The openGauss connector allows querying and creating tables in an external openGauss database. This can be used to join data between different systems like openGauss and Hive, or between two different openGauss instances.
To configure the openGauss connector, create a catalog properties file in
etc/catalog named, for example,
opengauss.properties, to mount the openGauss connector as the
opengauss catalog. Create the file with the following contents, replacing the connection properties as appropriate for your setup:
connector.name=openguass connection-url=jdbc:postgresql://example.net:5432/database connection-user=root connection-password=secret
Multiple openGauss Databases or Servers
The openGauss connector can only access a single database within a openGauss server. Thus, if you have multiple openGauss databases, or want to connect to multiple openGauss servers, you must configure multiple instances of the openGauss connector.
To add another catalog, simply add another properties file to
etc/catalog with a different name (making sure it ends in
.properties). For example, if you name the property file
sales.properties, openLooKeng will create a catalog named
sales using the configured connector.
The openGauss connector provides a schema for every openGauss schema. You can see the available openGauss schemas by running
SHOW SCHEMAS FROM opengauss;
If you have a openGauss schema named
public, you can view the tables in this schema by running
SHOW TABLES FROM opengauss.public;
You can see a list of the columns in the
hetutb table in the
public database using either of the following:
DESCRIBE opengauss.public.hetutb; SHOW COLUMNS FROM opengauss.public.hetutb;
Finally, you can access the
hetutb table in the
SELECT * FROM opengauss.public.hetutb;
If you used a different name for your catalog properties file, use that catalog name instead of
opengauss in the above examples.
- When the compatibility type of the openGuass database is O (DBCOMPATIBILITY = A), the
Datedata type is not supported.
- The openGuass driver does not support put the connection in read-only mode to enable database optimization at present.
- The unit of openGauss’s
Characterdata type is byte (e.g.
nindicates to the byte length of
VARCHAR(n)data type), the unit of openLooKeng’s
Characterdata type is character (e.g.
nindicates to the character length of
VARCHAR(n)data type). openGauss connector does not support use
create-table-asmethod to create a table containing
Characterdata type directly, the byte length of
Characterdata type needs to manually specified.
use-connection-poolconfiguration is not supported.
opengauss.metadata.speedup=truein catalog properties file can speed up DatabaseMetaData access, its default value is false.
If the subsequent version of openGuass supports the above restriction, we will make corresponding adaptation.
openGauss Connector Limitations
The following SQL statements are not yet supported: