Replicate your Key Value Store across your network, with consistency, persistance and performance.
Ultra low latency: Chronicle Map targets
median latencyof both read and write queries of
less than 1 microsecondin certain tests.
Write queries scale well upto the number of hardware execution threads in the server.
Read queries never blockeach other.
Persistence to disk - (Optional)
Multi-master replication - (Optional,
fully-redundant, asynchronous replication across servers,
"last write wins"strategy by default, allows to implement custom state-based CRDT(conflict-free replicated data type) strategy.The writer can optionally wait for replication to occur across nodes or regions.
In-memory off-heap Map
Persistence to disk
Eventually-consistent replication (100% redundancy
Entry expiration timeouts
What guarantees does Chronicle Map provide in ACID terms?
Atomicity - single-key queries are atomic if Chronicle Map is properly configured, multi-key queries are not atomic.
Consistency - doesn’t make sense for key-value stores
yes; for both single- and multi-key queries.
no; Chronicle Map can be persisted to disk, but with no guarantee as to how frequently this happens. This is under the control of the OS. All data is guaranteed to be written to disk when the Map is closed.
Clustering and replication for Chronicle Map is provided by Chronicle Map Enterprise.
What is the data structure of Chronicle Map?
Simply put, a Chronicle Map data store is a big chunk of shared memory (optionally mapped to disk).
It is split into independent segments; each segment has:
an independent memory allocation for storing the entries
a hash table for search
a lock in shared memory (implemented via CAS loops) for managing concurrent access.
See Chronicle Map data store design overview for more information.
Chronicle Map does not support:
iteration over the entries in alphabetical order.
sorting of keys.
LRU entry eviction.
Multiple processes can access a Chronicle Map concurrently. At the same time, the data store is in-process for each of the accessing processes. Out-of-process approach to IPC is simply incompatible with Chronicle Map’s median latency target of < 1 μs.
Replication without logs, with constant footprint cost, guarantees progress even if the network doesn’t sustain write rates.
Other key points
size not limited by memory The size of a Chronicle Map is not limited by memory (RAM), but rather by the available disk capacity.
Eventually-consistent replication (100% redundancy) Commercially available
Clustering and replication Commercially available
Do not use it in your production application.
If you have more time, you can clone and read the source code or take exercise.