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How to set up streaming replication in PostgreSQL?
Postgres WAL replication or streaming replication can be set up quite easily upon installing the PostgreSQL on all servers. Here you need to configure both the master node & the standby node.
How to set up a Postgres Wal replication node?
The master server now allows a user named rep_user to connect & act as the slave server using the specified IP for replication. This is how master node can be set up for Postgres WAL replication. Once the master node is configured, the next step for Postgres WAL replication is to configure the standby node.
Which is the first step in replication in PostgreSQL?
Once the master node is configured, the next step for PostgreSQL replication is to configure the standby node. You can configure the standby node in two simple steps: Use the pg_basebackup utility to create a backup of the master node. This will be used as the starting point for the slave mode.
How does PostgreSQL master-replica failover work?
Depending on the role: Warm Standby (available only for promoting to master in-case of failure and does not have any active role) and Hot Standby (available for read only transactions). Failover Results: There is no advantage in this case for failover in either scenario.
Where can I find the Postgres Wal replication file?
The file is usually found in the data directory of PostgreSQL. The master server now allows a user named rep_user to connect & act as the slave server using the specified IP for replication. This is how master node can be set up for Postgres WAL replication.
How to stream Wal to the frontend in PostgreSQL?
Instructs server to start streaming WAL, starting at WAL position XXX / XXX. The server can reply with an error, e.g. if the requested section of WAL has already been recycled. On success, server responds with a CopyBothResponse message, and then starts to stream WAL to the frontend.
Which is the default setting for streaming replication?
wal_level = replica – With this parameter settings, the master server decides on how much information is written to the WAL. The default value of this parameter is replica. With this setting, the sender writes enough data to enable streaming replication.
I want to set up PostgreSQL streaming replication, but get the following error: FATAL: could not receive data from WAL stream: ERROR: requested WAL segment 00000001000000000000006A has already been removed. Master IP : 192.168.0.30
Is there a PostgreSQL error with Wal segment?
FATAL: could not receive data from WAL stream: ERROR: requested WAL segment 00000001000000000000006A has already been removed. Master IP : 192.168.0.30 Slave IP : 192.168.0.36 I have created a user rep which is used solely for replication. The relevant files inside Postgres config directory ( /opt/Postgres/9.3/data ):
Can a streaming replication server recycle WAL segments?
If you use streaming replication without file-based continuous archiving, the server might recycle old WAL segments before the standby has received them. If this occurs, the standby will need to be reinitialized from a new base backup.
What to do with Wal files for Postgres slave reset?
The solutions in What to do with WAL files for Postgres Slave reset are for a slightly different problem. They seem to be for a scenario where the master deletes a log file before the slave receives it. In my case it is very much present on the slave and several other files in the sequence after the one being requested.
Why does Postgres keep up with Wal creation rate?
Ensure that your WAL archival processes are not broken, and can keep up with the WAL creation rate. Replication failures: When using streaming replication with replication slots, and a standby goes down, Postgres will retain the WAL files needed by the standby so that the stanby can resume from the point where it left off.
What causes PostgreSQL to leave Wal files unmonitored?
On top of all this, features like WAL archiving and replication slots can cause the retention of WAL files. The biggest risk of leaving WAL files unmonitored is that PostgreSQL can, and will happily, retain them indefinitely if need be. They will grow unchecked and can end up consuming all available disk space.