Chapter 17. Remote Querying
Red Hat JBoss Data Grid's Hot Rod protocol allows remote, language neutral querying.
Two features allow this to occur:
The Infinispan Query Domain-specific Language (DSL)
JBoss Data Grid uses its own query language based on an internal DSL. The Infinispan Query DSL provides a simplified way of writing queries, and is agnostic of the underlying query mechanisms. Querying via the Hot Rod client allows remote, language-neutral querying, and is implementable in all languages currently available for the Hot Rod client.
The Infinispan Query DSL is essential for performing remote queries, but can be used in both embedded and remote mode.
Protobuf Encoding
Google's Protocol Buffers is used as an encoding format for both storing and querying data. The Infinispan Query DSL can be used remotely via the Hot Rod client that is configured to use the Protobuf marshaller. Protocol Buffers are used to adopt a common format for storing cache entries and marshalling them.
Remote clients that need to index and query their stored entities must use the Protobuf encoding format. It is also possible to store Protobuf entities for the benefit of platform independence without indexing enabled if it is not required.
17.1. Querying Comparison
In Library mode, both Lucene Query-based and DSL querying is available. In Remote Client-Server mode, only Remote Querying using DSL is available. The following table is a feature comparison between Lucene Query-based querying, Infinispan Query DSL and Remote Querying.
| Feature | Library Mode/Lucene Query | Library Mode/DSL Query | Remote Client-Server Mode/DSL Query |
|---|---|---|---|
| Indexing |
Mandatory
|
Optional but highly recommended
|
Optional but highly recommended
|
|
Index contents
|
Selected fields
|
Selected fields
|
Selected fields
|
| Data Storage Format |
Java objects
|
Java objects
|
Protocol buffers
|
| Keyword Queries |
Yes
|
No
|
No
|
| Range Queries |
Yes
|
Yes
|
Yes
|
| Fuzzy Queries |
Yes
|
No
|
No
|
| Wildcard |
Yes
|
Limited to like queries (Matches a wildcard pattern that follows JPA rules).
|
Limited to like queries (Matches a wildcard pattern that follows JPA rules).
|
| Phrase Queries |
Yes
|
No
|
No
|
| Combining Queries |
AND, OR, NOT, SHOULD
|
AND, OR, NOT
|
AND, OR, NOT
|
| Sorting Results |
Yes
|
Yes
|
Yes
|
| Filtering Results |
Yes, both within the query and as appended operator
|
Within the query
|
Within the query
|
| Pagination of Results |
Yes
|
Yes
|
Yes
|
| Continuous Queries | No | Yes | Yes |
| Query Aggregation Operations | No | Yes | Yes |
