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Posted to commits@iotdb.apache.org by ja...@apache.org on 2022/11/08 11:27:36 UTC
[iotdb] branch master updated: [IOTDB-4871] Only call restore method for stateful trigger
This is an automated email from the ASF dual-hosted git repository.
jackietien pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/iotdb.git
The following commit(s) were added to refs/heads/master by this push:
new 14cd9c4666 [IOTDB-4871] Only call restore method for stateful trigger
14cd9c4666 is described below
commit 14cd9c46661b3a22015a71b763367a854118632f
Author: Liao Lanyu <14...@qq.com>
AuthorDate: Tue Nov 8 19:27:29 2022 +0800
[IOTDB-4871] Only call restore method for stateful trigger
---
docs/UserGuide/Process-Data/Triggers.md | 14 +++++++-------
docs/zh/UserGuide/Process-Data/Triggers.md | 14 +++++++-------
.../apache/iotdb/db/trigger/executor/TriggerExecutor.java | 3 ++-
3 files changed, 16 insertions(+), 15 deletions(-)
diff --git a/docs/UserGuide/Process-Data/Triggers.md b/docs/UserGuide/Process-Data/Triggers.md
index d9a4b4d04a..dd2bd201ad 100644
--- a/docs/UserGuide/Process-Data/Triggers.md
+++ b/docs/UserGuide/Process-Data/Triggers.md
@@ -139,12 +139,12 @@ Descriptions of the interfaces are as followed.
#### Lifecycle related interfaces
-| Interface | Description |
-| ------------------------------------------------------------ | ------------------------------------------------------------ |
-| *default void validate(TriggerAttributes attributes) throws Exception {}* | When you creates a trigger using the `CREATE TRIGGER` statement, you can specify the parameters that the trigger needs to use, and this interface will be used to verify the correctness of the parameters。 |
-| *default void onCreate(TriggerAttributes attributes) throws Exception {}* | This interface is called once when you create a trigger using the `CREATE TRIGGER` statement. During the lifetime of each trigger instance, this interface will be called only once. This interface is mainly used for the following functions: helping users to parse custom attributes in SQL statements (using `TriggerAttributes`). You can create or apply for resources, such as establishing external links, opening fi [...]
-| *default void onDrop() throws Exception {}* | This interface is called when you drop a trigger using the `DROP TRIGGER` statement. During the lifetime of each trigger instance, this interface will be called only once. This interface mainly has the following functions: it can perform the operation of resource release and can be used to persist the results of trigger calculations. |
-| *default void restore() throws Exception {}* | When the DataNode is restarted, the cluster will restore the trigger instance registered on the DataNode, and this interface will be called once during the process. After the DataNode where the stateful trigger instance is located goes down, the cluster will restore the trigger instance on another available DataNode, calling this interface once in the process. This interface can be used to customize recovery logic. |
+| Interface | Description [...]
+| ------------------------------------------------------------ |-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- [...]
+| *default void validate(TriggerAttributes attributes) throws Exception {}* | When you creates a trigger using the `CREATE TRIGGER` statement, you can specify the parameters that the trigger needs to use, and this interface will be used to verify the correctness of the parameters。 [...]
+| *default void onCreate(TriggerAttributes attributes) throws Exception {}* | This interface is called once when you create a trigger using the `CREATE TRIGGER` statement. During the lifetime of each trigger instance, this interface will be called only once. This interface is mainly used for the following functions: helping users to parse custom attributes in SQL statements (using `TriggerAttributes`). You can create or apply for resources, such as establishing external links, opening fi [...]
+| *default void onDrop() throws Exception {}* | This interface is called when you drop a trigger using the `DROP TRIGGER` statement. During the lifetime of each trigger instance, this interface will be called only once. This interface mainly has the following functions: it can perform the operation of resource release and can be used to persist the results of trigger calculations. [...]
+| *default void restore() throws Exception {}* | When the DataNode is restarted, the cluster will restore the trigger instance registered on the DataNode, and this interface will be called once for stateful trigger during the process. After the DataNode where the stateful trigger instance is located goes down, the cluster will restore the trigger instance on another available DataNode, calling this interface once in the process. This interface can be used to customize rec [...]
#### Data change listening related interfaces
@@ -455,7 +455,7 @@ During the process of creating and dropping triggers in the cluster, we maintain
## Notes
- The trigger takes effect from the time of registration, and does not process the existing historical data. **That is, only insertion requests that occur after the trigger is successfully registered will be listened to by the trigger. **
-- The fire process of trigger is synchronous currently, so you need to ensure the efficiency of the trigger, otherwise the writing performance may be greatly affected.
+- The fire process of trigger is synchronous currently, so you need to ensure the efficiency of the trigger, otherwise the writing performance may be greatly affected. **You need to guarantee concurrency safety of triggers yourself**.
- Please do no register too many triggers in the cluster. Because the trigger information is fully stored in the ConfigNode, and there is a copy of the information in all DataNodes
- **It is recommended to stop writing when registering triggers**. Registering a trigger is not an atomic operation. When registering a trigger, there will be an intermediate state in which some nodes in the cluster have registered the trigger, and some nodes have not yet registered successfully. To avoid write requests on some nodes being listened to by triggers and not being listened to on some nodes, we recommend not to perform writes when registering triggers.
- When the node holding the stateful trigger instance goes down, we will try to restore the corresponding instance on another node. During the recovery process, we will call the restore interface of the trigger class once.
diff --git a/docs/zh/UserGuide/Process-Data/Triggers.md b/docs/zh/UserGuide/Process-Data/Triggers.md
index 0afa019c88..ab310d7014 100644
--- a/docs/zh/UserGuide/Process-Data/Triggers.md
+++ b/docs/zh/UserGuide/Process-Data/Triggers.md
@@ -130,12 +130,12 @@ public interface Trigger {
#### 生命周期相关接口
-| 接口定义 | 描述 |
-|-------------------------------------------------------------------------| ------------------------------------------------------------ |
-| *default void validate(TriggerAttributes attributes) throws Exception {}* | 用户在使用 `CREATE TRIGGER` 语句创建触发器时，可以指定触发器需要使用的参数，该接口会用于验证参数正确性。 |
-| *default void onCreate(TriggerAttributes attributes) throws Exception {}* | 当您使用`CREATE TRIGGER`语句创建触发器后，该接口会被调用一次。在每一个触发器实例的生命周期内，该接口会且仅会被调用一次。该接口主要有如下作用：帮助用户解析 SQL 语句中的自定义属性（使用`TriggerAttributes`）。 可以创建或申请资源，如建立外部链接、打开文件等。 |
-| *default void onDrop() throws Exception {}* | 当您使用`DROP TRIGGER`语句删除触发器后，该接口会被调用。在每一个触发器实例的生命周期内，该接口会且仅会被调用一次。该接口主要有如下作用：可以进行资源释放的操作。可以用于持久化触发器计算的结果。 |
-| *default void restore() throws Exception {}* | 当重启 DataNode 时，集群会恢复 DataNode 上已经注册的触发器实例，在此过程中会调用一次该接口。有状态触发器实例所在的 DataNode 宕机后，集群会在另一个可用 DataNode 上恢复该触发器的实例，在此过程中会调用一次该接口。该接口可以用于自定义恢复逻辑。 |
+| 接口定义 | 描述 |
+|-------------------------------------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| *default void validate(TriggerAttributes attributes) throws Exception {}* | 用户在使用 `CREATE TRIGGER` 语句创建触发器时，可以指定触发器需要使用的参数，该接口会用于验证参数正确性。 |
+| *default void onCreate(TriggerAttributes attributes) throws Exception {}* | 当您使用`CREATE TRIGGER`语句创建触发器后，该接口会被调用一次。在每一个触发器实例的生命周期内，该接口会且仅会被调用一次。该接口主要有如下作用：帮助用户解析 SQL 语句中的自定义属性（使用`TriggerAttributes`）。 可以创建或申请资源，如建立外部链接、打开文件等。 |
+| *default void onDrop() throws Exception {}* | 当您使用`DROP TRIGGER`语句删除触发器后，该接口会被调用。在每一个触发器实例的生命周期内，该接口会且仅会被调用一次。该接口主要有如下作用：可以进行资源释放的操作。可以用于持久化触发器计算的结果。 |
+| *default void restore() throws Exception {}* | 当重启 DataNode 时，集群会恢复 DataNode 上已经注册的触发器实例，在此过程中会为该 DataNode 上的有状态触发器调用一次该接口。有状态触发器实例所在的 DataNode 宕机后，集群会在另一个可用 DataNode 上恢复该触发器的实例，在此过程中会调用一次该接口。该接口可以用于自定义恢复逻辑。 |
#### 数据变动侦听相关接口
@@ -441,7 +441,7 @@ SHOW TRIGGERS
## 重要注意事项
- 触发器从注册时开始生效，不对已有的历史数据进行处理。**即只有成功注册触发器之后发生的写入请求才会被触发器侦听到。**
-- 触发器目前采用**同步触发**，所以编写时需要保证触发器效率，否则可能会大幅影响写入性能。
+- 触发器目前采用**同步触发**，所以编写时需要保证触发器效率，否则可能会大幅影响写入性能。**您需要自己保证触发器内部的并发安全性**。
- 集群中**不能注册过多触发器**。因为触发器信息全量保存在 ConfigNode 中，并且在所有 DataNode 都有一份该信息的副本。
- **建议注册触发器时停止写入**。注册触发器并不是一个原子操作，注册触发器时，会出现集群内部分节点已经注册了该触发器，部分节点尚未注册成功的中间状态。为了避免部分节点上的写入请求被触发器侦听到，部分节点上没有被侦听到的情况，我们建议注册触发器时不要执行写入。
- 触发器将作为进程内程序执行，如果您的触发器编写不慎，内存占用过多，由于 IoTDB 并没有办法监控触发器所使用的内存，所以有 OOM 的风险。
diff --git a/server/src/main/java/org/apache/iotdb/db/trigger/executor/TriggerExecutor.java b/server/src/main/java/org/apache/iotdb/db/trigger/executor/TriggerExecutor.java
index 6b9e886899..308d71ae60 100644
--- a/server/src/main/java/org/apache/iotdb/db/trigger/executor/TriggerExecutor.java
+++ b/server/src/main/java/org/apache/iotdb/db/trigger/executor/TriggerExecutor.java
@@ -43,7 +43,8 @@ public class TriggerExecutor {
this.trigger = trigger;
// call Trigger#validate and Trigger#onCreate
onCreate();
- if (isRestoring) {
+ // Only call Trigger.restore() for stateful trigger
+ if (isRestoring && triggerInformation.isStateful()) {
onRestore();
}
}