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What is a Slony replication node in PostgreSQL?
Node: A specific PostgreSQL database as Slony replication node, which operates as either a master or slave for a replication set. Replication Set: A group of tables and / or sequences to be replicated.
How can I interfacing with Slony in PostgreSQL?
Interfacing with Slony can be done by either writing custom slonik commands, or compiling slony with the –with-perltools flag, which provides the ‘altperl’ scripts that help generate these slonik scripts needed. A ‘Replication Cluster’ is a collection of databases that are part of replication.
How does slonik work on a replicated table?
When executed, slonik will connect to all nodes defined and create the Slony schema on each. When the Slony daemons are kicked off, they will then clear out all data in the replicated tables on the slave (if there is any), and copy over all data from the master to the slave (s).
Is there a third party replication system for PostgreSQL?
Slony-I (referred to as just ‘Slony’ from here on out) is a third-party replication system for PostgreSQL that dates back to before version 8.0, making it one of the older options for replication available. It operates as a trigger-based replication method that is a ‘master to multiple slaves’ solution.
How to set up a Slony replication cluster?
After installation, a Slony replication cluster is set up by issuing a few commands using the ‘slonik’ binary. ‘slonik’ is a command with a simple, yet unique syntax of its own to initialize and maintain a slony cluster. It is the main interface for issuing commands to the running Slony cluster that is in charge of replication.
How does Slon daemon work in PostgreSQL replication?
Outside processes, called the ‘slon daemons’, connect to the databases as any other client and fetch the changes from the master, then replay them on all slave nodes subscribed to the master. In a well performing replication setup, this asynchronous replication can be expected to be anywhere 1 to 20 seconds lagged behind the master.