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How is logical replication different from physical replication in PostgreSQL?
Logical replicationin PostgreSQL allows users to perform a selective replication of a few tables and open a standby for writes. Whereas physical replicationin PostgreSQL is a block level replication. In this case, each database in the master is replicated to a standby, and the standby is not open for writes.
What’s the difference between logical replication and Wal based replication?
Logical Replication or Pglogical is a table level, WAL based replication mechanism which replicates the data of specific Tables between two PostgreSQL instances. There seems to be a confusion between “pglogical” and “Logical Replication”. Both of them provide the same kind of replication mechanism with some differences in features and capabilities.
Do you need a replica identity for PostgreSQL?
If you don’t want to publish all tables, you can specify the tables that you need to publish. You can also choose to limit the changes that will be published. However, for DELETE and UPDATE operations to be replicated, the “published” table should have a REPLICA IDENTITY, which can be a primary key.
Why do you need multiple copies of PostgreSQL?
When deploying applications in a production environment, it is always good for you to have multiple copies of the database. After making the copies, you must ensure that they are all in sync. This process of keeping database copies in sync is known as replication. There are two types of replication in PostgreSQL:
How are subscriptions used in PostgreSQL replication?
With your publication in place, you can now add a subscriber that will pull data from it. Subscriptions are used by PostgreSQL to connect to existing publications. A publication can have many subscriptions across different replica servers, and replica servers can also have their own publications with subscribers.
Which is the primary key of a PostgreSQL table?
The primary key of a table is its default replica identity. You can also make a unique index with NO NULL values as a replica identity. If there is no primary key or a unique index with NO NULLs, then you can set the replica_identity to FULL. When a replica identity is set to FULL, postgres uses the entire row as a key.
Why is PostgreSQL used for peer to peer replication?
It also allows for peer-to-peer replication between geographically distributed database servers. PostgreSQL is an open-source object-relational database system that is highly extensible and compliant with ACID (Atomicity, Consistency, Isolation, Durability) and the SQL standard.