PostgreSQL 12 High Availability Cookbook - Third Edition

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One difficulty associated with using the bdr.join_node_group function is that it relies on PostgreSQL logical replication semantics to transfer data from the remote node. The associated overhead makes this a fairly slow process, and for larger databases may mean days or even weeks of data synchronization. Assuming a single function call can survive for that long is a very risky proposition.

As a result, BDR also provides a command-line tool that can convert a physical replica into a BDR node. Using the same node DSNs and names as in the recipes, converting pgha2 would work like this:

bdr_init_physical -D /db/pgdata \     --node-name=tokyo \     --remote-dsn='dbname=myapp host=pgha1 user=bdr_user' \  --local-dsn='dbname=myapp host=pgha2 ...