Configuring Database and File System State Persistence¶
This section explains how to prevent the loss of data that can result from a system failure by persisting the state of WSO2 SI periodically either into a database system or into the file system.
Prerequisites¶
Before configuring RDBMS database persistence, the following prerequisites must be completed.
- One or more Siddhi Applications must be running in the WSO2 SI server.
- A working RDBMS instance that can be used for data persistence must exist.
-
The requirements of the datasource must be already defined.
-
Database persistence involves updating the databases connected to WSO2 Steaming Integrator with the latest information relating to the events that are being processed by WSO2 SI at a given time.
Configuring database system persistence¶
The supported databases are H2, MySQL, Postgres, MSSQL and Oracle. The
relevant jdbc driver jar should be downloaded and added to the
<SI_HOME>/lib
directory to prior to using database
system persistence.
To configure periodic data persistence, update the
<SI_HOME>/conf/server/deployment.yaml
file under
state.persistence
as follows:
Parameter | Purpose | Required Value |
---|---|---|
enabled |
This enables data persistence. | true |
intervalInMin |
The time interval in minutes that defines the interval in which state of Siddhi applications should be persisted | 1 |
revisionsToKeep |
The number of revisions to keep in the system. When a new persist takes place, the old revisions are removed. | 3 |
persistenceStore |
The persistence store . | org.wso2.carbon.stream.processor.core.persistence.DBPersistenceStore |
config > datasource |
The datasource to be used in persisting the state. The provided datasource should be properly defined in the deployment.yaml. For detailed instructions of how to configure a datasource, see Configuring Datasources . |
|
config > table |
The table that should be created and used for the persisting of the state. |
|
The following is a sample segment of the required configurations in the
<SI_HOME>/conf/server/deployment.yaml
file to
configure file system persistence.
Sample deployment.yaml segment
state.persistence:
enabled: true
intervalInMin: 1
revisionsToKeep: 3
persistenceStore: org.wso2.carbon.stream.processor.core.persistence.DBPersistenceStore
config:
datasource: <DATASOURCE NAME> # A datasource with this name should be defined in wso2.datasources namespace
table: <TABLE NAME>
Configuring file system persistence¶
This section explains how to persist the states of Siddhi applications
during a required time interval in the file system in order to maintain
back-ups. To configure state persistence, update the
<SI_HOME>/conf/server/deployment.yaml
file under
state
.p ersistence
as follows:
Parameter | Purpose | Required Value |
---|---|---|
enabled |
This enables data persistence. | true |
intervalInMin |
The time interval in minutes that defines the interval in which state of Siddhi applications should be persisted |
1 |
revisionsToKeep |
The number of revisions to keep in the system. When a new persist takes place, the old revisions are removed. | 3 |
persistenceStore |
The persistence store. |
|
config > location |
A fully qualified folder location to where the revision files should be persisted. |
|
The following is a sample segment of the required configurations in the
<SI_HOME>/conf/server/deployment.yaml
file to
configure file system persistence.
Sample deployment.yaml segment
state.persistence:
enabled: true
intervalInMin: 1
revisionsToKeep: 2
persistenceStore: org.wso2.carbon.stream.processor.core.persistence.FileSystemPersistenceStore
config:
location: siddhi-app-persistence
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