query table CLUSTER_TIDB_TRX generate records in CLUSTER_TIDB_TRX

[vivid392845427]

Bug Report

Please answer these questions before submitting your issue. Thanks!

1. Minimal reproduce step (Required)

select * from CLUSTER_TIDB_TRX\G
select * from TIDB_TRX\G

2. What did you expect to see? (Required)

both of tables query return empty

3. What did you see instead (Required)

mysql> select * from CLUSTER_TIDB_TRX\G
*************************** 1. row ***************************
INSTANCE: tidb-cluster-tidb-0.tidb-cluster-tidb-peer.tidb-cluster.svc:10080
ID: 425339144411545601
START_TIME: 2021-06-01 09:34:31.150000
CURRENT_SQL_DIGEST: NULL
STATE: Normal
WAITING_START_TIME: NULL
LEN: 0
SIZE: 0
SESSION_ID: 51
USER: root
DB: information_schema
ALL_SQL_DIGESTS: [80fe946d359213f3d04e942a4ad48f8488512751a2b5168a14f7d3eec0242dce]
1 row in set (0.01 sec)

mysql> select DIGEST_TEXT from statements_summary where DIGEST='80fe946d359213f3d04e942a4ad48f8488512751a2b5168a14f7d3eec0242dce';
+----------------------------------+
| DIGEST_TEXT |
+----------------------------------+
| select * from cluster_tidb_trx |
+----------------------------------+
1 row in set (0.01 sec)

mysql> select * from TIDB_TRX\G
Empty set (0.00 sec)

4. What is your TiDB version? (Required)

Release Version: v5.1.0-alpha-84-gccaefa2a3
Edition: Community
Git Commit Hash: ccaefa2
Git Branch: master
UTC Build Time: 2021-06-01 06:50:46
GoVersion: go1.16.4
Race Enabled: false
TiKV Min Version: v3.0.0-60965b006877ca7234adaced7890d7b029ed1306
Check Table Before Drop: false

[vivid392845427]

anther scene：

tx1 on db1
mysql> create table t(a int);
Query OK, 0 rows affected (0.14 sec)

mysql> START TRANSACTION;
Query OK, 0 rows affected (0.00 sec)

mysql> select @@tidb_current_ts;
+--------------------+
| @@tidb_current_ts  |
+--------------------+
| 428396193555415041 |
+--------------------+
1 row in set (0.00 sec)

mysql> select instance, id, start_time, current_sql_digest,current_sql_digest_text, state, waiting_start_time, mem_buffer_keys, mem_buffer_bytes, session_id, user, db, all_sql_digests from information_schema.cluster_tidb_trx\G
*************************** 1. row ***************************
               instance: release-master-1012-1-tidb-0.release-master-1012-1-tidb-peer.user-zhaoyu.svc:10080
                     id: 428396193555415041
             start_time: 2021-10-14 08:56:28.160000
     current_sql_digest: NULL
current_sql_digest_text: NULL
                  state: Idle
     waiting_start_time: NULL
        mem_buffer_keys: 0
       mem_buffer_bytes: 0
             session_id: 17537
                   user: root
                     db: test
        all_sql_digests: ["9a4170a059f3113e196bdac9c156d6cecf3ccbef8eb238b878d04e61aa7d9741","58f3717da2d79c14773a1e3094aaddeff2b11747d3aef95741151af9acba9d44","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f"]
1 row in set (0.02 sec)

another connection not in transaction:
mysql> select instance, id, start_time, current_sql_digest,current_sql_digest_text, state, waiting_start_time, mem_buffer_keys, mem_buffer_bytes, session_id, user, db, all_sql_digests from information_schema.cluster_tidb_trx\G
*************************** 1. row ***************************
               instance: release-master-1012-1-tidb-0.release-master-1012-1-tidb-peer.user-zhaoyu.svc:10080
                     id: 428396193555415041
             start_time: 2021-10-14 08:56:28.160000
     current_sql_digest: NULL
current_sql_digest_text: NULL
                  state: Idle
     waiting_start_time: NULL
        mem_buffer_keys: 0
       mem_buffer_bytes: 0
             session_id: 17537
                   user: root
                     db: test
        all_sql_digests: ["9a4170a059f3113e196bdac9c156d6cecf3ccbef8eb238b878d04e61aa7d9741","58f3717da2d79c14773a1e3094aaddeff2b11747d3aef95741151af9acba9d44","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f","c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f"]
*************************** 2. row ***************************
               instance: release-master-1012-1-tidb-0.release-master-1012-1-tidb-peer.user-zhaoyu.svc:10080
                     id: 428396245381283841
             start_time: 2021-10-14 08:59:45.860000
     current_sql_digest: NULL
current_sql_digest_text: NULL
                  state: Idle
     waiting_start_time: NULL
        mem_buffer_keys: 0
       mem_buffer_bytes: 0
             session_id: 17543
                   user: root
                     db: test
        all_sql_digests: ["c8378315a107002c29f8d98875451b0463b7e5238fb9af45489026571a07ff8f"]
2 rows in set (0.01 sec)