Package org.apache.solr.cloud

Class ZkDistributedCollectionLockFactory

java.lang.Object

org.apache.solr.cloud.ZkDistributedCollectionLockFactory

All Implemented Interfaces:

DistributedCollectionLockFactory

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 Summary

Constructors

Constructor	Description
ZkDistributedCollectionLockFactory(org.apache.solr.common.cloud.SolrZkClient zkClient, String rootPath)

Method Summary

Modifier and Type	Method	Description
DistributedLock	createLock(boolean isWriteLock, org.apache.solr.common.params.CollectionParams.LockLevel level, String collName, String shardId, String replicaName)	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.
protected DistributedLock	doCreateLock(boolean isWriteLock, String lockPath)
protected StringBuilder	getPathPrefix()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

ZkDistributedCollectionLockFactory

public ZkDistributedCollectionLockFactory(org.apache.solr.common.cloud.SolrZkClient 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

Parameters:

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

Returns:

a lock instance that must be DistributedLock.release()'ed in a finally, regardless of the lock having been acquired or not.

doCreateLock

protected DistributedLock doCreateLock(boolean isWriteLock,
                                       String lockPath)

getPathPrefix

protected StringBuilder getPathPrefix()