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What is PG base backup?
pg_basebackup is used to take base backups of a running PostgreSQL database cluster. The backup is made over a regular PostgreSQL connection, and uses the replication protocol. The connection must be made with a superuser or a user having REPLICATION permissions (see Section 21.2), and pg_hba.
What is Pragma Journal_mode WAL?
The text for PRAGMA journal_mode=wal. says: The WAL journaling mode uses a write-ahead log instead of a rollback journal to implement transactions. The WAL journaling mode is persistent; after being set it stays in effect across multiple database connections and after closing and reopening the database.
Why does PG _ basebackup not switch to a new Wal file?
The backup history file is not created in the database cluster backed up. pg_basebackup cannot force the standby to switch to a new WAL file at the end of backup. When you are using -X none, if write activity on the primary is low, pg_basebackup may need to wait a long time for the last WAL file required for the backup to be switched and archived.
How does Wal archiving work in PostgreSQL database?
Second, WAL archiving provides the capability for Point-in-Time recovery. Since the WAL is a continuous log of all the changes that happen to the database, it is possible to stop replaying the WAL at an arbitrary point during recovery and restore the database to any point in history that is spanned by the available WAL files.
Can You restore a backup using PG _ basebackup?
There are various options that you can specify such as storing the backup in another location or compressing the backup. The above command is the core of what you need though. Restoring a backup that was taken with pg_basebackup.
How to clean up Wals in PostgreSQL backup policy?
In order to do a clean up of WALs, we need to keep in mind the WAL retention requirements and criteria, as losing essential WALs can be disastrous. Criteria 1: All WALs from the time of the oldest backup, which still falls in the backup retention policy and Point-in-time requirement, need to be preserved.