", K(ret), K(ObString(OB_MAX_UUID_STR_LENGTH + 1, last_span_id_buf)));
     } else {
       // do nothing
     }
@@ -328,6 +338,9 @@ namespace sql
               LOG_WARN("failed to deserialize full link trace extra info", KP(buf), K(ret), K(pos), K(v_len));
             } else {
               // add to span
+              ObString empty_str;
+              empty_str.reset();
+              sess.set_last_flt_span_id(empty_str);
             }
             break;
           }

src/sql/monitor/flt/ob_flt_utils.h

@@ -38,12 +38,15 @@ namespace sql
       flt_trace_id_[0] = '\0';
       flt_span_id_[0] = '\0';
       last_flt_trace_id_buf_[0] = '\0';
+      last_flt_span_id_buf_[0] = '\0';
     }
     void reset() {
       flt_trace_id_[0] = '\0';
       flt_span_id_[0] = '\0';
       last_flt_trace_id_buf_[0] = '\0';
       last_flt_trace_id_.reset();
+      last_flt_span_id_buf_[0] = '\0';
+      last_flt_span_id_.reset();
       row_traceformat_ = true;
       trc_granuality_ = ObTraceGranularity::TRANS_LEVEL;
     }
@@ -52,6 +55,8 @@ namespace sql
     char flt_span_id_[common::OB_MAX_UUID_LENGTH + 1];
     ObString last_flt_trace_id_;
     char last_flt_trace_id_buf_[OB_MAX_UUID_STR_LENGTH + 1];
+    ObString last_flt_span_id_;
+    char last_flt_span_id_buf_[OB_MAX_UUID_STR_LENGTH + 1];
     bool row_traceformat_;
     ObTraceGranularity trc_granuality_;
   };

src/sql/session/ob_basic_session_info.cpp

@@ -2023,6 +2023,24 @@ void ObBasicSessionInfo::get_flt_span_id(ObString &span_id) const
   }
 }
 
+const ObString &ObBasicSessionInfo::get_last_flt_span_id() const
+{
+  return flt_vars_.last_flt_span_id_;
+}
+int ObBasicSessionInfo::set_last_flt_span_id(const common::ObString &span_id)
+{
+  int ret = OB_SUCCESS;
+  if (span_id.empty()) {
+    flt_vars_.last_flt_span_id_.reset();
+  } else {
+    int64_t span_len = std::min(static_cast<int64_t>(span_id.length()), OB_MAX_UUID_STR_LENGTH);
+    MEMCPY(flt_vars_.last_flt_span_id_buf_, span_id.ptr(), span_len);
+    flt_vars_.last_flt_span_id_buf_[span_len] = '\0';
+    flt_vars_.last_flt_span_id_.assign_ptr(flt_vars_.last_flt_span_id_buf_, span_len);
+  }
+  return ret;
+}
+
 const ObString &ObBasicSessionInfo::get_last_flt_trace_id() const
 {
   return flt_vars_.last_flt_trace_id_;
@@ -4026,7 +4044,8 @@ OB_DEF_SERIALIZE(ObBasicSessionInfo)
               thread_data_.user_client_addr_,
               process_query_time_,
               flt_vars_.last_flt_trace_id_,
-              flt_vars_.row_traceformat_);
+              flt_vars_.row_traceformat_,
+              flt_vars_.last_flt_span_id_);
   }();
   return ret;
 }
@@ -4183,6 +4202,7 @@ OB_DEF_DESERIALIZE(ObBasicSessionInfo)
   sys_var_in_pc_str_.reset(); //sys_var_in_pc_str_在反序列化系统变量阶段可能会被污染，需要reset掉
   config_in_pc_str_.reset();
   flt_vars_.last_flt_trace_id_.reset();
+  flt_vars_.last_flt_span_id_.reset();
   const ObTZInfoMap *tz_info_map = tz_info_wrap_.get_tz_info_offset().get_tz_info_map();
   LST_DO_CODE(OB_UNIS_DECODE,
               sys_vars_cache_.inc_data_,
@@ -4218,7 +4238,8 @@ OB_DEF_DESERIALIZE(ObBasicSessionInfo)
               thread_data_.user_client_addr_,
               process_query_time_,
               flt_vars_.last_flt_trace_id_,
-              flt_vars_.row_traceformat_);
+              flt_vars_.row_traceformat_,
+              flt_vars_.last_flt_span_id_);
   // deep copy string.
   if (OB_SUCC(ret)) {
     if (OB_FAIL(name_pool_.write_string(app_trace_id_, &app_trace_id_))) {
@@ -4244,7 +4265,7 @@ OB_DEF_DESERIALIZE(ObBasicSessionInfo)
   is_deserialized_ = true;
   tz_info_wrap_.set_tz_info_map(tz_info_map);
   set_last_flt_trace_id(flt_vars_.last_flt_trace_id_);
-
+  set_last_flt_span_id(flt_vars_.last_flt_span_id_);
   //在升级过程中,由于版本差异,高版本server如果收到低版本server发来的session变量,需要兼容处理
   //反序列化完成后, 由于后面存在再次序列化给其他server的场景, 所以需要补齐需要序列化的系统变量
   //fix以下场景   A(2.1)->B(2.2)->C(2.2)-> ret = -4016
@@ -4527,7 +4548,8 @@ OB_DEF_SERIALIZE_SIZE(ObBasicSessionInfo)
               thread_data_.user_client_addr_,
               process_query_time_,
               flt_vars_.last_flt_trace_id_,
-              flt_vars_.row_traceformat_);
+              flt_vars_.row_traceformat_,
+              flt_vars_.last_flt_span_id_);
   return len;
 }
 

src/sql/session/ob_basic_session_info.h

@@ -905,6 +905,8 @@ public:
   int set_flt_trace_id(ObString trace_id);
   const ObString &get_last_flt_trace_id() const;
   int set_last_flt_trace_id(const common::ObString &trace_id);
+  const ObString &get_last_flt_span_id() const;
+  int set_last_flt_span_id(const common::ObString &span_id);
   bool is_row_traceformat() const { return flt_vars_.row_traceformat_; }
   void set_is_row_traceformat(bool v) { flt_vars_.row_traceformat_ = v; }
   bool is_query_trc_granuality() const { return sys_vars_cache_.get_ob_enable_trace_log()?