corda/docs/source/node-database.rst

Node database

Default in-memory database

By default, nodes store their data in an H2 database. The database (a file persistence.mv.db) is created at the first node startup with the administrator user 'sa' and a blank password. The user name and password can be changed in node configuration:

dataSourceProperties = {
    dataSource.user = [USER]
    dataSource.password = [PASSWORD]
}

Note, changing user/password for the existing node in node.conf will not update them in the H2 database, you need to login to the database first to create new user or change the user password. The database password is required only when the H2 database is exposed on non-localhost address (which is disabled by default). The node requires the user with administrator permissions in order to creates tables upon the first startup or after deplying new CorDapps with own tables.

You can connect directly to a running node's database to see its stored states, transactions and attachments as follows:

• Enable the H2 database access in the node configuration using the following syntax:

  h2Settings {
      address: "localhost:0"
  }

• Download the last stable h2 platform-independent zip, unzip the zip, and navigate in a terminal window to the unzipped folder

• Change directories to the bin folder: cd h2/bin

• Run the following command to open the h2 web console in a web browser tab:

  • Unix: sh h2.sh
  • Windows: h2.bat

• Find the node's JDBC connection string. Each node outputs its connection string in the terminal window as it starts up. In a terminal window where a node is running, look for the following string:

  Database connection URL is : jdbc:h2:tcp://10.18.0.150:56736/node

• Paste this string into the JDBC URL field and click Connect, using the default username (sa) and no password.

You will be presented with a web interface that shows the contents of your node's storage and vault, and provides an interface for you to query them using SQL.

The default behaviour is to expose the H2 database on localhost. This can be overridden in the node configuration using h2Settings.address and specifying the address of the network interface to listen on, or simply using 0.0.0.0:0 to listen on all interfaces. The node requires a database password to be set when the database is exposed on the network interface to listen on.

PostgreSQL

Nodes can also be configured to use PostgreSQL 9.6, using PostgreSQL JDBC Driver 42.1.4.

Warning

This is an experimental community contribution. The Corda continuous integration pipeline does not run unit tests or integration tests of this feature.

Configuration

Here is an example node configuration for PostgreSQL:

dataSourceProperties = {
    dataSourceClassName = "org.postgresql.ds.PGSimpleDataSource"
    dataSource.url = "jdbc:postgresql://[HOST]:[PORT]/postgres"
    dataSource.user = [USER]
    dataSource.password = [PASSWORD]
}
database = {
    transactionIsolationLevel = READ_COMMITTED
    schema = [SCHEMA]
}

Note that:

• The database.schema property is optional
• The value of database.schema is not wrapped in double quotes and Postgres always treats it as a lower-case value (e.g. AliceCorp becomes alicecorp)
• If you provide a custom database.schema, its value must either match the dataSource.user value to end up on the standard schema search path according to the PostgreSQL documentation, or the schema search path must be set explicitly for the user.

SQLServer

Nodes also have untested support for Microsoft SQL Server 2017, using Microsoft JDBC Driver 6.2 for SQL Server.

Warning

This is an experimental community contribution, and is currently untested. We welcome pull requests to add tests and additional support for this feature.

Configuration

Here is an example node configuration for SQLServer:

dataSourceProperties = {
    dataSourceClassName = "com.microsoft.sqlserver.jdbc.SQLServerDataSource"
    dataSource.url = "jdbc:sqlserver://[HOST]:[PORT];databaseName=[DATABASE_NAME]"
    dataSource.user = [USER]
    dataSource.password = [PASSWORD]
}
database = {
    transactionIsolationLevel = READ_COMMITTED
    schema = [SCHEMA]
}
jarDirs = ["[FULL_PATH]/sqljdbc_6.2/enu/"]

Note that:

• The database.schema property is optional and is ignored as of release 3.1.

* Ensure the directory referenced by jarDirs contains only one JDBC driver JAR file; by the default,

sqljdbc_6.2/enu/contains two JDBC JAR file for different Java versions.

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