TimesTen

Developer(s)	Oracle Corporation
Stable release	18.1.4
Platform	Cross-platform
Type	Relational database management system
License	Proprietary
Website	TimesTen Home Page

TimesTen is an in-memory, relational database management system with persistence and recoverability. Originally designed and implemented at Hewlett-Packard labs in Palo Alto, California, TimesTen spun out into a separate startup in 1996 and was acquired by Oracle Corporation in 2005.

All data within a TimesTen database is located in physical memory (RAM), which means that no data operation requires disk I/O. This is unlike traditional disk-optimized relational databases such as the Oracle Database, DB2, Informix or SQL Server, whose designs must contain algorithms that attempt to minimize disk accesses. TimesTen provides applications with short, consistent response-times and very high throughput as required by applications with database-intensive workloads.

As memory operates far faster than hard disk, TimesTen is used in applications where service-level agreements require low and predictable response times, such as telecommunications, real-time financial-services trading applications, network equipment, and large web applications. Also, unlike other memory-caching systems that use key-value pairs (such as Memcached, Hazelcast or Coherence), TimesTen can be accessed with standard interfaces such as ODBC and JDBC and provides the functionality of the SQL and PL/SQL languages.

Applications with data residing in an Oracle Database can utilize TimesTen through a database caching option (as distinct from Oracle Database In-Memory), in which TimesTen functions as an in-memory cache database in front of an Oracle Database.

TimesTen runs on most major Unix/Linux platforms and also supports client application running on Windows and macOS.

Technology

TimesTen is an in-memory database that provides very fast data access time. It ensures that all data will reside in physical memory (RAM) during run time. This allows the search and data management algorithms used to be simplified, resulting in very low response times even on commodity hardware.

In-Memory Database

At runtime the data in a TimesTen database is stored in shared memory. The size of a TimesTen database is practically limited only by the amount of RAM available on its host computer, up to terabytes in size.

Application connection modes

Applications access TimesTen databases using standard relational APIs such as ODBC, JDBC, OCI, and ODPI-C. This allows applications to be written in many programming languages. Applications use those APIs to access and manipulate data using standard SQL. Stored procedures can also be implemented and executed using PL/SQL.

Applications may connect to TimesTen databases either in a traditional client/server manner using TCP/IP as the underlying transport or in direct mode. Direct mode allows applications running on the same machine as the database to avoid network stack and context switching overheads. At runtime the data in a TimesTen database is stored in shared memory; this allows application processes to directly attach to the database memory and access it without IPC or context switch overheads. The same APIs and capabilities are available in both modes.

Persistence

Checkpoint and transaction log files

At runtime all TimesTen data exists in RAM, however TimesTen utilizes non-volatile storage for database persistence and recoverability. TimesTen stores snapshots of the database, called checkpoint files, in a local filesystem. In addition all modifications to the database are also recorded in transaction log files. The combination of checkpoint files and transaction log files allow TimesTen to recover the database in the event of a system failure.

In-memory database cache

TimesTen provides the capability to cache data from an Oracle Database source. To utilize Oracle Database caching, one defines one or more SQL objects known as cache groups. A cache group is a set of one or more related database tables and allows for subsets of its rows and/or columns. Database tables in a cache group must each have a defined primary key or a unique index declared across a set of non-nullable columns and must be related in a parent-child hierarchy via primary key-foreign key constraints. SQL predicates can be used to control what data is to be cached.

Once a cache group is defined, the cache group can then be "loaded", allowing Oracle Database data to be cached in TimesTen. Applications can then read from and write to cache groups, and all data modifications will then be synchronized with the corresponding Oracle Database tables.

Event notification

TimesTen provides an event notification mechanism through the transaction log API (XLA). XLA provides functions which allow applications to be notified of data changes occurring in TimesTen tables (and also DDL occurring in the TimesTen database). XLA can also be used in conjunction with materialized views to simplify the process of monitoring changes made to rows spanning multiple tables.

Deployment Modes

TimesTen can be configured in two ways, called TimesTen Classic and TimesTen Scaleout.

TimesTen Classic

TimesTen Classic implements in-memory databases that are implemented on a single machine, but which can be replicated to other machines for high availability. Databases provided by TimesTen Classic provide extremely low latency, as queries do not require any network I/O and all data is local.

The TimesTen Classic replication mechanism enables a highly available system by sending database updates between two or more hosts. Typically an active-standby pair of databases is used for highest availability. In addition to the active and standby databases, multiple subscriber databases can be configured to serve as disaster recovery copies or read-only farms.

TimesTen Scaleout

TimesTen Scaleout allows a single TimesTen database to span many machines. A shared-nothing architecture is used to distribute data across multiple TimesTen instances running on many machines. All machines can query and modify all data in the database, and all database ACID properties are fully supported. Multiple copies of data are kept for high availability. Databases provided by TimesTen Scaleout can be larger than the amount of RAM available on a single machine, and database throughput is scalable as more machines are added.

History

TimesTen was founded in HP labs by Marie-Anne Neimat, Sherry Listgarten, Kurt Shoens and Kevin Wilkerson, under the name of "Smallbase". At HP, Jean-René Bouvier decided to embed Smallbase into HP OpenCall, which made the first commercial use of the product in 1995. In 1996, the product was spun off into a separate venture capital funded startup company based in Mountain View, California under the leadership of CEO Jim Groff. The product became popular for telecommunications equipment, as response times in the milliseconds or even microseconds were required for applications like packet switching. The company had 90 employees and was profitable when it was acquired by Oracle Corporation in 2005. After the acquisition, Neimat remained as the director of TimesTen development at Oracle, adding many Oracle database features to the product such as support for PL/SQL and integration with Oracle SQL Developer and Oracle Enterprise Manager.

External links

• TimesTen Product Website
• TimesTen documentation
• TimesTen Blog
• TimesTen Samples