njnu-seafish commented on code in PR #18549:
URL:
https://github.com/apache/dolphinscheduler/pull/18549#discussion_r3904075058
##########
dolphinscheduler-dao/src/main/resources/org/apache/dolphinscheduler/dao/mapper/AlertMapper.xml:
##########
@@ -51,6 +51,42 @@
having count(*) = 0
</insert>
+ <!-- MySQL -->
+ <insert id="insertTaskResultAlertIfAbsent" databaseId="mysql">
+ INSERT INTO t_ds_alert(sign, title, content, alert_status,
warning_type, log, alertgroup_id,
+ create_time, update_time, project_code,
workflow_definition_code,
+ workflow_instance_id, alert_type)
+ VALUES (#{alert.sign}, #{alert.title}, #{alert.content},
#{alert.alertStatus.code},
+ #{alert.warningType.code}, #{alert.log},
#{alert.alertGroupId}, #{alert.createTime},
+ #{alert.updateTime}, #{alert.projectCode},
#{alert.workflowDefinitionCode},
+ #{alert.workflowInstanceId}, #{alert.alertType.code})
+ ON DUPLICATE KEY UPDATE id = id
+ </insert>
+
+ <!-- H2 -->
+ <insert id="insertTaskResultAlertIfAbsent" databaseId="h2">
+ MERGE INTO t_ds_alert(sign, title, content, alert_status,
warning_type, log, alertgroup_id,
+ create_time, update_time, project_code, workflow_definition_code,
+ workflow_instance_id, alert_type)
+ KEY(sign, workflow_instance_id, alert_type)
+ VALUES (#{alert.sign}, #{alert.title}, #{alert.content},
#{alert.alertStatus.code},
+ #{alert.warningType.code}, #{alert.log}, #{alert.alertGroupId},
#{alert.createTime},
+ #{alert.updateTime}, #{alert.projectCode},
#{alert.workflowDefinitionCode},
+ #{alert.workflowInstanceId}, #{alert.alertType.code})
+ </insert>
+
+ <!-- PostgreSQL -->
+ <insert id="insertTaskResultAlertIfAbsent" databaseId="postgresql">
+ INSERT INTO t_ds_alert(sign, title, content, alert_status,
warning_type, log, alertgroup_id,
+ create_time, update_time, project_code,
workflow_definition_code,
+ workflow_instance_id, alert_type)
+ VALUES (#{alert.sign}, #{alert.title}, #{alert.content},
#{alert.alertStatus.code},
+ #{alert.warningType.code}, #{alert.log},
#{alert.alertGroupId}, #{alert.createTime},
+ #{alert.updateTime}, #{alert.projectCode},
#{alert.workflowDefinitionCode},
+ #{alert.workflowInstanceId}, #{alert.alertType.code})
+ ON CONFLICT (sign, workflow_instance_id, alert_type) DO NOTHING
+ </insert>
Review Comment:
> Don't use this writing method, which will lead to poor database
performance.
Replaced the dialect-specific upsert (ON DUPLICATE KEY UPDATE / MERGE INTO /
ON CONFLICT DO NOTHING) with a single dialect-neutral INSERT ... SELECT ...
WHERE NOT EXISTS statement.
The uk_alert_dedup unique constraint is retained as a concurrent-safety net.
If a race condition causes two threads to pass NOT EXISTS simultaneously, the
constraint catches the duplicate insert.
The DAO layer catches DuplicateKeyException and returns 0, ensuring
idempotency without propagating exceptions to the caller.
> String sign = generateSign(alert);
alert.setSign(sign);
try {
int count = alertMapper.insertTaskResultAlertIfAbsent(alert);
if (count > 0) {
log.info("add task result alert to db , alert: {}", alert);
} else {
log.info("skip duplicate task result alert, sign: {},
workflowInstanceId: {}", sign,
alert.getWorkflowInstanceId());
}
return count;
} catch (DuplicateKeyException e) {
// Concurrent race: NOT EXISTS passed but another thread
inserted first.
// The uk_alert_dedup unique constraint caught it — treat as a
skip.
log.info("skip duplicate task result alert (concurrent race),
sign: {}, workflowInstanceId: {}", sign,
alert.getWorkflowInstanceId());
return 0;
}
fully implements a dual-safeguard idempotent write mechanism combining
application-layer deduplication with a database unique constraint as a fallback.
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