Examples with ReplicationFactor org.apache.cassandra.locator.ReplicationFactor used on opensource projects

Example 1 with ReplicationFactor

use of org.apache.cassandra.locator.ReplicationFactor in project cassandra by apache.

the class AlterKeyspaceStatement method validateTransientReplication.

private void validateTransientReplication(AbstractReplicationStrategy oldStrategy, AbstractReplicationStrategy newStrategy) {
    // that a good default is to not allow unsafe changes
    if (allow_unsafe_transient_changes)
        return;
    ReplicationFactor oldRF = oldStrategy.getReplicationFactor();
    ReplicationFactor newRF = newStrategy.getReplicationFactor();
    int oldTrans = oldRF.transientReplicas();
    int oldFull = oldRF.fullReplicas;
    int newTrans = newRF.transientReplicas();
    int newFull = newRF.fullReplicas;
    if (newTrans > 0) {
        if (DatabaseDescriptor.getNumTokens() > 1)
            throw new ConfigurationException(String.format("Transient replication is not supported with vnodes yet"));
        Keyspace ks = Keyspace.open(keyspaceName);
        for (ColumnFamilyStore cfs : ks.getColumnFamilyStores()) {
            if (cfs.viewManager.hasViews()) {
                throw new ConfigurationException("Cannot use transient replication on keyspaces using materialized views");
            }
            if (cfs.indexManager.hasIndexes()) {
                throw new ConfigurationException("Cannot use transient replication on keyspaces using secondary indexes");
            }
        }
    }
    // to read from a transient replica as if it were a full replica.
    if (oldFull > newFull && oldTrans > 0)
        throw new ConfigurationException("Can't add full replicas if there are any transient replicas. You must first remove all transient replicas, then change the # of full replicas, then add back the transient replicas");
    // Don't increase transient replication factor by more than one at a time if changing number of replicas
    // Just like with changing full replicas it's not safe to do this as you could read from too many replicas
    // that don't have the necessary data. W/O transient replication this alteration was allowed and it's not clear
    // if it should be.
    // This is structured so you can convert as many full replicas to transient replicas as you want.
    boolean numReplicasChanged = oldTrans + oldFull != newTrans + newFull;
    if (numReplicasChanged && (newTrans > oldTrans && newTrans != oldTrans + 1))
        throw new ConfigurationException("Can only safely increase number of transients one at a time with incremental repair run in between each time");
}