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Transparent Persistence
+ Transaction Processing…
Smalltalk is pure object-oriented programming for complex business and technical applications, but these benefits can be lost in the mismatch between language and database. The VOSS open source database management system extends Smalltalk with persistent virtual object storage, transparent access and transaction management.
- Multi-process, multi-image & multi-machine access to distributed objects
- ACID transactions with logging and rollforward crash recovery
- Continuation Transactions manage multiple web page states & what-if futures (v3.1)
- Web server / application process rendezvous (v3.1)
- Automatic object locking and transaction retry on time-out
- Automatic object change detection, no lock conflicts with sub-transactions
- Multi-key/multi-value Btree DictionarySet and other virtual collections
- Time-slice MVRC repeatable read and MVCC with short read-locks
- Distributed copying, parented copying, identity-exchange, object checkout etc.
- Concurrent background & foreground garbage collection
- Terabyte 64-bit object id and addressing default, configurable up to 128-bit
- Dual Licensing - Open Source GPLv3 and Supported Commercial
…Seamless Smalltalk Solutions
‘Garbage’, in an object-oriented database system, means objects which have become unreachable because references from other objects have been removed by the application, and which are therefore to be removed to reclaim storage space. The garbage collector (’GC’) in VOSS is a ‘Baker’ design, similar in concept to the garbage collector in Smalltalk-80, which can be run in foreground and/or background modes of which more later.
Unlike the mark-sweep design, which truly is a ‘garbage collector’, the Baker design would be better characterised as a ‘good object preserver’ which copies all reachable objects within a virtual space back and forth from one ’semi-space’ to another, deleting everything left behind on each flip. This has consequences for database design, administration, and the choice of GC settings, to tune for maximum transaction throughput and minimum time offline.
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on this post Where do you keep your behavior? Normalised in the application domain objects? In non-domain transaction-performing classes? Some of each? I seem to remember this question being touched on once long ago in Digitalk’s Compuserve forum, but never since. Read the rest of this entry »
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