pg_restore is a utility provided by PostgreSQL for restoring a PostgreSQL database from an archive created by pg_dump in the custom, directory, or tar formats. This tool is crucial for database administrators and developers who need to restore databases for backup, migration, or replication purposes. In a Linux environment, pg_restore is commonly used due to the widespread use of PostgreSQL on Linux servers.

Examples:

1. Basic Restore Command:

   To restore a PostgreSQL database from a custom-format dump file, you can use the following command:

   pg_restore -U username -d dbname /path/to/dumpfile

   Replace username with your PostgreSQL username, dbname with the name of the database you want to restore, and /path/to/dumpfile with the path to your dump file.

2. Restoring a Specific Schema:

   If you need to restore only a specific schema from the dump file, you can use the -n option:

   pg_restore -U username -d dbname -n schemaname /path/to/dumpfile

   Replace schemaname with the name of the schema you want to restore.

3. Restoring with Clean Option:

   The -c option drops the database objects before creating them, ensuring that the restored objects are in a clean state:

   pg_restore -U username -d dbname -c /path/to/dumpfile

4. Restoring with Jobs for Faster Performance:

   To speed up the restore process, especially for large databases, you can use the -j option to specify the number of jobs (parallel processes):

   pg_restore -U username -d dbname -j 4 /path/to/dumpfile

   This command uses 4 parallel jobs to perform the restore.

5. Listing Contents of a Dump File:

   Before restoring, you might want to see what is inside the dump file. You can list the contents using the -l option:

   pg_restore -l /path/to/dumpfile

6. Restoring Specific Tables:

   To restore specific tables from the dump file, use the -t option followed by the table names:

   pg_restore -U username -d dbname -t tablename1 -t tablename2 /path/to/dumpfile

7. Example Script for Automated Restore:

   Here is a sample bash script for automating the restore process:

   #!/bin/bash
   USER="your_username"
   DBNAME="your_dbname"
   DUMPFILE="/path/to/dumpfile"
   
   echo "Starting restore process..."
   pg_restore -U $USER -d $DBNAME -c $DUMPFILE
   echo "Restore process completed."