Support PostgreSQL JSONB data type in JdbcEventStorageEngine

JdbcEventStorageEngine doesn’t easily support using nonstandard data types such as PostgreSQL’s JSONB for the payload and metadata columns.

The problem is that the queries pass the output of the serializer to the JDBC driver with PreparedStatement.setObject(), but there’s no way to communicate type information.

In the case of PostgreSQL’s JDBC driver, you can insert into a JSONB column in either of two ways. First, you can add an explicit cast to the prepared statement, e.g.,

PreparedStatement ps = conn.prepareStatement("INSERT INTO foo (bar) VALUES (?::JSONB)");
ps.setObject(1, jsonFromSerializer);

Or you can pass the value as a PGobject with type information.

PreparedStatement ps = connection.prepareStatement("INSERT INTO foo (bar) VALUES (?)");
PGobject pgObject = new PGobject();
pgObject.setType("JSONB");
pgObject.setValue(jsonFromSerializer);
ps.setObject(1, pgObject);

Either approach could be exposed as a public API by JdbcEventStorageEngine. Maybe something along the lines of one of

storageEngineBuilder
    .payloadBindString("?::JSONB")
    .metaDataBindString("?::JSONB")

or

private PGobject wrapInPgObject(Object data) {
    PGobject pgObject = new PGobject();
    pgObject.setType("JSONB");
    pgObject.setValue(data);
    return pgObject;
}

...
storageEngineBuilder
    .payloadConverter(this::wrapInPgObject)
    .metaDataConverter(this::wrapInPgObject);

[smcvb]

Sure thing @Raido0812! This blog by my former colleague Patrick was a consequence of getting PostgreSQL’s JSONB stuff to work.

[sgrimm-sg]

That suggestion seems like it might do the trick, yes. Obviously we’ll need to try it to make sure, but it sounds reasonable.