EDB Postgres Distributed v3.6

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EDB Postgres Distributed provides loosely-coupled multi-master logical replication using a mesh topology. This means that you can write to any server and the changes are sent directly, row-by-row to all the other servers that are part of the same mesh.

EDB Postgres Distributed consists of several components that make the whole cluster work.

Postgres server

Two different Postgres distributions can be used:

What Postgres distribution and version is right for you depends on the features you need. See the feature matrix in Choosing a Postgres distribution for detailed comparison.

BDR

A Postgres server with the BDR extension installed is referred to as a BDR node. BDR nodes can be either data nodes or witness nodes.

Witness nodes don't participate in data replication and are only used as a tie-breaker for consensus.

Available as two editions, BDR Standard provides essential multi-master replication capabilities for delivering row level consistency to address high availability and/or geographically distributed workloads. BDR Enterprise adds advanced conflict-handling and data-loss protection capabilities.

BDR Enterprise

To provide very high availability, avoid data conflicts, and to cope with more advanced usage scenarios, the Enterprise edition provides the following extensive additional features:

  • Eager replication provides conflict free replication by synchronizing across cluster nodes before committing a transaction
  • Commit at most once consistency guards application transactions even in the presence of node failures
  • Conflict-free replicated data types (CRDTs) provide mathematically proven consistency in asynchronous multi-master update scenarios
  • Column level conflict resolution enables per column last-update wins resolution to merge updates
  • Transform triggers execute on incoming data for modifying or advanced programmatic filtering
  • Conflict triggers provide custom resolution techniques when a conflict is detected

BDR Enterprise requires EDB Postgres Extended v11 (formerly known as 2ndQuadrant Postgres) which is SQL and on-disk compatible with PostgreSQL.

BDR Standard

The Standard edition provides loosely-coupled multi-master logical replication using a mesh topology. This means that you can write to any node and the changes will be sent directly, row-by-row to all the other nodes that are part of the EDB Postgres Distributed cluster.

By default BDR uses asynchronous replication to provide row-level eventual consistency, applying changes on the peer nodes only after the local commit.

The following are included to support very high availability and geographically distributed workloads:

  • Rolling application and database upgrades to address the largest source of downtime
  • DDL replication supports changes to application schema, ideal for use in continuous release environments
  • Sequence handling provides applications different options for generating unique surrogate ids that a multi-node aware
  • Tools to assess applications, monitor operation, and verify data consistency

BDR Standard requires PostgreSQL v10 or v11.

pglogical 3.6

BDR depends on the pglogical 3 extension to provide the replication channel upon which BDR builds.