6.4.9.RDF Specifics

To set up fault tolerant RDF storage, one can use the template provided in the clrdfdup.sql file in the distribution.

The below applies to testing with prerelease 06.00.3116.The fault tolerance function in 6.00.3116 is provided as a demonstration of concept exclusively and is not intended for production use and has not been tested in production. The below steps will demonstrate the basic capability but one should not try things not explicitly mentioned.

The test starts with an empty database. Edit the create cluster statement in the clrdfdup.sql file to correspond to the setup at hand. Then load the file:

SQL> load clrdfdup.sql;
SQL> cl_exec ('checkpoint');

Now load data. The load will be non-transactional but now will keep two copies of each partition. Use log_enable (2) and ttlp or rdf_load_db..rdfxml as described in the relevant documentation.

After some data is loaded, do another checkpoint.

SQL> cl_exec ('checkpoint');

You may query the data. Now shut down one of the servers. Querying should remain possible as long as one host in each group is online. Start the previously stopped host and stop of another from the same group. Querying remains possible.

Do not try non-transactional loading when all hosts are not online. This produces incorrect results. Do not stop hosts during non-transactional loading. This also produces inconsistent results.

Transactional loading is safe for stopping servers during loading but will stop the loading with an error. The removed host must be either brought back online or removed with cl_host_enable for the loading to proceed.

Do not test transactional RDF loading with 6.00.3116. This version is tested for duplicate partitions with SQL data but incompletely with RDF.