Class ZkDistributedCollectionLockFactory

  • All Implemented Interfaces:

    public class ZkDistributedCollectionLockFactory
    extends Object
    implements DistributedCollectionLockFactory
    A distributed lock implementation using Zookeeper "directory" nodes created within a collection znode hierarchy, for use with the distributed Collection API implementation. The locks are implemented using ephemeral nodes placed below the "directory" nodes.
    See Also:
    Zookeeper lock recipe
    • Constructor Detail

      • ZkDistributedCollectionLockFactory

        public ZkDistributedCollectionLockFactory​( zkClient,
                                                  String rootPath)
    • Method Detail

      • createLock

        public DistributedLock createLock​(boolean isWriteLock,
                                          org.apache.solr.common.params.CollectionParams.LockLevel level,
                                          String collName,
                                          String shardId,
                                          String replicaName)
        Description copied from interface: DistributedCollectionLockFactory
        Create a new lock of the specified type (read or write) entering the "competition" for actually getting the lock at the given level for the given path i.e. a lock at collName or a lock at collName/shardId or a lock at collName/shardId/replicaName, depending on the passed level.

        The paths are used to define which locks compete with each other (locks of equal paths compete).

        Upon return from this call, the lock has not been acquired but the it had entered the lock acquiring "competition", and the caller can decide to wait until the lock is granted by calling DistributedLock.waitUntilAcquired().
        Separating the lock creation from lock acquisition allows a more deterministic release of the locks when/if they can't be acquired.

        Locks at different paths are independent of each other, multiple DistributedLock are therefore requested for a single operation and are packaged together and returned as an DistributedMultiLock, see CollectionApiLockFactory.createCollectionApiLock(org.apache.solr.common.params.CollectionParams.LockLevel, java.lang.String, java.lang.String, java.lang.String).

        Specified by:
        createLock in interface DistributedCollectionLockFactory
        isWriteLock - true if requesting a write lock, false for a read lock.
        level - The requested locking level. Can be one of:
        • CollectionParams.LockLevel.COLLECTION
        • CollectionParams.LockLevel.SHARD
        • CollectionParams.LockLevel.REPLICA
        collName - the collection name, can never be null as is needed for all locks.
        shardId - is ignored and can be null if level is CollectionParams.LockLevel.COLLECTION
        replicaName - is ignored and can be null if level is CollectionParams.LockLevel.COLLECTION or CollectionParams.LockLevel.SHARD
        a lock instance that must be DistributedLock.release()'ed in a finally, regardless of the lock having been acquired or not.