*: modify some deprecated configuration items (#14219)

dashboard/dashboard-overview.md

@@ -59,7 +59,7 @@ By default, this area shows the latest 10 slow queries in the entire cluster ove
 
 ![Recent slow queries](/media/dashboard/dashboard-overview-slow-query.png)
 
-By default, the SQL query that is executed longer than 300 milliseconds is counted as a slow query and displayed on the table. You can change this threshold by modifying the [tidb_slow_log_threshold](/system-variables.md#tidb_slow_log_threshold) variable or the [slow-threshold](/tidb-configuration-file.md#slow-threshold) TiDB parameter.
+By default, the SQL query that is executed longer than 300 milliseconds is counted as a slow query and displayed on the table. You can change this threshold by modifying the [tidb_slow_log_threshold](/system-variables.md#tidb_slow_log_threshold) variable or the [instance.tidb_slow_log_threshold](/tidb-configuration-file.md#tidb_slow_log_threshold) TiDB parameter.
 
 The content displayed in this area is consistent with the more detailed [Slow Queries Page](/dashboard/dashboard-slow-query.md). You can click the **Recent Slow Queries** title to view the complete list. For details of the columns in this table, see this [Slow Queries Page](/dashboard/dashboard-slow-query.md).
 

dashboard/dashboard-slow-query.md

@@ -8,7 +8,7 @@ aliases: ['/docs/dev/dashboard/dashboard-slow-query/']
 
 On the Slow Queries page of TiDB Dashboard, you can search and view all slow queries in the cluster.
 
-By default, SQL queries with an execution time of more than 300 milliseconds are considered as slow queries. These queries are recorded in the [slow query logs](/identify-slow-queries.md) and can be searched via TiDB Dashboard. You can adjust the threshold of slow queries through the [`tidb_slow_log_threshold`](/system-variables.md#tidb_slow_log_threshold) session variable or the [`slow-threshold`](/tidb-configuration-file.md#slow-threshold) TiDB parameter.
+By default, SQL queries with an execution time of more than 300 milliseconds are considered as slow queries. These queries are recorded in the [slow query logs](/identify-slow-queries.md) and can be searched via TiDB Dashboard. You can adjust the threshold of slow queries through the [`tidb_slow_log_threshold`](/system-variables.md#tidb_slow_log_threshold) session variable or the [`instance.tidb_slow_log_threshold`](/tidb-configuration-file.md#tidb_slow_log_threshold) TiDB parameter.
 
 > **Note:**
 >

dynamic-config.md

@@ -335,9 +335,9 @@ The following TiDB configuration items can be modified dynamically:
 
 | Configuration item | SQL variable | Description |
 | :--- | :--- |
-| `log.enable-slow-log` | `tidb_enable_slow_log` | Whether to enable slow log |
-| `log.slow-threshold` | `tidb_slow_log_threshold` | The threshold of slow log |
-| `log.expensive-threshold` | `tidb_expensive_query_time_threshold` | The threshold of a expensive query |
+| `instance.tidb_enable_slow_log` | `tidb_enable_slow_log` | Whether to enable slow log |
+| `instance.tidb_slow_log_threshold` | `tidb_slow_log_threshold` | The threshold of slow log |
+| `instance.tidb_expensive_query_time_threshold` | `tidb_expensive_query_time_threshold` | The threshold of a expensive query |
 
 ### Modify TiFlash configuration dynamically
 

faq/deploy-and-maintain-faq.md

@@ -77,7 +77,7 @@ Check the time difference between the machine time of the monitor and the time w
 
 ### How to separately record the slow query log in TiDB? How to locate the slow query SQL statement?
 
-1. The slow query definition for TiDB is in the TiDB configuration file. The `slow-threshold: 300` parameter is used to configure the threshold value of the slow query (unit: millisecond).
+1. The slow query definition for TiDB is in the TiDB configuration file. The `tidb_slow_log_threshold: 300` parameter is used to configure the threshold value of the slow query (unit: millisecond).
 
 2. If a slow query occurs, you can locate the `tidb-server` instance where the slow query is and the slow query time point using Grafana and find the SQL statement information recorded in the log on the corresponding node.
 

quick-start-with-tidb.md

@@ -379,7 +379,7 @@ Other requirements for the target machine include:
 
     server_configs:
      tidb:
-       log.slow-threshold: 300
+       instance.tidb_slow_log_threshold: 300
      tikv:
        readpool.storage.use-unified-pool: false
        readpool.coprocessor.use-unified-pool: true

tidb-configuration-file.md

@@ -287,6 +287,10 @@ Configuration items related to log.
 
 ### `expensive-threshold`
 
+> **Warning:**
+>
+> Starting from v5.4.0, the `expensive-threshold` configuration item is deprecated and replaced by the system variable [`tidb_expensive_query_time_threshold`](/system-variables.md#tidb_expensive_query_time_threshold).
+
 - Outputs the threshold value of the number of rows for the `expensive` operation.
 - Default value: `10000`
 - When the number of query rows (including the intermediate results based on statistics) is larger than this value, it is an `expensive` operation and outputs log with the `[EXPENSIVE_QUERY]` prefix.
@@ -831,6 +835,16 @@ Configuration items related to read isolation.
 - Unit: Milliseconds
 - Before v6.1.0, this configuration is set by `slow-threshold`.
 
+### `tidb_expensive_query_time_threshold`
+
+- This configuration is used to set the threshold value that determines whether to print expensive query logs. The difference between expensive query logs and slow query logs is:
+    - Slow logs are printed after the statement is executed.
+    - Expensive query logs print the statements that are being executed, with execution time exceeding the threshold value, and their related information.
+- Default value: `60`
+- Range: `[10, 2147483647]`
+- Unit: Seconds
+- Before v5.4.0, this configuration is set by `expensive-threshold`.
+
 ### `tidb_record_plan_in_slow_log`
 
 - This configuration is used to control whether to include the execution plan of slow queries in the slow log.