Historical Alarm Storage

Purpose

This target writes alarm activation and recovery records at or above a selected level to a database. Use the stored records for historical alarm queries and reports.

Configure forwarding group ranges, offline cache, and runtime state through Data Forwarding. This page covers only the alarm table, level filter, dual-database mirror, and debug panels specific to historical alarms.

Open the plugin

Open Development Configuration → Data Forwarding and:

1. Save the forwarding-group variable range.
2. Add a target, choose Historical Alarm Storage, and fill in the basic target information.
3. Open Target properties and configure the relational database, table, retention, time zone, and minimum alarm level.
4. Optionally select a saved Historical alarm table script or enable the relational dual-database mirror. These modes are mutually exclusive.
5. Save and enable the target, then activate and recover an approved test alarm.

Basic target information

Setting	Default	Configuration
Group	-	Select a saved forwarding group.
Target name	-	Required and unique within the group.
Enable	Enabled	Disable to stop alarm-table initialization and writes.
Log level	Info	Temporarily use Debug for database or alarm-write diagnostics.
Start timeout	60 seconds	Valid range is 1 to 3600 seconds.

Target properties

Setting	Default	Configuration
Database type	SqlServer	Supports SqlServer, MySql, Sqlite, and PostgreSql.
Split-table strategy	No split	Relational databases can split by day, week, month, quarter, year, or a custom split service.
Connection string	Development SQL Server example	Replace with the actual endpoint, database, account, and password; the account needs create, query, insert, and delete permissions.
Historical alarm table	historyAlarm	Table storing alarm activation and recovery records. Use a separate name for each target when appropriate.
Retention days	3650	Positive integer; values below 1 are normalized to 1. Cleanup uses alarm EventTime.
Historical alarm table script	Empty	Select a saved Dynamic SQL expression. The script owns table creation, writes, and cleanup; empty uses the standard table.
Time-zone offset	+08:00	Enter a fixed offset such as +08:00 or -05:00; empty means UTC. Use the same convention when querying.
Minimum alarm level	0	Stores only alarms where AlarmLevel >= this value; lower-level alarms and recoveries are ignored.
Dual-database mirror	Disabled	Relational standard tables only; fill a different physical backup database.

Relational connection strings

Database	Example
SQL Server	Server=127.0.0.1,1433;Database=thingsgateway_alarm;User Id=history_user;Password=<password>;TrustServerCertificate=True;
MySQL	Server=127.0.0.1;Port=3306;Database=thingsgateway_alarm;Uid=history_user;Pwd=<password>;
SQLite	Data Source=DB/alarm.db;journal mode=WAL
PostgreSQL	Host=127.0.0.1;Port=5432;Database=thingsgateway_alarm;Username=history_user;Password=<password>;

Dual-database mirroring supports SQL Server, MySQL, SQLite, and PostgreSQL. The primary and backup must be different physical databases, and Historical alarm table script must be empty. The automatic check, automatic fill, and capacity fields are the same as Historical Data Storage.

Target-variable properties

This plugin has no target-variable properties. Alarm inclusion is controlled only by the forwarding-group range and Minimum alarm level.

Cache and capacity

Setting	Default	Configuration
Enable failed-write retry cache	Disabled	Enable to retain alarms when the database is unavailable and replay them after recovery.
Cache file maximum rows	262144	Maximum CacheDB outbox alarm rows.
Upload chunk size	2000	Maximum alarms per write or replay batch.
Memory queue limit	100000	Maximum in-memory alarm records.
Filter offline data	Disabled	The property is exposed by the common target, but alarm acceptance is controlled by group range and minimum alarm level.
Upload concurrency	1	Default serial write; increase only after database load testing.

Target debug

Open Development Configuration → Data Forwarding, select the forwarding group and target, and open Debug.

Feature	Purpose
Forwarding pipeline	Shows the forwarding group range and alarm data entering the target.
Cache outbox	Shows pending alarms, retained retries, and the latest error.

Forwarding pipeline

Use the pipeline to confirm the forwarding group range, target state, and alarm data entering the target.

Cache outbox

The cache outbox shows the alarm queue, CacheDB pending rows, retained retries, and latest error. When offline cache is enabled, pending alarms are written after the database recovers.

Verify the target

1. Enable the forwarding group and target, then confirm that the target is online.
2. Use an approved test variable to activate and recover an alarm at or above Minimum alarm level.
3. Query the historical alarm table and confirm that both activation and recovery records were written.

Troubleshooting

Symptom	Check
Alarm is not stored	The alarm was activated, its level meets the minimum, and the target is online.
Target does not start	Database connection, table name, split-table strategy, and account permissions.
Alarms are not written after recovery	Offline cache setting, cache outbox, and target log.
Dual-database mirror cannot start	The primary and backup are different, both database types are supported, and the historical alarm table script is empty.

Related links

• Data Forwarding: Forwarding groups, ranges, triggers, cache, redundancy, and target runtime operations.
• Alarm Configuration: Configure alarm conditions and levels.
• Plugin Manual Index: Other collection and data-forwarding plugins.