6.2.1 Release Notes

SuspectExceptions are raised when nodes are shutting down, which is normal and expected, since a suspect node is an unresponsive node. As a result, a SuspectException ERROR is written in the logs. There is currently no fix for this issue. The SuspectExceptions will not be logged in a future version of Red Hat JBoss Data Grid. The SuspectExceptions do not affect data integrity.

Using special characters in directory paths can cause problems when starting Red Hat JBoss Data Grid server. The JBoss Data Grid server either fails to start or a configuration file for logging capabilities cannot be loaded properly. Special characters include spaces, # (hash sign), ! (exclamation mark), % (percentage sign), $ (dollar sign). This bug causes the JBoss Data Grid server to fail to start properly.Avoiding the use of special characters will stop this problem occurring, allowing JBoss Data Grid server to start properly.

When a site is unreachable, JGroups's RELAY2 logs error for each dropped message. Infinispan has configurable fail policies (ignore/warn/abort), and even with ignore policy the log is filled with errors.

When a Map/Reduce task is executed against a cache with many small values, the task may experience TimeoutExceptions while trying to write the intermediate results to the cache.As a result, when these exceptions occur, the task fails.

There are several things the user can do to try and alleviate this issue:

In distributed cache mode with L1 enabled and onRehash=true, when an entry is overwritten during state transfer, the overwrite may be ignored. This node will then report an outdated value of the entry, and after L1 timeout this entry will be completely removed.

As a workaround, use L1 with onRehash=false.

Sending a message through JGroups may fail under some race conditions with ArrayOutOfBoundException. The reliability mechanism will try to resend this message again, but all these subsequent attempts will fail with NullPointerException.

Therefore, the message will be never received on the receiver node and will be held in unacknowledged messages buffer on the sender node. If this message is ordered within JGroups, no more ordered messages from this node will be delivered on the receiver node. Some following messages may be buffered as well, eventually leading to OutOfMemoryException.

It is recommended to use UNICAST3 as this dramatically reduces the chance of this bug to happen (it was observed with UNICAST2).

When REPEATABLE_READ isolation mode is enabled, reading values from AtomicMap and FineGrainedAtomicMap is not consistent within the same transaction. If another thread changes the value during the transaction, the new value is reflected immediately in the current thread while the thread should still see the original value.

The writeSkewCheck flag does not work correctly for AtomicMap. When JBoss Data Grid runs in REPEATABLE_READ isolation mode for transactions, the writeSkewCheck flag is enabled, and two concurrent transactions read/write data from the same AtomicMap. The WriteSkewException exception is never thrown when committing either of the transactions.

Consequently, the data stored in the AtomicMap might be changed by another transaction, and current transaction will not register this change during commit.

By default, the C++ Hot Rod client resolves server host names using IPv4 addresses. If a server is listening on an IPv6 address, the client will not be able to connect to it. Either specify the server using its IP instead of the name or set the HOTROD_IPSTACK environment variable to IPV4 or IPV6 to force resolution using the preferred stack. The client will connect to the specified server.

If a cluster is no longer reachable for some reason, i.e. network disconnect, the hot-rod client tries to re-establish the lost connections. The client library will retry this by a fixed calculation based on the max numbers of connections from the pool, or 10 multiplied with the number of available servers. This may result in a long delay until the application can continue and react, as it will wait for the read timeout for each try.

This has been fixed by adding a new configuration property infinispan.client.hotrod.max_retries. This property defines the maximum number of retries in case of a recoverable error. A valid value should be greater or equal to 0 (zero). Zero means no retry. Default is 10.

If a Hot Rod client is connected to a server cluster and one of the servers is shutdown gracefully, the client keeps trying to reconnect to the server. This occurs in replicated mode. There is no failure from the application perspective but there is always a retry if the RoundRobin strategy returns the unavailable server. This might have impact on performance or even cause a failure if there is a larger cluster and a part is going out of work for some reason.

Configuring an asynchronous cache store with 'preload' enabled leads to pre-loading each entry in the store in a loop, each entry being loaded through a store read. This has been fixed. Pre-loading entries from a cache store is now more efficient and does not require loading each entry through a store read.

L1 cache in distributed mode with concurrent gets originating from the same node for the same key can result in one being stuck if there is no value found. This can cause massive degradation of performance as the request would never complete.

The CACHE_MODE_LOCAL flag does not force the EntryWrappingInterceptor to wrap the entry. As a result, the entry will not be stored in the non-transactional cache if the current node is not the primary owner of the entry. This has been fixed for replicated mode. In distributed mode, such an operation stores the entry in L1 cache if it is enabled. If L1 cache is disabled and current node is not the primary owner of the entry, then this is a no-operation.

The format of pre-signed URLs has changed on Amazon Web Services. All pre-signed URLs must now include the bucket name in the hostname. As a result, Red Hat JBoss Data Grid does not work correctly on Amazon Web Services when pre-signed URLs are used. To fix this, change the URL parsing code in S3_PING JGroups protocol to allow S3_PING to work in AWS. As a result, JBoss Data Grid works correctly on Amazon Web Services when pre-signed URLs are used.

Configuring an indexed cache with 'infinispan' as a directory provider for Lucene will result in an exception at server startup due to missing dependencies. It is not possible to use 'infinispan' as a directory provider for Lucene with Remote Query. Dependencies have been added to the server modules which corrected the functionality.

org.infinispan.query.dsl.Query.getResultSize() was giving wrong results when used in remote mode as a Remote Query.

SingleKeyNonTxInvocationContext.addLockedKey() only sets a isLocked flag, the actual key is set when the entry is wrapped and inserted in the context. If the topology changes between the lock acquisition and the entry wrapping, SingleKeyNonTxInvocationContext.getLockedKeys() will return an empty set and the lock will not be released. Future commands will not try to acquire a lock on this node, so the stale lock is harmless most of the time. However, if there was already a command waiting for the lock, that command will time out (instead of retrying on the new primary owner).

To fix this issue, set the actual key and isLocked flag on SingleKeyNonTxInvocationContext at the same time. Furthermore, prevent from incorrect returning the empty set of keys so that keys can be properly unlocked. As a result, locks are properly released during state transfer and commands do not time out due to locks being held.

Future object returned from an async operation on RemoteCache (such as getAsync(key)) allows it to register a listener for the operation completion. When the operation executes very quickly, there is a chance that the client code did not registered the listener yet. In that case, the listener is not called at all. As a result, when the listener is executed (the situation above does not happen), calling get() on the future returned from getAsync() causes a deadlock, the call does not return and the thread executing the listener is blocked forever.

The configuration schema for library mode of Red Hat JBoss Data Grid does not allow to you enable the "preload" and "shared" attributes of a JDBCCacheStore. As a result, JDBCCacheStore can not be configured to preload data from a relational database on startup or to be used as a shared cache store. This only applies to caches being configured through XML configuration files. The respective functionality is available when JBoss Data Grid is configured through Java API.

The configuration file for library mode is now parsed correctly so that "preload" and "shared" attributes are properly set.

The implementation of FileEntry.compareTo() is incorrect in that it never returns 0. As a result, entries are not properly removed from the list of removed/expired entries which is held by the SingleFileStore. Such entries are supposed to be re-used and their space on file system used for newly created entries. Due to this bug, newly created entries are always appended at the end of the file, not freeing up the space occupied by entries removed/expired earlier.

The server configuration files now contain an additional JGroups stack that makes it possible to run Red Hat JBoss Data Grid on Amazon Web Services as a cluster. The stack is called "s3" and includes S3_PING JGroups protocol for discovering new nodes in the cluster.

When RemoteCacheManager is configured with connectionPool and minIdle attribute greater than zero, and there are multiple instances of JDG server which are clustered, a segmentation fault (Segfault) is raised during runtime. This has been fixed and the segmentation fault no longer occurs.

Setting custom JDBC store properties causes an exception to be thrown. This has been fixed and it is now possible to configure JDBC cache store with custom properties such as databaseType.

Configuration of a generic cache loader from JBoss ON fails with exception "org.infinispan.persistence.cluster.ClusterLoader is not a valid cache loader". This is caused by the fact that the configuration parser incorrectly casts every custom cache loader class to an older cache loader API (pre-JBoss Data Grid 6.2 API). This has been fixed and it is now possible to configure a generic cache loader from JBoss ON.

Configuration of a generic cache store from JBoss ON fails. Generic cache store have the limitation that the ConfigurationBuilder for the store must be in the same Java package as the store itself. This has been fixed and it is now possible to configure a generic cache store from JBoss ON, even if the ConfigurationBuilder is in a different package.

The method keySet() of remote client fails on distributed caches with indexing enabled. This is caused but the fact that a ClassCastException is thrown in the map-reduce task that collects the keys across the cluster. The task expects the cached value to by byte[], which is not the case if protobuf marshalling is used. The value is never used by the task, so avoiding the unnecessary casting also avoids this issue.