Isolation Levels

Read Committed Serializable

InfinityDB 1.0 transactionality provides no isolation. For InfinityDB 2.0, it supports Serializable and Read Committed transaction isolation modes.

System Architecture

Embedded

Logging

Not Supported

InfinityDB 1.0 and 2.0 requires no log. The single infinityDB data file contains the transactionality. A 'Copy on Write' style system of InfinityDB supports global atomicity, rollback capability and durability

Compression

Bit Packing / Mostly Encoding Prefix Compression

InfinityDB can achieve high compression on disk and in memory. ZLib is used for compressing common substrings and small values are compressed by ZLib's Huffman coding to reduce block-internal free space. Furthermore, prefix and suffix compression are used. Furthermore, prefix and suffix compression are used to remove common-prefixes in keys and common suffixes in upper tree levels. Other compression methods including variable-length concatenations of primitives and variable-length encoded Java primitives are used as well.

Concurrency Control

Optimistic Concurrency Control (OCC)

InfinityDB 1.0 only has 'ACD' features and uses a single global transaction. Any data store modification in the system will be visible to all threads. No lock is used and one global transaction is effected all the time. InfinityDB 2.0 adds transparent multi-Threaded transactionally and the global transaction of InfinityDB 1.0 is also available. The system uses optimistic locking and the optimistic protocol is two-phase. If one transaction of a particular thread has held one lock and another transaction of another thread requests this lock. The existing locks of the requester are all released, the transaction is reset to the not-in-progress state and changes are rolled back. InfinityDB does not use pessimistic locking to guarantee there is no probability of deadlocks.

Data Model

Relational Key/Value Graph Hierarchical Array / Matrix

InfinityDB supports a rich data representation space. ItemSpace is the lowest-level data model containing a set of Items. The basic data model can be used to define huge spare arrays, matrix, any mixture of trees, graphs, key/value maps, key/value maps or user-defined structures.

Indexes

Bw-Tree

InfinityDB supports B-tree. The B-tree is proprietary lockless and concurrent. For each level of the B- Tree, there is one Meta Index used to find a B-Tree cell quickly.