22.9. Other Management Tools and Operations
22.9.1. Accessing Data via URLs
put() and post() methods place data in the cache, and the URL used determines the cache name and key(s) used. The data is the value placed into the cache, and is placed in the body of the request.
GET and HEAD methods are used for data retrieval while other headers control cache settings and behavior.
Note
22.9.2. Limitations of Map Methods
size(), values(), keySet() and entrySet(), can be used with certain limitations with Red Hat JBoss Data Grid as they are unreliable. These methods do not acquire locks (global or local) and concurrent modification, additions and removals are excluded from consideration in these calls.
From Red Hat JBoss Data Grid 6.3 onwards, the map methods size(), values(), keySet(), and entrySet() include entries in the cache loader by default whereas previously these methods only included the local data container. The underlying cache loader directly affects the performance of these commands. As an example, when using a database, these methods run a complete scan of the table where data is stored which can result in slower processing. Use Cache.getAdvancedCache().withFlags(Flag.SKIP_CACHE_LOAD).values() to maintain the old behavior and not loading from the cache loader which would avoid the slower performance.
In JBoss Data Grid 6.3 the Cache#size() method returned only the number of entries on the local node, ignoring other nodes for clustered caches and including any expired entries. While the default behavior was not changed in JBoss Data Grid 6.4 or later, accurate results can be enabled for bulk operations, including size(), by setting the infinispan.accurate.bulk.ops system property to true. In this mode of operation, the result returned by the size() method is affected by the flags org.infinispan.context.Flag#CACHE_MODE_LOCAL, to force it to return the number of entries present on the local node, and org.infinispan.context.Flag#SKIP_CACHE_LOAD, to ignore any passivated entries.
In JBoss Data Grid 6.3, the Hot Rod size() method obtained the size of a cache by invoking the STATS operation and using the returned numberOfEntries statistic. This statistic is not an accurate measurement of the number of entries in a cache because it does not take into account expired and passivated entries and it is only local to the node that responded to the operation. As an additional result, when security was enabled, the client would need the ADMIN permission instead of the more appropriate BULK_READ.
SIZE operation, and the clients have been updated to use this operation for the size() method. The JBoss Data Grid server will need to be started with the infinispan.accurate.bulk.ops system property set to true so that size can be computed accurately.
