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What is point in time recovery in PostgreSQL?
PostgreSQL “Point-in-time Recovery” (PITR) also called as incremental database backup, online backup or may be archive backup. The PostgreSQL server records all users’ data modification transaction like insert, update or delete and write it into a file call write-ahead (WAL) log file.
How is point in time recovery ( PITR ) useful?
Point-in-time recovery (PITR) is a pretty useful feature. You need to keep in mind that the backup is a “snapshot” of your dataset at a given point of time. If you take backups on a daily basis, in the worst case scenario, you will have almost 24 hours of data that is not in more than you had in your last backup.
What are the advantages of point in time recovery?
PostgreSQL Point-in-time Recovery (Incremental Backup) 1 Advantages. Zero down time – The incremental database backup is important to critical system that can not afford even a minute down time. 2 Database initialization. 3 Data Simulation & Backup Process. 4 Disaster come in. 5 Recovery Process. 6 Conclusion.
When do I need to restore to PostgreSQL database?
When you know at which point you need to restore to, you can proceed with the recovery. First, you should stop the PostgreSQL server: ? Then you need to remove all of the data directory, restore the base backup and then remove any existing WAL files. PostgreSQL will copy the data from our WAL archive directory.
Where is the write ahead log in PostgreSQL?
At all times, PostgreSQL maintains a write ahead log (WAL) in the pg_wal/ subdirectory of the cluster’s data directory. The log records every change made to the database’s data files.
What does the Wal file in PostgreSQL do?
The PostgreSQL server records all users’ data modification transaction like insert, update or delete and write it into a file call write-ahead (WAL) log file. This mechanism use the history records stored in WAL file to do roll-forward changes made since last database full backup.
Why do we have a log in PostgreSQL?
This log exists primarily for crash-safety purposes: if the system crashes, the database can be restored to consistency by “replaying” the log entries made since the last checkpoint.