{"id":2378,"date":"2016-08-31T18:52:52","date_gmt":"2016-08-31T18:52:51","guid":{"rendered":"https:\/\/www.couchbase.com\/blog\/?p=2378"},"modified":"2025-10-09T07:21:59","modified_gmt":"2025-10-09T14:21:59","slug":"new-couchbase-mobile-v1-3-inter-instance-replication-sync-gateway","status":"publish","type":"post","link":"https:\/\/www.couchbase.com\/blog\/new-couchbase-mobile-v1-3-inter-instance-replication-sync-gateway\/","title":{"rendered":"New in Couchbase Mobile v1.3: Inter-instance Replication in Sync Gateway"},"content":{"rendered":"

\"DNA<\/h2>\n

DNA undergoing replication.<\/p>\n

Graphic courtesy of Madprime<\/a> with permission under license CC BY-SA 2.0<\/a><\/p>\n

Sync Gateway<\/h2>\n

Sync Gateway<\/a>\u00a0forms the “glue” between\u00a0Couchbase Lite<\/a>\u00a0and\u00a0Couchbase Server<\/a>\u00a0in the\u00a0Couchbase Mobile<\/a>\u00a0stack. \u00a0It’s a\u00a0secure web gateway that enables sync and data access over the web.<\/span><\/p>\n

That’s one way to look at it, which doesn’t really do Sync Gateway justice. \u00a0You can intelligently use it to link together clients without any back end, for example. \u00a0In a\u00a0previous post<\/a>, I talked about OpenID Connect support. \u00a0Sync Gateway acts there to ease the whole authorization flow. \u00a0There’s more, but in this post I want to focus on a new capability added in version 1.3.<\/p>\n

A Deeper Look at Syncing<\/h2>\n

Syncing (short for synchronizing) refers to keeping data consistent across two or more instances of a database. \u00a0Syncing can be a difficult problem. \u00a0Any time two writers try to make conflicting changes, the architecture has to deal with it.<\/p>\n

Some databases simply ignore the issue, forcing a single-writer only use. \u00a0Others depend on detecting conflicts in real time and rejecting them. \u00a0These approaches don’t work in cases where different copies of the database can’t always communicate to coordinate.<\/p>\n

A good\u00a0sync architecture\u00a0is a critical component of a full solution that addresses uses where a device may be on a slow network connection, or be disconnected entirely part of the time. \u00a0Sync Gateway implements a core piece of that architecture in Couchbase.<\/p>\n

We refer to the full stack as Couchbase Mobile. \u00a0Mobile uses are an obvious case where offline performance can be important. \u00a0Really, though, you can use Couchbase Mobile, including Sync Gateway, in many other scenarios. \u00a0Couchbase Lite and Sync Gateway run on a broad range of platforms, and are typically easy to port to new ones. \u00a0This makes Couchbase Mobile useful for anything from desktop (or maybe I should say laptop) to IoT.<\/p>\n

Here are some of the key feature to know about Sync Gateway replications in general:<\/p>\n