TimesTen Scaleout Features

In-Memory Database

A database in TimesTen is a memory-optimized relational database that empowers applications with the responsiveness and high throughput required by today's enterprises and industries. Databases fit entirely in physical memory (RAM) and provide standard SQL interfaces.

TimesTen is designed with the knowledge that all data resides in memory. As a result, access to data is simpler and more direct resulting in a shorter code path and simpler algorithms and internal data structures. Thus, TimesTen delivers performance by optimizing data residency at run time. By managing data in memory and optimizing data structures and access algorithms accordingly, database operations run with maximum efficiency, achieving dramatic gains in responsiveness and throughput.

Performance

TimesTen Scaleout achieves high performance by distributing the data of each database across instances in the grid in a shared-nothing architecture. TimesTen Scaleout spreads the work for the database across those instances in parallel, which computes the results of your SQL statements faster.

Persistence and Durability

Databases in TimesTen are persistent across power failures and crashes. TimesTen accomplishes this by periodically saving to a file system:

All data through checkpoint files.
Changes made by transactions through transaction log files.

In TimesTen Scaleout, the data in your database is distributed into elements. Each element keeps its own checkpoint and transaction log files. As a result, the data stored in each element is independently durable. Each instance in a grid manages one element of a database. In the event of a failure, an instance can automatically recover the data stored in its element from the checkpoint and transaction logs files while the remaining instances continue to service applications.

TimesTen Scaleout also enables you to keep multiple copies of your data to increase durability and fault tolerance.

You can change the durability settings of a database according to your performance and data durability needs. For example, you may choose if data is flushed to the file system with every commit or periodically in batches in order to operate at a higher performance level.

SQL and PL/SQL Functionality

Applications use SQL and PL/SQL to access data in a database. Any developer familiar with SQL can be immediately productive developing applications with TimesTen Scaleout.

For more information on SQL, see Using SQL in TimesTen Scaleout and Oracle TimesTen In-Memory Database SQL Reference. For more information on PL/SQL, see Table 1-9 and Oracle TimesTen In-Memory Database PL/SQL Developer's Guide.

Transactions

TimesTen Scaleout supports transactions that provide atomic, consistent, isolated and durable (ACID) access to data. See Understanding Distributed Transactions in TimesTen Scaleout and Transaction Management in Oracle TimesTen In-Memory Database Operations Guide.

Scalability

TimesTen Scaleout enables you to transparently distribute the data of a database across multiple instances, which are located on separate hosts, to dramatically increase availability, performance, storage capacity, processing capacity, and durability. When TimesTen Scaleout distributes the data of your database across multiple instances, it uses the in-memory resources provided by the hosts running those instances.

TimesTen Scaleout enables you to add or remove instances in order to control both performance and the storage capacity of your database. Adding instances expands the memory capacity of your database. It also improves the throughput of your workload by providing the additional computing resources of the hosts running those instances. If your business needs change, then removing instances (and their hosts) enables you to meet your targets with fewer resources.

Data Transparency

While TimesTen Scaleout distributes your data across multiple instances, applications do not need to know how data is distributed. When an application connects to any instance in the grid, it has access to all of the data of the database without having to know where specific data is located.

Knowledge about the distribution of data is never required in TimesTen Scaleout, but it can be used to tune the performance of your application. You can use this knowledge to exploit locality where possible. See Using Pseudocolumns.

High Availability and Fault Tolerance

TimesTen Scaleout automatically recovers from most transient failures, such as a congested network. TimesTen Scaleout recovers from software failures by recovering from checkpoint and transaction log files. Permanent failures, such as hardware failures, may require intervention by the user.

TimesTen Scaleout provides high availability and fault tolerance when you have multiple copies of data located across separate hosts. TimesTen Scaleout provides a feature called K-safety (k) where the value you set for k during the creation of the grid defines the number of copies of your data that will exist in the grid. This feature ensures that your database continues to operate in spite of various faults, as long as a single copy of the data is accessible.

To have only a single copy of the data, set k to 1. This setting is not recommended for production environments.
To have two or more copies of the data, set k to 2 or greater (the maximum supported value is 5). A grid can be fault tolerant with this setting. Thus, if one copy fails, one or more copies of the data exists. Ensure you locate each copy of the data on distinct physical hardware for maximum data safety.

TimesTen Scaleout provides fault tolerance for both software and hardware failures:

Software failures are often transient. When one copy of the data is unavailable due to a software error, SQL statements are automatically redirected to the other copy of the data (if possible). In the meantime, TimesTen Scaleout synchronizes the data on the failed system with the rest of the database. TimesTen Scaleout does not require any user intervention to recover as long as the instances are still running.
Hardware failures may eventually require user intervention. In some cases, all that is required is to restart the host.

TimesTen Scaleout provides a membership service to help resolve failures in a consistent manner. The membership service provides a consistent list of instances that are up. This is useful if a network error splits the hosts into two separate groups that cannot communicate with each other.

Centralized Management

You do not need to log onto every host within a grid in order to perform management activities. Instead, you conduct all management activity from a single instance using the ttGridAdmin utility. The ttGridAdmin utility is the main utility you use to define, deploy, and check on the status of each database.

You can also use the ttGridRollout utility or the Oracle SQL Developer GUI (both of which use the ttGridAdmin utility under the covers to process all requests) to facilitate creating, deploying, and managing your grid:

If you are creating a grid for the first time, you can use the ttGridRollout utility to define and deploy your grid. After creation, use either the ttGridAdmin utility or Oracle SQL Developer to manage your grid.
You can create and manage any grid using Oracle SQL Developer, which is a graphical user interface (GUI) tool that gives database developers a convenient way to create, manage, and explore a grid and its components. You can also browse, create, edit, and drop particular database objects; run SQL statements and scripts; manipulate and export data; and view and create reports. See Oracle TimesTen In-Memory Database SQL Developer Support User's Guide.