java-app-best-practices: Add readOnlyPropagatesToServer

best-practices/java-app-best-practices.md

@@ -126,6 +126,10 @@ To verify that this setting already takes effect, you can do:
 - Go to TiDB monitoring dashboard and view the request command type through **Query Summary** > **CPS By Instance**.
 - If the number of `COM_STMT_EXECUTE` in the request is far more than the number of `COM_STMT_PREPARE`, it means this setting already takes effect.
 
+#### `readOnlyPropagatesToServer`
+
+You should disable the `readOnlyPropagatesToServer` property. This prevents the JDBC driver from sending the `SET SESSION TRANSACTION READ ONLY` statement to the server. TiDB does not support this statement, and it is also unnecessary because all TiDB nodes can handle read/write connections.
+
 #### Batch-related parameters
 
 While processing batch writes, it is recommended to configure `rewriteBatchedStatements=true`. After using `addBatch()` or `executeBatch()`, JDBC still sends SQL one by one by default, for example:
@@ -142,8 +146,6 @@ pstmt.executeBatch();
 
 Although `Batch` methods are used, the SQL statements sent to TiDB are still individual `INSERT` statements:
 
-{{< copyable "sql" >}}
-
 ```sql
 insert into t(a) values(10);
 insert into t(a) values(11);
@@ -152,16 +154,12 @@ insert into t(a) values(12);
 
 But if you set `rewriteBatchedStatements=true`, the SQL statements sent to TiDB will be a single `INSERT` statement:
 
-{{< copyable "sql" >}}
-
 ```sql
 insert into t(a) values(10),(11),(12);
 ```
 
 Note that the rewrite of the `INSERT` statements is to concatenate the values after multiple "values" keywords into a whole SQL statement. If the `INSERT` statements have other differences, they cannot be rewritten, for example:
 
-{{< copyable "sql" >}}
-
 ```sql
 insert into t (a) values (10) on duplicate key update a = 10;
 insert into t (a) values (11) on duplicate key update a = 11;
@@ -170,8 +168,6 @@ insert into t (a) values (12) on duplicate key update a = 12;
 
 The above `INSERT` statements cannot be rewritten into one statement. But if you change the three statements into the following ones:
 
-{{< copyable "sql" >}}
-
 ```sql
 insert into t (a) values (10) on duplicate key update a = values(a);
 insert into t (a) values (11) on duplicate key update a = values(a);
@@ -180,16 +176,12 @@ insert into t (a) values (12) on duplicate key update a = values(a);
 
 Then they meet the rewrite requirement. The above `INSERT` statements will be rewritten into the following one statement:
 
-{{< copyable "sql" >}}
-
 ```sql
 insert into t (a) values (10), (11), (12) on duplicate key update a = values(a);
 ```
 
 If there are three or more updates during the batch update, the SQL statements will be rewritten and sent as multiple queries. This effectively reduces the client-to-server request overhead, but the side effect is that a larger SQL statement is generated. For example:
 
-{{< copyable "sql" >}}
-
 ```sql
 update t set a = 10 where id = 1; update t set a = 11 where id = 2; update t set a = 12 where id = 3;
 ```
@@ -416,4 +408,4 @@ Based on commonly used Java components that interact with databases, this docume
 
 ## Need help?
 
-Ask the community on [Discord](https://discord.gg/DQZ2dy3cuc?utm_source=doc) or [Slack](https://slack.tidb.io/invite?team=tidb-community&channel=everyone&ref=pingcap-docs), or [submit a support ticket](/support.md).
+Ask the community on [Discord](https://discord.gg/DQZ2dy3cuc?utm_source=doc) or [Slack](https://slack.tidb.io/invite?team=tidb-community&channel=everyone&ref=pingcap-docs), or [submit a support ticket](/support.md).