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v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775) #23172

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185 changes: 185 additions & 0 deletions information-schema/information-schema-slow-query.md
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Original file line number Diff line number Diff line change
Expand Up @@ -35,6 +35,7 @@ DESC SLOW_QUERY;
The output is as follows:

```sql
<<<<<<< HEAD
+--------------------------------------------+-----------------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------------------------+-----------------+------+------+---------+-------+
Expand Down Expand Up @@ -130,11 +131,104 @@ The output is as follows:
| Query | longtext | YES | | NULL | |
+--------------------------------------------+-----------------+------+------+---------+-------+
90 rows in set (0.00 sec)
=======
+-------------------------------+---------------------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------------------------+---------------------+------+------+---------+-------+
| Time | timestamp(6) | NO | PRI | NULL | |
| Txn_start_ts | bigint(20) unsigned | YES | | NULL | |
| User | varchar(64) | YES | | NULL | |
| Host | varchar(64) | YES | | NULL | |
| Conn_ID | bigint(20) unsigned | YES | | NULL | |
| Session_alias | varchar(64) | YES | | NULL | |
| Exec_retry_count | bigint(20) unsigned | YES | | NULL | |
| Exec_retry_time | double | YES | | NULL | |
| Query_time | double | YES | | NULL | |
| Parse_time | double | YES | | NULL | |
| Compile_time | double | YES | | NULL | |
| Rewrite_time | double | YES | | NULL | |
| Preproc_subqueries | bigint(20) unsigned | YES | | NULL | |
| Preproc_subqueries_time | double | YES | | NULL | |
| Optimize_time | double | YES | | NULL | |
| Wait_TS | double | YES | | NULL | |
| Prewrite_time | double | YES | | NULL | |
| Wait_prewrite_binlog_time | double | YES | | NULL | |
| Commit_time | double | YES | | NULL | |
| Get_commit_ts_time | double | YES | | NULL | |
| Commit_backoff_time | double | YES | | NULL | |
| Backoff_types | varchar(64) | YES | | NULL | |
| Resolve_lock_time | double | YES | | NULL | |
| Local_latch_wait_time | double | YES | | NULL | |
| Write_keys | bigint(22) | YES | | NULL | |
| Write_size | bigint(22) | YES | | NULL | |
| Prewrite_region | bigint(22) | YES | | NULL | |
| Txn_retry | bigint(22) | YES | | NULL | |
| Cop_time | double | YES | | NULL | |
| Process_time | double | YES | | NULL | |
| Wait_time | double | YES | | NULL | |
| Backoff_time | double | YES | | NULL | |
| LockKeys_time | double | YES | | NULL | |
| Request_count | bigint(20) unsigned | YES | | NULL | |
| Total_keys | bigint(20) unsigned | YES | | NULL | |
| Process_keys | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_delete_skipped_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_key_skipped_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_cache_hit_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_read_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_read_byte | bigint(20) unsigned | YES | | NULL | |
| DB | varchar(64) | YES | | NULL | |
| Index_names | varchar(100) | YES | | NULL | |
| Is_internal | tinyint(1) | YES | | NULL | |
| Digest | varchar(64) | YES | | NULL | |
| Stats | varchar(512) | YES | | NULL | |
| Cop_proc_avg | double | YES | | NULL | |
| Cop_proc_p90 | double | YES | | NULL | |
| Cop_proc_max | double | YES | | NULL | |
| Cop_proc_addr | varchar(64) | YES | | NULL | |
| Cop_wait_avg | double | YES | | NULL | |
| Cop_wait_p90 | double | YES | | NULL | |
| Cop_wait_max | double | YES | | NULL | |
| Cop_wait_addr | varchar(64) | YES | | NULL | |
| Mem_max | bigint(20) | YES | | NULL | |
| Disk_max | bigint(20) | YES | | NULL | |
| KV_total | double | YES | | NULL | |
| PD_total | double | YES | | NULL | |
| Backoff_total | double | YES | | NULL | |
| Write_sql_response_total | double | YES | | NULL | |
| Result_rows | bigint(22) | YES | | NULL | |
| Warnings | longtext | YES | | NULL | |
| Backoff_Detail | varchar(4096) | YES | | NULL | |
| Prepared | tinyint(1) | YES | | NULL | |
| Succ | tinyint(1) | YES | | NULL | |
| IsExplicitTxn | tinyint(1) | YES | | NULL | |
| IsWriteCacheTable | tinyint(1) | YES | | NULL | |
| Plan_from_cache | tinyint(1) | YES | | NULL | |
| Plan_from_binding | tinyint(1) | YES | | NULL | |
| Has_more_results | tinyint(1) | YES | | NULL | |
| Resource_group | varchar(64) | YES | | NULL | |
| Request_unit_read | double | YES | | NULL | |
| Request_unit_write | double | YES | | NULL | |
| Time_queued_by_rc | double | YES | | NULL | |
| Tidb_cpu_time | double | YES | | NULL | |
| Tikv_cpu_time | double | YES | | NULL | |
| Plan | longtext | YES | | NULL | |
| Plan_digest | varchar(128) | YES | | NULL | |
| Binary_plan | longtext | YES | | NULL | |
| Prev_stmt | longtext | YES | | NULL | |
| Session_connect_attrs | json | YES | | NULL | |
| Query | longtext | YES | | NULL | |
+-------------------------------+---------------------+------+------+---------+-------+
82 rows in set (0.00 sec)
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
```

The maximum statement length of the `Query` column is limited by the [`tidb_stmt_summary_max_sql_length`](/system-variables.md#tidb_stmt_summary_max_sql_length-new-in-v40) system variable.

<<<<<<< HEAD
The `Session_connect_attrs` column stores session connection attributes in JSON format parsed from the slow log. TiDB controls the maximum payload size written to this field using [`performance_schema_session_connect_attrs_size`](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v900).
=======
The `Session_connect_attrs` column stores session connection attributes in JSON format parsed from the slow log. TiDB controls the maximum payload size written to this field using [`performance_schema_session_connect_attrs_size`](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v857).
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
Comment on lines +227 to +231

@gemini-code-assist gemini-code-assist Bot Jun 30, 2026

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medium

There is an unresolved merge conflict here. Please resolve it by keeping the v8.5.7 version and removing the v9.0.0 version and conflict markers:

The Session_connect_attrs column stores session connection attributes in JSON format parsed from the slow log. TiDB controls the maximum payload size written to this field using performance_schema_session_connect_attrs_size.


## CLUSTER_SLOW_QUERY table

Expand All @@ -157,6 +251,7 @@ DESC CLUSTER_SLOW_QUERY;
The output is as follows:

```sql
<<<<<<< HEAD
+--------------------------------------------+-----------------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------------------------------------------+-----------------+------+------+---------+-------+
Expand Down Expand Up @@ -253,6 +348,96 @@ The output is as follows:
| Query | longtext | YES | | NULL | |
+--------------------------------------------+-----------------+------+------+---------+-------+
91 rows in set (0.00 sec)
=======
+-------------------------------+---------------------+------+------+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------------------------------+---------------------+------+------+---------+-------+
| INSTANCE | varchar(64) | YES | | NULL | |
| Time | timestamp(6) | NO | PRI | NULL | |
| Txn_start_ts | bigint(20) unsigned | YES | | NULL | |
| User | varchar(64) | YES | | NULL | |
| Host | varchar(64) | YES | | NULL | |
| Conn_ID | bigint(20) unsigned | YES | | NULL | |
| Session_alias | varchar(64) | YES | | NULL | |
| Exec_retry_count | bigint(20) unsigned | YES | | NULL | |
| Exec_retry_time | double | YES | | NULL | |
| Query_time | double | YES | | NULL | |
| Parse_time | double | YES | | NULL | |
| Compile_time | double | YES | | NULL | |
| Rewrite_time | double | YES | | NULL | |
| Preproc_subqueries | bigint(20) unsigned | YES | | NULL | |
| Preproc_subqueries_time | double | YES | | NULL | |
| Optimize_time | double | YES | | NULL | |
| Wait_TS | double | YES | | NULL | |
| Prewrite_time | double | YES | | NULL | |
| Wait_prewrite_binlog_time | double | YES | | NULL | |
| Commit_time | double | YES | | NULL | |
| Get_commit_ts_time | double | YES | | NULL | |
| Commit_backoff_time | double | YES | | NULL | |
| Backoff_types | varchar(64) | YES | | NULL | |
| Resolve_lock_time | double | YES | | NULL | |
| Local_latch_wait_time | double | YES | | NULL | |
| Write_keys | bigint(22) | YES | | NULL | |
| Write_size | bigint(22) | YES | | NULL | |
| Prewrite_region | bigint(22) | YES | | NULL | |
| Txn_retry | bigint(22) | YES | | NULL | |
| Cop_time | double | YES | | NULL | |
| Process_time | double | YES | | NULL | |
| Wait_time | double | YES | | NULL | |
| Backoff_time | double | YES | | NULL | |
| LockKeys_time | double | YES | | NULL | |
| Request_count | bigint(20) unsigned | YES | | NULL | |
| Total_keys | bigint(20) unsigned | YES | | NULL | |
| Process_keys | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_delete_skipped_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_key_skipped_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_cache_hit_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_read_count | bigint(20) unsigned | YES | | NULL | |
| Rocksdb_block_read_byte | bigint(20) unsigned | YES | | NULL | |
| DB | varchar(64) | YES | | NULL | |
| Index_names | varchar(100) | YES | | NULL | |
| Is_internal | tinyint(1) | YES | | NULL | |
| Digest | varchar(64) | YES | | NULL | |
| Stats | varchar(512) | YES | | NULL | |
| Cop_proc_avg | double | YES | | NULL | |
| Cop_proc_p90 | double | YES | | NULL | |
| Cop_proc_max | double | YES | | NULL | |
| Cop_proc_addr | varchar(64) | YES | | NULL | |
| Cop_wait_avg | double | YES | | NULL | |
| Cop_wait_p90 | double | YES | | NULL | |
| Cop_wait_max | double | YES | | NULL | |
| Cop_wait_addr | varchar(64) | YES | | NULL | |
| Mem_max | bigint(20) | YES | | NULL | |
| Disk_max | bigint(20) | YES | | NULL | |
| KV_total | double | YES | | NULL | |
| PD_total | double | YES | | NULL | |
| Backoff_total | double | YES | | NULL | |
| Write_sql_response_total | double | YES | | NULL | |
| Result_rows | bigint(22) | YES | | NULL | |
| Warnings | longtext | YES | | NULL | |
| Backoff_Detail | varchar(4096) | YES | | NULL | |
| Prepared | tinyint(1) | YES | | NULL | |
| Succ | tinyint(1) | YES | | NULL | |
| IsExplicitTxn | tinyint(1) | YES | | NULL | |
| IsWriteCacheTable | tinyint(1) | YES | | NULL | |
| Plan_from_cache | tinyint(1) | YES | | NULL | |
| Plan_from_binding | tinyint(1) | YES | | NULL | |
| Has_more_results | tinyint(1) | YES | | NULL | |
| Resource_group | varchar(64) | YES | | NULL | |
| Request_unit_read | double | YES | | NULL | |
| Request_unit_write | double | YES | | NULL | |
| Time_queued_by_rc | double | YES | | NULL | |
| Tidb_cpu_time | double | YES | | NULL | |
| Tikv_cpu_time | double | YES | | NULL | |
| Plan | longtext | YES | | NULL | |
| Plan_digest | varchar(128) | YES | | NULL | |
| Binary_plan | longtext | YES | | NULL | |
| Prev_stmt | longtext | YES | | NULL | |
| Session_connect_attrs | json | YES | | NULL | |
| Query | longtext | YES | | NULL | |
+-------------------------------+---------------------+------+------+---------+-------+
83 rows in set (0.00 sec)
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
```

When the cluster system table is queried, TiDB does not obtain data from all nodes, but pushes down the related calculation to other nodes. The execution plan is as follows:
Expand Down
4 changes: 4 additions & 0 deletions performance-schema/performance-schema-session-connect-attrs.md
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Expand Up @@ -69,7 +69,11 @@ Fields in the `SESSION_CONNECT_ATTRS` table are described as follows:

## Size limit and truncation

<<<<<<< HEAD
TiDB uses the [`performance_schema_session_connect_attrs_size`](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v900) global system variable to control the maximum total size of connection attributes per session.
=======
TiDB uses the [`performance_schema_session_connect_attrs_size`](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v857) global system variable to control the maximum total size of connection attributes per session.
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
Comment on lines +72 to +76

@gemini-code-assist gemini-code-assist Bot Jun 30, 2026

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medium

There is an unresolved merge conflict here. Please resolve it by keeping the v8.5.7 version and removing the v9.0.0 version and conflict markers:

TiDB uses the performance_schema_session_connect_attrs_size global system variable to control the maximum total size of connection attributes per session.


- Default value: `4096` bytes
- Range: `[-1, 65536]`
Expand Down
4 changes: 4 additions & 0 deletions system-variable-reference.md
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Expand Up @@ -605,7 +605,11 @@ Referenced in:
Referenced in:

- [`SESSION_CONNECT_ATTRS`](/performance-schema/performance-schema-session-connect-attrs.md)
<<<<<<< HEAD
- [System Variables](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v900)
=======
- [System Variables](/system-variables.md#performance_schema_session_connect_attrs_size-new-in-v857)
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
Comment on lines +608 to +612

@gemini-code-assist gemini-code-assist Bot Jun 30, 2026

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medium

There is an unresolved merge conflict here. Please resolve it by keeping the v8.5.7 version and removing the v9.0.0 version and conflict markers:


### plugin_dir

Expand Down
4 changes: 4 additions & 0 deletions system-variables.md
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Expand Up @@ -811,7 +811,11 @@ mysql> SHOW GLOBAL VARIABLES LIKE 'max_prepared_stmt_count';
* In a cluster with a large number of Regions, the PD leader experiences high CPU pressure due to the increased overhead of handling heartbeats and scheduling tasks.
* In a TiDB cluster with many TiDB instances, the PD leader experiences high CPU pressure due to a high concurrency of requests for Region information.

<<<<<<< HEAD
### performance_schema_session_connect_attrs_size <span class="version-mark">New in v9.0.0</span>
=======
### performance_schema_session_connect_attrs_size <span class="version-mark">New in v8.5.7</span>
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
Comment on lines +814 to +818

@gemini-code-assist gemini-code-assist Bot Jun 30, 2026

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medium

There is an unresolved merge conflict here. Please resolve it by keeping the v8.5.7 version and removing the v9.0.0 version and conflict markers.

Suggested change
<<<<<<< HEAD
### performance_schema_session_connect_attrs_size <span class="version-mark">New in v9.0.0</span>
=======
### performance_schema_session_connect_attrs_size <span class="version-mark">New in v8.5.7</span>
>>>>>>> 68bb5e64f0 (v8.5.7: support logging session connect attrs to slow query log (#22547) (#22775))
### performance_schema_session_connect_attrs_size <span class="version-mark">New in v8.5.7</span>


- Scope: GLOBAL
- Persists to cluster: Yes
Expand Down