TimesTen

TimesTen is an in-memory, relational OLTP database management system supporting SQL through Open Database Connectivity (ODBC), Java Database Connectivity (JDBC) and Oracle Call Interface (OCI) APIs. It services very well for real time application because of short response time and high throughput derived from its in-memory characteristics. TimesTen can deployed in following ways: Classic (single node), Cache and Scaleout (distributed, assume this deployment when coming to concurrency-related sections later).

History

TimesTen was originally named as SmallBase and developed by HP Labs. Shortly after its first commercial use in 1995, the product was split out as a separate startup company and renamed as TimesTen. In 2005, the company with 90 employees at the time was acquired by Oracle. TimesTen was then integrated with Oracle software as well as services and become part of Oracle Database Products.

Checkpoints

Non-Blocking Blocking Fuzzy

TimesTen maintains two checkpoint files (ds0 and ds1) on disk to keep track of metadata of in-memory permanent data. It switches two files when a checkpoint is done to ensure there is always at least one completed checkpoint file for backup and recovery purpose. The rate for checkpointing disk writes is configurable by application. It supports fuzzy or non-blocking checkpoints as well as transaction-consistent checkpoints (i.e. blocking checkpoints).

Concurrency Control

Multi-version Concurrency Control (MVCC) Two-Phase Locking (Deadlock Detection)

Concurrency control of TimesTen is achieved through isolation and locking. It supports fully ACID transactions but allow user to loose it for performance by modifying configuration.

Locking

TimesTen provides three level of lock granularity: row-level, table-level and database-level. By default, row-level locking is used to maximize the throughput. TimesTen has lockless multi-versioning mechanism for read-write concurrency and uses row-level locking to ensure write-write concurrency.

Deadlock Detection

Deadlock detection is supported in TimesTen with a subdaemon process checking every 2 seconds. It reports and eliminates deadlock when the situation occurs. Application should roll back and retry entire transaction when it is denied a lock due to deadlock error.

Isolation Levels

Read Committed Serializable

Data Model

Relational

TimesTen implements actual relational data model instead of just a relational view. Data in TimesTen is stored as tables of rows which contains data fields.

Storage Architecture

In-Memory

Compression

Dictionary Encoding

TimesTen supports columnar compression. This feature uses dictionary-based encoding to replace column values with dictionary table identifiers. It maintains separate dictionary for each column.

Foreign Keys

Supported

TimesTen supports foreign keys with proper constraints according to relational database model. Each table may have one or more foreign keys to reference columns in other tables. Foreign key feature is performed through range index. Specific constraints implemented in TimesTen for foreign key can be read in documentation of FOREIGN KEY.

Query Interface

SQL

Indexes

B+Tree Hash Table BitMap T-Tree

TimesTen originally used T-Tree indexes as default. Later version of TimesTen moved to range indexes (B+Tree) and supports also hash and bitmap indexes upon request.

System Architecture

Shared-Nothing

TimesTen Logo
Website

http://www.oracle.com/us/products/database/timesten/index.html

Tech Docs

https://docs.oracle.com/database/timesten-18.1/

Developer

HP Labs

Country of Origin

US

Start Year

1996

Former Name

SmallBase

Acquired By

Oracle

Project Type

Commercial

Supported languages

PL/SQL, SQL

Operating Systems

Linux, Windows

Licenses

Proprietary

Wikipedia

https://en.wikipedia.org/wiki/TimesTen