SharePlex® for Oracle

Architecture

SharePlex® for Oracle is a leading data replication solution which allows you to meet your business continuity and performance needs by utilizing a unique technical architecture. SharePlex for Oracle provides asynchronous, fault tolerant, streaming and near real time replication of the Oracle database.

The key benefits of using this architecture

• Maintains a current, available database for multiple uses
• Fast and accurate, imposing virtually no overhead on the production instance
• Scalable and complete, able to replicate business volumes of data now and evolve with your growing needs
• Resilient to common outages
• Facilitates 24x7 operation by helping eliminate planned downtime with the Reconcile option
• For more, see the features and benefits page

Foundation Architecture

The following illustration will provide a basic conceptual understanding of how SharePlex works.

Capture

The SharePlex capture process gathers changes with virtually no overhead on the production database. In the capture process:

• SharePlex reads from the Oracle redo logs, so the process of replication does not add performance loads to the production instance.
• The network transports only changes to replicated objects, (not the rest of the database housekeeping information contained in the redo logs) so the SharePlex network usage is very low and consistent.
• Database resources are not required to capture and move the data. A small repository does reside in Oracle to record information such as when replication started/stopped, etc.
• SharePlex can read the online redo logs, go back through archive logs and even prompt for archive logs which have been taken offline to secondary storage. It is this capability that adds to the fault tolerance. For example, if the capture process is terminated for some reason, it can literally go back in time.

Transport

SharePlex uses its own network protocol combined with TCP/IP to transport data between the source and target systems. The process confirms the receipt and the appropriate order of the network packets, providing fault tolerance for network interruptions while ensuring data integrity and completeness. No additional middleware is required to transport the data.

Posting

The SharePlex post process converts the change information into SQL statements. The SQL statements are then applied to the open target instance using standard SQL*Plus connections. Because SharePlex updates the target instances using standard SQL like any other application, the concern about its supportability from Oracle is unwarranted.

Part of the key to SharePlex' accurate replication is its ability to maintain Oracle's read consistency from source to target, not only replicating the order of the transactions, but also their context. SharePlex replicates the combination of updating transactions to the target as they occurred on the source, so that the resulting replica is reliable for disaster recovery. To accomplish this, SharePlex creates connections to the target database to mirror the updating connections on the source system. This ensures transactions can be applied to the target instance in parallel, as they occurred on the source.

Use Case Scenarios

SharePlex supports a variety of configurations to meet your high availability or load balancing needs. SharePlex is not limited to replicating simply between source A and target B in one direction, although there is tremendous value in this architecture alone. Examples include:

Load Balancing/Reducing Query Contention

Use the up-to-the-minute, fully accessible database for ad hoc querying and reporting to reduce contention and improve performance on your production system. For more information, please see our white paper.

Migrations

Migrations are a major availability challenge that companies face today. Whether your company has undergone a merger or acquisition and is experiencing a related data center consolidation, considering a change in hardware platforms, or about to upgrade Oracle or operating system platforms, SharePlex will allow business to continue while the activities occur. The original system will function as normal but SharePlex will capture and queue all transactions that occur during the migration. For more information, please see our white paper.

High Availability/Disaster Recovery

Today’s enterprise requires constant availability for its data and processes. SharePlex can provide an alternate copy of production data for failover in case a server goes down or if maintenance is required. For more information, please see our white paper.

Distributed Processing

The peer-to-peer configuration enables you to distribute users to different servers, keeping all copies of the database current with changes from each of the other servers. In this configuration, SharePlex applies conflict resolution as required by the circumstance and as defined by your business needs. This scenario provides the fastest possible fail over time that can be achieved using any technology in a wide area network environment for disaster recovery.

Broadcast and Consolidated Replication

SharePlex replicates in real-time over both local area and wide area networks (LAN and WAN) to disseminate copies of production data wherever needed. For broadcast replication, remote users gain access to up-to-date data without logging on to the production server, improving network and OLTP performance.

Data Distribution Across the Globe

If you need to replicate data to a target that is not directly connected, SharePlex supports cascading replication. Using this configuration, for example, you can replicate data between long distances (e.g., from New York to Tokyo.) SharePlex can support numerous complex replication scenarios to meet your needs. In this cascading example, no Oracle software is required on this node if it will only be acting to store and forward.