OODB System ComparisonOODB System Comparison

Presented byPresented by

David BuchananDavid Buchanan

Farhad BarfataniFarhad Barfatani

Matthew BuchananMatthew Buchanan

Mark DowningMark Downing

Systems SelectedSystems Selected

Gemstone

Versant

Object Store

Poet

Jasmine, Objectity/DBand Others

Criteria Selected Criteria Selected Architecture / SchemaArchitecture / Schema Schema EvolutionSchema Evolution VersioningVersioning RecoveryRecovery Concurrency Concurrency PersistencePersistence Programming Languages Programming Languages Support ToolsSupport Tools Query Support Query Support Legacy Support Legacy Support Platform Support Platform Support

ArchitectureArchitecture

VersantVersant JasmineJasmine GemstoneGemstone ObjectStoreObjectStore

Schema EvolutionSchema Evolution

VersantVersant POETPOET ObjectivityObjectivity Object StoreObject Store

VersioningVersioning

VersantVersant JasmineJasmine ObjectivityObjectivity Object StoreObject Store

Versant Version 6.0

Recovery A dual logging feature manages recovery. System maintains physical and logical logs. Roll Forward mechanism is used to recover

the database.

– System’s roll back reapply committed transactions .

Versant Version 6.0

Concurrency

  Persistent locks support long transactions.Persistent locks support long transactions. Short locks are also provided for shorter Short locks are also provided for shorter

transactions.transactions. ““No-locks” for optimistic locking.No-locks” for optimistic locking.

– Users to define their own locks.Users to define their own locks.– Denies locks that would result in a deadlock.Denies locks that would result in a deadlock.

Versant Version 6.0

Concurrency

Persistent locks support long transactions. Short locks are also provided for shorter

transactions. “No-locks” for optimistic locking. Users to define their own locks. Denies locks that would result in a deadlock.

Jasmine

Recovery

Database log files for Non-catastrophic failure.

Journaling in the event of catastrophic failure.

Jasmine

Recovery

Journal files are backups of the entire database.

Journaling does not include backing up of multimedia files.

Facilities allow full and partial backups to be done online or offline.

Jasmine

Recovery

Database can perform incremental backups of the database.

» It uses a circular log file.» Logs used to roll forward to the last

processed transactions» To restore backed up copy requires system

shut down.

JasmineJasmine

Concurrency

Jasmine uses a combination of:» Object locking

» Versioning

for concurrency control.

JasmineJasmine

Concurrency

Jasmine support:– Database Locking– Store Locking– Class Locking– Page Locking– Object Locking

GemStoneGemStone

Recovery

Network or hardware failure recovery Replication. Backup. Logging mechanisms.

GemStoneGemStone

Recovery

Restoration after disk or system failure: Full backup. Using log files. Transaction logs.

GemStoneGemStone

Concurrency

Transaction mechanisms control concurrency.– It uses optimistic locking.

POET

Recovery

Roll forward recovery mechanism using logs.

Supports an external backup facility. Backed up while clients still use the

database.

POET

Concurrency

Concurrency control is managed by using: Nested transactions. Locks.

Locks prevent reading, updating or deleting of objects by unauthorized users.

ObjectivityObjectivity

Recovery

Inbuilt recovery mechanism. Automatic Recovery:

– Application;

– Local server;

– Remote server host;

– Lock server host;

– Process failures.

ObjectivityObjectivity

Concurrency

Concurrent access: Flexible transaction model. Multiple readers, one writer. Object-level versioning. Hierarchical locking. Lock waiting. Active deadlock detection across databases.

ObjectivityObjectivity

Concurrency

Concurrent access:

Flexible transaction model. Multiple readers, one writer. Object-level versioning. Hierarchical locking. Lock waiting. Active deadlock detection across databases.

ObjectstoreObjectstore

Recovery

Transaction logging Two-phase commit

ObjectstoreObjectstore

Concurrency

Multi-Version Concurrency Control (MVCC )

MVCC can be applied selectively to individual databases, or to entire servers.

Persistence & Programming Persistence & Programming LanguagesLanguages

Versant– Java– C++

Jasmine– Java– C/C++– ActiveX

GemStone– Smalltalk– Java

Persistence & Programming Persistence & Programming LanguagesLanguages

POET– Java– C++

Objectivity– Java– Smalltalk– C++– SQL++

ObjectStore– Java– C/C++– ActiveX

Query SupportQuery Support

OQLOQL– Object StoreObject Store– VersantVersant

ODQLODQL– JasmineJasmine

Legacy SupportLegacy Support

Relational Database SupportRelational Database Support– ObjectivityObjectivity– VersantVersant– JasmineJasmine

ConclusionConclusion

OODB’s StrengthsOODB’s Strengths Which is the best system?Which is the best system?