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:
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
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.