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Is there a logical replication feature in PostgreSQL 10?
PostgreSQL 10 came with the welcome addition of the logical replication feature. This provides a more flexible and easier means to replicate your tables than the regular streaming replication mechanism. However, it does have some limitations that may or may not prevent you from employing it for replication.
How does logical replication work in azure database?
PostgreSQL’s logical replication and logical decoding features are supported in Azure Database for PostgreSQL – Flexible Server, for Postgres version 11. Logical replication and logical decoding have several similarities. They both use logical replication slots to send out data. A slot represents a stream of changes.
How is logical replication different from physical replication?
We use the term logical in contrast to physical replication, which uses exact block addresses and byte-by-byte replication. PostgreSQL supports both mechanisms concurrently, see Chapter 26. Logical replication allows fine-grained control over both data replication and security.
Why are my logical replication slots not available?
Slots and HA failover – Logical replication slots on the primary server are not available on the standby server in your secondary AZ. This applies to you if your server uses the zone-redundant high availability option. In the event of a failover to the standby server, logical replication slots will not be available on the standby.
Is it possible to selectively replicate a part of a database?
One big “feature” of streaming replication is that it’s all or nothing. All changes to all objects from all databases on the primary have to be shipped to the standby, and the standby has to import every change. It is not possible to selectively replicate a part of your database.
Why does logical replication not replicate the values?
This is because logical replication does not replicate the values for sequences since the next value of the sequence is not stored in the table itself. If you think about it logically, you can’t modify the same “autoincrement” value from two places without bidirectional synchronization.
How are Wal files shipped from primary to standby?
The process of shipping the WAL files from the primary to standby is called log shipping, and can be done manually (scripts to rsync changes from primary’s $PGDATA/pg_wal directory to secondary’s) or through streaming replication .