pg_probackup
pg_probackup — manage backup and recovery of Postgres Pro database clusters
Synopsis
pg_probackup version
pg_probackup help [command]
pg_probackup init -B backup_dir --skip-if-exists
pg_probackup add-instance -B backup_dir -D data_dir --instance instance_name --skip-if-exists
pg_probackup del-instance -B backup_dir --instance instance_name
pg_probackup set-config -B backup_dir --instance instance_name [option...]
pg_probackup set-backup -B backup_dir --instance instance_name -i backup_id [option...]
pg_probackup show-config -B backup_dir --instance instance_name [option...]
pg_probackup show -B backup_dir [option...]
pg_probackup backup -B backup_dir --instance instance_name -b backup_mode [option...]
pg_probackup restore -B backup_dir --instance instance_name [option...]
pg_probackup checkdb -B backup_dir --instance instance_name -D data_dir [option...]
pg_probackup validate -B backup_dir [option...]
pg_probackup merge -B backup_dir --instance instance_name -i backup_id [option...]
pg_probackup delete -B backup_dir --instance instance_name { -i backup_id | --delete-wal | --delete-expired | --merge-expired } [option...]
pg_probackup archive-push -B backup_dir --instance instance_name --wal-file-path wal_file_path --wal-file-name wal_file_name [option...]
pg_probackup archive-get -B backup_dir --instance instance_name --wal-file-path wal_file_path --wal-file-name wal_file_name [option...]
pg_probackup catchup -b catchup_mode --source-pgdata=path_to_pgdata_on_remote_server --destination-pgdata=path_to_local_dir [option...]
Description
pg_probackup is a utility to manage backup and recovery of Postgres Pro database clusters. It is designed to perform periodic backups of the Postgres Pro instance that enable you to restore the server in case of a failure. pg_probackup supports PostgreSQL 11 or higher.
Overview
As compared to other backup solutions, pg_probackup offers the following benefits that can help you implement different backup strategies and deal with large amounts of data:
Incremental backup: with three different incremental modes, you can plan the backup strategy in accordance with your data flow. Incremental backups allow you to save disk space and speed up backup as compared to taking full backups. It is also faster to restore the cluster by applying incremental backups than by replaying WAL files.
Incremental restore: speed up restore from backup by reusing valid unchanged pages available in PGDATA.
Validation: automatic data consistency checks and on-demand backup validation without actual data recovery.
Verification: on-demand verification of Postgres Pro instance with the
checkdbcommand.Retention: managing WAL archive and backups in accordance with retention policy. You can configure retention policy based on recovery time or the number of backups to keep, as well as specify time to live (TTL) for a particular backup. Expired backups can be merged or deleted.
Parallelization: running
backup,restore,merge,delete,validate, andcheckdbprocesses on multiple parallel threads.Compression: storing backup data in a compressed state to save disk space.
Deduplication: saving disk space by excluding non-data files (such as
_vmor_fsm) from incremental backups if these files have not changed since they were copied into one of the previous backups in this incremental chain.Remote operations: backing up Postgres Pro instance located on a remote system or restoring a backup remotely.
Backup from standby: avoiding extra load on master by taking backups from a standby server.
External directories: backing up files and directories located outside of the Postgres Pro data directory (
PGDATA), such as scripts, configuration files, logs, or SQL dump files.Backup catalog: getting the list of backups and the corresponding meta information in plain text or JSON formats.
Archive catalog: getting the list of all WAL timelines and the corresponding meta information in plain text or JSON formats.
Partial restore: restoring only the specified databases.
Catchup: cloning a Postgres Pro instance for a fallen-behind standby server to “catch up” with master.
To manage backup data, pg_probackup creates a backup catalog. This is a directory that stores all backup files with additional meta information, as well as WAL archives required for point-in-time recovery. You can store backups for different instances in separate subdirectories of a single backup catalog.
Using pg_probackup, you can take full or incremental backups:
FULL backups contain all the data files required to restore the database cluster.
Incremental backups operate at the page level, only storing the data that has changed since the previous backup. It allows you to save disk space and speed up the backup process as compared to taking full backups. It is also faster to restore the cluster by applying incremental backups than by replaying WAL files. pg_probackup supports the following modes of incremental backups:
DELTA backup. In this mode, pg_probackup reads all data files in the data directory and copies only those pages that have changed since the previous backup. This mode can impose read-only I/O pressure equal to a full backup.
PAGE backup. In this mode, pg_probackup scans all WAL files in the archive from the moment the previous full or incremental backup was taken. Newly created backups contain only the pages that were mentioned in WAL records. This requires all the WAL files since the previous backup to be present in the WAL archive. If the size of these files is comparable to the total size of the database cluster files, speedup is smaller, but the backup still takes less space. You have to configure WAL archiving as explained in Setting up continuous WAL archiving to make PAGE backups.
PTRACK backup. In this mode, Postgres Pro tracks page changes on the fly. Continuous archiving is not necessary for it to operate. Each time a relation page is updated, this page is marked in a special PTRACK bitmap. Tracking implies some minor overhead on the database server operation, but speeds up incremental backups significantly.
pg_probackup can take only physical online backups, and online backups require WAL for consistent recovery. So regardless of the chosen backup mode (FULL, PAGE or DELTA), any backup taken with pg_probackup must use one of the following WAL delivery modes:
ARCHIVE. Such backups rely on continuous archiving to ensure consistent recovery. This is the default WAL delivery mode.
STREAM. Such backups include all the files required to restore the cluster to a consistent state at the time the backup was taken. Regardless of continuous archiving having been set up or not, the WAL segments required for consistent recovery are streamed via replication protocol during backup and included into the backup files. That's why such backups are called autonomous, or standalone.
Limitations
pg_probackup currently has the following limitations:
The remote mode is not supported on Windows systems.
On Unix systems, for Postgres Pro 11, a backup can be made only by the same OS user that has started the Postgres Pro server. For example, if Postgres Pro server is started by user
postgres, thebackupcommand must also be run by userpostgres. To satisfy this requirement when taking backups in the remote mode using SSH, you must set--remote-useroption topostgres.The Postgres Pro server from which the backup was taken and the restored server must be compatible by the block_size and wal_block_size parameters and have the same major release number. Depending on cluster configuration, Postgres Pro itself may apply additional restrictions, such as CPU architecture or libc/icu versions.
Quick Start
To quickly get started with pg_probackup, complete the steps below. This will set up FULL and DELTA backups in the remote mode and demonstrate some basic pg_probackup operations. In the following, these terms are used:
backup— Postgres Pro role used to connect to the Postgres Pro cluster.backupdb— database used to connect to the Postgres Pro cluster.backup_host— host with the backup catalog.backup_user— user onbackup_hostrunning all pg_probackup operations./mnt/backups— directory onbackup_hostwhere the backup catalog is stored.postgres_host— host with the Postgres Pro cluster.postgres— user onpostgres_hostunder which Postgres Pro cluster processes are running./var/lib/pgpro/std-16/data— Postgres Pro data directory onpostgres_host.
Steps to perform:
Install pg_probackup on both
backup_hostandpostgres_host.Set up an SSH connection from
backup_hosttopostgres_host.Configure your database cluster for STREAM backups.
Initialize the backup catalog:
[backup_user@backup_host]$ pg_probackup init -B /mnt/backups INFO: Backup catalog '/mnt/backups' successfully initialized
Add a backup instance called
mydbto the backup catalog:[backup_user@backup_host]$ pg_probackup add-instance \ -B /mnt/backups \ -D /var/lib/pgpro/std-16/data \ --instance=mydb \ --remote-host=postgres_host \ --remote-user=postgres INFO: Instance 'mydb' successfully initializedMake a FULL backup:
[backup_user@backup_host] pg_probackup backup \ -B /mnt/backups \ -b FULL \ --instance=mydb \ --stream \ --remote-host=postgres_host \ --remote-user=postgres \ -U backup \ -d backupdb INFO: Backup start, pg_probackup version: 2.7.0, instance: mydb, backup ID: S6674L, backup mode: FULL, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: This PostgreSQL instance was initialized with data block checksums. Data block corruption will be detected INFO: Database backup start INFO: wait for pg_backup_start() INFO: PGDATA size: 30MB INFO: Current Start LSN: 0/2000028, TLI: 1 INFO: Start transferring data files INFO: Data files are transferred, time elapsed: 0 INFO: wait for pg_stop_backup() INFO: pg_stop_backup() successfully executed INFO: stop_stream_lsn 0/3000000 currentpos 0/3000000 INFO: backup->stop_lsn 0/200F8B0 INFO: Getting the Recovery Time from WAL INFO: Syncing backup files to disk INFO: Backup files are synced, time elapsed: 1s INFO: Validating backup S6674L INFO: Backup S6674L data files are valid INFO: Backup S6674L resident size: 46MB INFO: Backup S6674L completedList the backups of the instance:
[backup_user@backup_host] pg_probackup show -B /mnt/backups --instance=mydb ============================================================================================================================================= Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status ============================================================================================================================================= mydb 16 S6674L 2023-12-24 12:09:57.799492+00 FULL STREAM 1/0 1s 30MB 16MB none 1.00 0/2000028 0/200F8B0 OK
Make an incremental backup in the DELTA mode:
[backup_user@backup_host] pg_probackup backup \ -B /mnt/backups \ -b delta \ --instance=mydb \ --stream \ --remote-host=postgres_host \ --remote-user=postgres \ -U backup \ -d backupdb INFO: Backup start, pg_probackup version: 2.7.0, instance: mydb, backup ID: S667BR, backup mode: DELTA, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: This PostgreSQL instance was initialized with data block checksums. Data block corruption will be detected INFO: Database backup start INFO: wait for pg_backup_start() INFO: Parent backup: S6674L INFO: PGDATA size: 30MB INFO: Current Start LSN: 0/4000028, TLI: 1 INFO: Parent Start LSN: 0/2000028, TLI: 1 INFO: Start transferring data files INFO: Data files are transferred, time elapsed: 1s INFO: wait for pg_stop_backup() INFO: pg_stop_backup() successfully executed INFO: stop_stream_lsn 0/5000000 currentpos 0/5000000 INFO: backup->stop_lsn 0/4000170 INFO: Getting the Recovery Time from WAL INFO: Syncing backup files to disk INFO: Backup files are synced, time elapsed: 0 INFO: Validating backup S667BR INFO: Backup S667BR data files are valid INFO: Backup S667BR resident size: 16MB INFO: Backup S667BR completedAdd or modify some parameters in the pg_probackup configuration file, so that you do not have to specify them each time on the command line:
[backup_user@backup_host] pg_probackup set-config \ -B /mnt/backups \ --instance=mydb \ --remote-host=postgres_host \ --remote-user=postgres \ -U backup \ -d backupdbCheck the configuration of the instance:
[backup_user@backup_host] pg_probackup show-config -B /mnt/backups --instance=mydb # Backup instance information pgdata = /var/lib/pgpro/std-16/data system-identifier = 7316129607401733083 xlog-seg-size = 16777216 # Connection parameters pgdatabase = backupdb pghost = postgres_host pguser = backup # Archive parameters archive-timeout = 5min # Logging parameters log-level-console = INFO log-level-file = OFF log-format-console = PLAIN log-format-file = PLAIN log-filename = pg_probackup.log log-rotation-size = 0TB log-rotation-age = 0d # Retention parameters retention-redundancy = 0 retention-window = 0 wal-depth = 0 # Compression parameters compress-algorithm = none compress-level = 1 # Remote access parameters remote-proto = ssh remote-host = postgres_host remote-user = postgres
Note that the parameters not modified via
set-configretain their default values.Make another incremental backup in the DELTA mode, omitting the parameters stored in the configuration file earlier:
[backup_user@backup_host] pg_probackup backup -B /mnt/backups --instance=mydb -b delta --stream INFO: Backup start, pg_probackup version: 2.7.0, instance: mydb, backup ID: S667F1, backup mode: DELTA, wal mode: STREAM, remote: true, compress-algorithm: none, compress-level: 1 INFO: This PostgreSQL instance was initialized with data block checksums. Data block corruption will be detected INFO: Database backup start INFO: wait for pg_backup_start() INFO: Parent backup: S667BR INFO: PGDATA size: 30MB INFO: Current Start LSN: 0/6000028, TLI: 1 INFO: Parent Start LSN: 0/4000028, TLI: 1 INFO: Start transferring data files INFO: Data files are transferred, time elapsed: 0 INFO: wait for pg_stop_backup() INFO: pg_stop_backup() successfully executed INFO: stop_stream_lsn 0/7000000 currentpos 0/7000000 INFO: backup->stop_lsn 0/6000170 INFO: Getting the Recovery Time from WAL INFO: Syncing backup files to disk INFO: Backup files are synced, time elapsed: 0 INFO: Validating backup S667F1 INFO: Backup S667F1 data files are valid INFO: Backup S667F1 resident size: 16MB INFO: Backup S667F1 completed
List the backups of the instance again:
[backup_user@backup_host] pg_probackup show -B /mnt/backups --instance=mydb =============================================================================================================================================== Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status =============================================================================================================================================== mydb 16 S667F1 2023-12-24 12:16:13.972949+00 DELTA STREAM 1/1 1s 119kB 16MB none 1.00 0/6000028 0/6000170 OK mydb 16 S667BR 2023-12-24 12:14:16.072569+00 DELTA STREAM 1/1 1s 183kB 16MB none 1.00 0/4000028 0/4000170 OK mydb 16 S6674L 2023-12-24 12:09:57.799492+00 FULL STREAM 1/0 1s 30MB 16MB none 1.00 0/2000028 0/200F8B0 OK
Restore the data from the latest available backup to an arbitrary location:
[backup_user@backup_host] pg_probackup restore -B /mnt/backups -D /var/lib/pgpro/std-16/staging-data --instance=mydb INFO: Validating parents for backup S667F1 INFO: Validating backup S6674L INFO: Backup S6674L data files are valid INFO: Validating backup S667BR INFO: Backup S667BR data files are valid INFO: Validating backup S667F1 INFO: Backup S667F1 data files are valid INFO: Backup S667F1 WAL segments are valid INFO: Backup S667F1 is valid. INFO: Restoring the database from backup at 2023-12-24 12:16:13+00 INFO: Start restoring backup files. PGDATA size: 46MB INFO: Backup files are restored. Transferred bytes: 46MB, time elapsed: 1s INFO: Restore incremental ratio (less is better): 100% (46MB/46MB) INFO: Syncing restored files to disk INFO: Restored backup files are synced, time elapsed: 0 INFO: Restore of backup S667F1 completed.
Installation and Setup
Once you have pg_probackup installed, complete the following setup:
Initialize the backup catalog.
Add a new backup instance to the backup catalog.
Configure the database cluster to enable pg_probackup backups.
Optionally, configure SSH for running pg_probackup operations in the remote mode.
Initializing the Backup Catalog
pg_probackup stores all WAL and backup files in the corresponding subdirectories of the backup catalog.
To initialize the backup catalog, run the following command:
pg_probackup init -B backup_dir
where backup_dir is the path to the backup catalog. If the backup_dir already exists, it must be empty. Otherwise, pg_probackup returns an error.
The user launching pg_probackup must have full access to the backup_dir directory.
pg_probackup creates the backup_dir backup catalog, with the following subdirectories:
wal/— directory for WAL files.backups/— directory for backup files.
Once the backup catalog is initialized, you can add a new backup instance.
Adding a New Backup Instance
pg_probackup can store backups for multiple database clusters in a single backup catalog. To set up the required subdirectories, you must add a backup instance to the backup catalog for each database cluster you are going to back up.
To add a new backup instance, run the following command:
pg_probackup add-instance -Bbackup_dir-Ddata_dir--instanceinstance_name[remote_options]
Where:
data_diris the data directory of the cluster you are going to back up. To set up and use pg_probackup, write access to this directory is required.instance_nameis the name of the subdirectories that will store WAL and backup files for this cluster.remote_options are optional parameters that need to be specified only if
data_diris located on a remote system.
pg_probackup creates the instance_name subdirectories under the backups/ and wal/ directories of the backup catalog. The backups/ directory contains the instance_namepg_probackup.conf configuration file that controls pg_probackup settings for this backup instance. If you run this command with the remote_options, the specified parameters will be added to pg_probackup.conf.
For details on how to fine-tune pg_probackup configuration, see the section called “Configuring pg_probackup”.
The user launching pg_probackup must have full access to backup_dir directory and at least read-only access to data_dir directory. If you specify the path to the backup catalog in the BACKUP_PATH environment variable, you can omit the corresponding option when running pg_probackup commands.
Note
For Postgres Pro 11 or higher, it is recommended to use the group access feature, so that backup can be done by any OS user in the same group as the cluster owner. In this case, the user should have read permissions for the cluster directory.
Configuring the Database Cluster
Although pg_probackup can be used by a superuser, it is recommended to create a separate role with the minimum permissions required for the chosen backup strategy. In these configuration instructions, the backup role is used as an example.
For security reasons, it is recommended to run the configuration SQL queries below in a separate database.
postgres=# CREATE DATABASE backupdb; postgres=# \c backupdb
To perform a backup, the following permissions for role backup are required only in the database used for connection to the Postgres Pro server.
For Postgres Pro versions 11 — 14:
BEGIN; CREATE ROLE backup WITH LOGIN; GRANT USAGE ON SCHEMA pg_catalog TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.current_setting(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.set_config(text, text, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_is_in_recovery() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_start_backup(text, boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_stop_backup(boolean, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_create_restore_point(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_switch_wal() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_last_wal_replay_lsn() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current_snapshot() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_snapshot_xmax(txid_snapshot) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_control_checkpoint() TO backup; COMMIT;
For Postgres Pro 15 or higher:
BEGIN; CREATE ROLE backup WITH LOGIN; GRANT USAGE ON SCHEMA pg_catalog TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.current_setting(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.set_config(text, text, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_is_in_recovery() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_backup_start(text, boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_backup_stop(boolean) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_create_restore_point(text) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_switch_wal() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_last_wal_replay_lsn() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_current_snapshot() TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.txid_snapshot_xmax(txid_snapshot) TO backup; GRANT EXECUTE ON FUNCTION pg_catalog.pg_control_checkpoint() TO backup; COMMIT;
In the pg_hba.conf file, allow connection to the database cluster on behalf of the backup role.
Since pg_probackup needs to read cluster files directly, pg_probackup must be started by (or connected to, if used in the remote mode) the OS user that has read access to all files and directories inside the data directory (PGDATA) you are going to back up.
Depending on whether you plan to take standalone or archive backups, Postgres Pro cluster configuration will differ, as specified in the sections below. To back up the database cluster from a standby server, run pg_probackup in the remote mode, or create PTRACK backups, additional setup is required.
For details, see the sections Setting up STREAM Backups, Setting up continuous WAL archiving, Setting up Backup from Standby, Configuring the Remote Mode, Setting up Partial Restore, and Setting up PTRACK Backups.
Setting up STREAM Backups
To set up the cluster for STREAM backups, complete the following steps:
If the
backuprole does not exist, create it with theREPLICATIONprivilege when Configuring the Database Cluster:CREATE ROLE backup WITH LOGIN REPLICATION;
If the
backuprole already exists, grant it with theREPLICATIONprivilege:ALTER ROLE backup WITH REPLICATION;
In the pg_hba.conf file, allow replication on behalf of the
backuprole.Make sure the parameter max_wal_senders is set high enough to leave at least one session available for the backup process.
Set the parameter wal_level to be higher than
minimal.
If you are planning to take PAGE backups in the STREAM mode or perform PITR with STREAM backups, you still have to configure WAL archiving, as explained in the section Setting up continuous WAL archiving.
Once these steps are complete, you can start taking FULL, PAGE, DELTA, and PTRACK backups in the STREAM WAL mode.
Note
If you are planning to rely on .pgpass for authentication when running backup in STREAM mode, then .pgpass must contain credentials for replication database, used to establish connection via replication protocol. Example: pghost:5432:replication:backup_user:my_strong_password
Setting up Continuous WAL Archiving
Making backups in PAGE backup mode, performing PITR and making backups with ARCHIVE WAL delivery mode require continuous WAL archiving to be enabled. To set up continuous archiving in the cluster, complete the following steps:
Make sure the wal_level parameter is higher than
minimal.If you are configuring archiving on master, archive_mode must be set to
onoralways. To perform archiving on standby, set this parameter toalways.Set the archive_command parameter, as follows:
archive_command = '"
install_dir/pg_probackup" archive-push -B "backup_dir" --instanceinstance_name--wal-file-name=%f [remote_options]'
where install_dir is the installation directory of the pg_probackup version you are going to use, backup_dir and instance_name refer to the already initialized backup catalog instance for this database cluster, and remote_options only need to be specified to archive WAL on a remote host. For details about all possible archive-push parameters, see the section archive-push.
Once these steps are complete, you can start making backups in the ARCHIVE WAL mode, backups in the PAGE backup mode, as well as perform PITR.
You can view the current state of the WAL archive using the show command. For details, see the section called “Viewing WAL Archive Information”.
If you are planning to make PAGE backups and/or backups with ARCHIVE WAL mode from a standby server that generates a small amount of WAL traffic, without long waiting for WAL segment to fill up, consider setting the archive_timeout Postgres Pro parameter on master. The value of this parameter should be slightly lower than the --archive-timeout setting (5 minutes by default), so that there is enough time for the rotated segment to be streamed to standby and sent to WAL archive before the backup is aborted because of --archive-timeout.
Note
Instead of using the archive-push command provided by pg_probackup, you can use any other tool to set up continuous archiving as long as it delivers WAL segments into backup_dir/wal/instance_namegzip, and .gz suffix in filename is mandatory.
Note
Instead of configuring continuous archiving by setting the archive_mode and archive_command parameters, you can opt for using the pg_receivewal utility. In this case, pg_receivewal -D option should point to directorybackup_dir/wal/instance_name
Setting up Backup from Standby
pg_probackup can take backups from a standby server. This requires the following additional setup:
On the standby server, set the hot_standby parameter to
on.On the master server, set the full_page_writes parameter to
on.To perform standalone backups on standby, complete all steps in section Setting up STREAM Backups.
To perform archive backups on standby, complete all steps in section Setting up continuous WAL archiving.
Once these steps are complete, you can start taking FULL, PAGE, DELTA, or PTRACK backups with appropriate WAL delivery mode: ARCHIVE or STREAM, from the standby server.
Backup from the standby server has the following limitations:
If the standby is promoted to the master during backup, the backup fails.
All WAL records required for the backup must contain sufficient full-page writes. This requires you to enable
full_page_writeson the master, and not to use tools like pg_compresslog as archive_command to remove full-page writes from WAL files.
Setting up Cluster Verification
Logical verification of a database cluster requires the following additional setup. Role backup is used as an example:
Install the amcheck or amcheck_next extension in every database of the cluster:
CREATE EXTENSION amcheck;
Grant the following permissions to the
backuprole in every database of the cluster:
GRANT SELECT ON TABLE pg_catalog.pg_am TO backup; GRANT SELECT ON TABLE pg_catalog.pg_class TO backup; GRANT SELECT ON TABLE pg_catalog.pg_database TO backup; GRANT SELECT ON TABLE pg_catalog.pg_namespace TO backup; GRANT SELECT ON TABLE pg_catalog.pg_extension TO backup; GRANT EXECUTE ON FUNCTION bt_index_check(regclass) TO backup; GRANT EXECUTE ON FUNCTION bt_index_check(regclass, bool) TO backup; GRANT EXECUTE ON FUNCTION bt_index_check(regclass, bool, bool) TO backup;
Setting up Partial Restore
If you are planning to use partial restore, complete the following additional step:
Grant the read-only access to
pg_catalog.pg_databaseto thebackuprole only in the database used for connection to Postgres Pro server:GRANT SELECT ON TABLE pg_catalog.pg_database TO backup;
Configuring the Remote Mode
pg_probackup supports the remote mode that allows you to perform backup, restore and WAL archiving operations remotely. In this mode, the backup catalog is stored on a local system, while Postgres Pro instance to backup and/or to restore is located on a remote system. Currently the only supported remote protocol is SSH.
Set up SSH
If you are going to use pg_probackup in remote mode via SSH, complete the following steps:
Install pg_probackup on both systems:
backup_hostandpostgres_host.For communication between the hosts set up a passwordless SSH connection between the
backup_useruser onbackup_hostand thepostgresuser onpostgres_host:[backup_user@backup_host] ssh-copy-id postgres@postgres_host
Where:
backup_hostis the system with backup catalog.postgres_hostis the system with the Postgres Pro cluster.backup_useris the OS user onbackup_hostused to run pg_probackup.postgresis the user onpostgres_hostunder which Postgres Pro cluster processes are running. For Postgres Pro 11 or higher a more secure approach can be used thanks to group access feature.
If you are going to rely on continuous WAL archiving, set up a passwordless SSH connection between the
postgresuser onpostgres_hostand thebackupuser onbackup_host:[postgres@postgres_host] ssh-copy-id backup_user@backup_host
Make sure pg_probackup on
postgres_hostcan be located when a connection via SSH is made. For example, for Bash, you can modifyPATHin~/.bashrcof thepostgresuser (above the line inbashrcthat exits the script for non-interactive shells). Alternatively, for pg_probackup commands, specify the path to the directory containing the pg_probackup binary onpostgres_hostvia the --remote-path option.
pg_probackup in the remote mode via SSH works as follows:
Only the following commands can be launched in the remote mode: add-instance, backup, restore, catchup, archive-push, and archive-get.
Operating in remote mode requires pg_probackup binary to be installed on both local and remote systems. The versions of local and remote binary must be the same.
When started in the remote mode, the main pg_probackup process on the local system connects to the remote system via SSH and launches one or more agent processes on the remote system, which are called remote agents. The number of remote agents is equal to the
-j/--threadssetting.The main pg_probackup process uses remote agents to access remote files and transfer data between local and remote systems.
Remote agents try to minimize the network traffic and the number of round-trips between hosts.
The main process is usually started on
backup_hostand connects topostgres_host, but in case ofarchive-pushandarchive-getcommands the main process is started onpostgres_hostand connects tobackup_host.Once data transfer is complete, remote agents are terminated and SSH connections are closed.
If an error condition is encountered by a remote agent, then all agents are terminated and error details are reported by the main pg_probackup process, which exits with an error.
Compression is always done on
postgres_host, while decompression is always done onbackup_host.
Note
You can impose additional restrictions on SSH settings to protect the system in the event of account compromise.
Note
Setting the number of threads (-j/--threads option) to a value greater than 10 for pg_probackup working in the remote mode via SSH may result in the actual number of SSH connections exceeding the maximum allowed number of simultaneous SSH connections on the remote server and consequently lead to an “ERROR: Agent error: kex_exchange_identification: Connection closed by remote host” error. To correct the error, either reduce the number of pg_probackup threads or adjust the value of MaxStartups configuration parameter of the remote SSH server. If SSH is set up as a xinetd service on the remote server, adjust the value of the xinetd per_source configuration parameter rather than MaxStartups.
Setting up PTRACK Backups
Note
PTRACK versions lower than 2.0 are deprecated and not supported. Postgres Pro Standard and Postgres Pro Enterprise versions starting with 11.9.1 contain PTRACK 2.0. Upgrade your server to avoid issues in backups that you will take in future and be sure to take fresh backups of your clusters with the upgraded PTRACK since the backups taken with PTRACK 1.x might be corrupt.
If you are going to use PTRACK backups, complete the following additional steps. The role that will perform PTRACK backups (the backup role in the examples below) must have access to all the databases of the cluster.
For Postgres Pro 11 or higher:
Create PTRACK extension:
CREATE EXTENSION ptrack;
To enable tracking page updates, set
ptrack.map_sizeparameter to a positive integer and restart the server.For optimal performance, it is recommended to set
ptrack.map_sizetoN/ 1024Nis the size of the Postgres Pro cluster, in MB. If you set this parameter to a lower value, PTRACK is more likely to map several blocks together, which leads to false-positive results when tracking changed blocks and increases the incremental backup size as unchanged blocks can also be copied into the incremental backup. Settingptrack.map_sizeto a higher value does not affect PTRACK operation, but it is not recommended to set this parameter to a value higher than 1024.
Note
If you change the ptrack.map_size parameter value, the previously created PTRACK map file is cleared, and tracking newly changed blocks starts from scratch. Thus, you have to retake a full backup before taking incremental PTRACK backups after changing ptrack.map_size.
Usage
Creating a Backup
To create a backup, run the following command:
pg_probackup backup -Bbackup_dir--instanceinstance_name-bbackup_mode
Where backup_mode can take one of the following values: FULL, DELTA, PAGE, and PTRACK.
When restoring a cluster from an incremental backup, pg_probackup relies on the parent full backup and all the incremental backups between them, which is called “the backup chain”. Thus, to perform incremental backups, it is necessary to have the last parent full backup with the status OK or DONE in the directory. If the parent full backup has the MERGING or MERGED status, an incremental backup cannot be performed.
For example, if merge has already been launched with a single full backup, an attempt to perform an incremental backup will end with the following messages:
WARNING: Valid full backup on current timeline 1 is not found, trying to look up on previous timelines WARNING: Cannot find valid backup on previous timelines ERROR: Create new full backup before an incremental one
ARCHIVE Mode
ARCHIVE is the default WAL delivery mode.
For example, to make a FULL backup in ARCHIVE mode, run:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL
ARCHIVE backups rely on continuous archiving to get WAL segments required to restore the cluster to a consistent state at the time the backup was taken.
When a backup is taken, pg_probackup ensures that WAL files containing WAL records between Start LSN and Stop LSN actually exist in backup_dir/wal/instance_nameStart LSN and Stop LSN can be parsed. This precaution eliminates the risk of silent WAL corruption.
STREAM Mode
STREAM is the optional WAL delivery mode.
For example, to make a FULL backup in the STREAM mode, add the --stream flag to the command from the previous example:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --stream --temp-slot
The optional --temp-slot flag ensures that the required segments remain available if the WAL is rotated before the backup is complete.
Unlike backups in ARCHIVE mode, STREAM backups include all the WAL segments required to restore the cluster to a consistent state at the time the backup was taken.
During backup pg_probackup streams WAL files containing WAL records between Start LSN and Stop LSN to backup_dir/backups/instance_name/backup_id/database/pg_walStart LSN and Stop LSN can be parsed.
Even if you are using continuous archiving, STREAM backups can still be useful in the following cases:
STREAM backups can be restored on the server that has no file access to WAL archive.
STREAM backups enable you to restore the cluster state at the point in time for which WAL files in archive are no longer available.
Backup in STREAM mode can be taken from a standby of a server that generates small amount of WAL traffic, without long waiting for WAL segment to fill up.
Page Validation
If data_checksums are enabled in the database cluster, pg_probackup uses this information to check correctness of data files during backup. While reading each page, pg_probackup checks whether the calculated checksum coincides with the checksum stored in the page header. This guarantees that the Postgres Pro instance and the backup itself have no corrupt pages. Note that pg_probackup reads database files directly from the filesystem, so under heavy write load during backup it can show false-positive checksum mismatches because of partial writes. If a page checksum mismatch occurs, the page is re-read and checksum comparison is repeated.
A page is considered corrupt if checksum comparison has failed more than 300 times. In this case, the backup is aborted.
Even if data checksums are not enabled, pg_probackup always performs sanity checks for page headers.
External Directories
To back up a directory located outside of the data directory, use the optional --external-dirs parameter that specifies the path to this directory. If you would like to add more than one external directory, you can provide several paths separated by colons on Linux systems or semicolons on Windows systems.
For example, to include /etc/dir1 and /etc/dir2 directories into the full backup of your instance_name instance that will be stored under the backup_dir directory on Linux, run:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --external-dirs=/etc/dir1:/etc/dir2
Similarly, to include C:\dir1 and C:\dir2 directories into the full backup on Windows, run:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --external-dirs=C:\dir1;C:\dir2
pg_probackup recursively copies the contents of each external directory into a separate subdirectory in the backup catalog. Since external directories included into different backups do not have to be the same, when you are restoring the cluster from an incremental backup, only those directories that belong to this particular backup will be restored. Any external directories stored in the previous backups will be ignored.
To include the same directories into each backup of your instance, you can specify them in the pg_probackup.conf configuration file using the set-config command with the --external-dirs option.
Performing Cluster Verification
To verify that Postgres Pro database cluster is not corrupt, run the following command:
pg_probackup checkdb [-Bbackup_dir[--instanceinstance_name]] [-Ddata_dir] [connection_options]
This command performs physical verification of all data files located in the specified data directory by running page header sanity checks, as well as block-level checksum verification if checksums are enabled. If a corrupt page is detected, checkdb continues cluster verification until all pages in the cluster are validated.
By default, similar page validation is performed automatically while a backup is taken by pg_probackup. The checkdb command enables you to perform such page validation on demand, without taking any backup copies, even if the cluster is not backed up using pg_probackup at all.
To perform cluster verification, pg_probackup needs to connect to the cluster to be verified. In general, it is enough to specify the backup instance of this cluster for pg_probackup to determine the required connection options. However, if -B and --instance options are omitted, you have to provide connection options and data_dir via environment variables or command-line options.
Physical verification cannot detect logical inconsistencies, missing or nullified blocks and entire files, or similar anomalies. Extensions amcheck and amcheck_next provide a partial solution to these problems.
If you would like, in addition to physical verification, to verify all indexes in all databases using these extensions, you can specify the --amcheck flag when running the checkdb command:
pg_probackup checkdb -Ddata_dir--amcheck [connection_options]
You can skip physical verification by specifying the --skip-block-validation flag. In this case, you can omit backup_dir and data_dir options, only connection options are mandatory:
pg_probackup checkdb --amcheck --skip-block-validation [connection_options]
Logical verification can be done more thoroughly with the --heapallindexed flag by checking that all heap tuples that should be indexed are actually indexed, but at the higher cost of CPU, memory, and I/O consumption.
Validating a Backup
pg_probackup calculates checksums for each file in a backup during the backup process. The process of checking checksums of backup data files is called the backup validation. By default, validation is run immediately after the backup is taken and right before the restore, to detect possible backup corruption.
If you would like to skip backup validation, you can specify the --no-validate flag when running backup and restore commands.
To ensure that all the required backup files are present and can be used to restore the database cluster, you can run the validate command with the exact recovery target options you are going to use for recovery.
For example, to check that you can restore the database cluster from a backup copy up to transaction ID 4242, run this command:
pg_probackup validate -Bbackup_dir--instanceinstance_name--recovery-target-xid=4242
If validation completes successfully, pg_probackup displays the corresponding message. If validation fails, you will receive an error message with the exact time, transaction ID, and LSN up to which the recovery is possible.
If you specify backup_id via -i/--backup-id option, then only the backup copy with specified backup ID will be validated. If backup_id is specified with recovery target options, the validate command will check whether it is possible to restore the specified backup to the specified recovery target.
For example, to check that you can restore the database cluster from a backup copy with the PT8XFX backup ID up to the specified timestamp, run this command:
pg_probackup validate -Bbackup_dir--instanceinstance_name-i PT8XFX --recovery-target-time="2017-05-18 14:18:11+03"
If you specify the backup_id of an incremental backup, all its parents starting from FULL backup will be validated.
If you omit all the parameters, all backups are validated.
Restoring a Cluster
To restore the database cluster from a backup, run the restore command with at least the following options:
pg_probackup restore -Bbackup_dir--instanceinstance_name-ibackup_id
Where:
backup_diris the backup catalog that stores all backup files and meta information.instance_nameis the backup instance for the cluster to be restored.backup_idspecifies the backup to restore the cluster from. If you omit this option, pg_probackup uses the latest valid backup available for the specified instance. If you specify an incremental backup to restore, pg_probackup automatically restores the underlying full backup and then sequentially applies all the necessary increments.
Once the restore command is complete, start the database service.
If you restore ARCHIVE backups, perform PITR, or specify the --restore-as-replica flag with the restore command to set up a standby server, pg_probackup creates a recovery configuration file once all data files are copied into the target directory. This file includes the minimal settings required for recovery, except for the password in the primary_conninfo parameter; you have to add the password manually or use the --primary-conninfo option, if required. For Postgres Pro 11, recovery settings are written into the recovery.conf file. Starting from Postgres Pro 12, pg_probackup writes these settings into the probackup_recovery.conf file and then includes it into postgresql.auto.conf.
If you are restoring a STREAM backup, the restore is complete at once, with the cluster returned to a self-consistent state at the point when the backup was taken. For ARCHIVE backups, Postgres Pro replays all available archived WAL segments, so the cluster is restored to the latest state possible within the current timeline. You can change this behavior by using the recovery target options with the restore command, as explained in the section called “Performing Point-in-Time (PITR) Recovery”.
If the cluster to restore contains tablespaces, pg_probackup restores them to their original location by default. To restore tablespaces to a different location, use the --tablespace-mapping/-T option. Otherwise, restoring the cluster on the same host will fail if tablespaces are in use, because the backup would have to be written to the same directories.
When using the --tablespace-mapping/-T option, you must provide absolute paths to the old and new tablespace directories. If a path happens to contain an equals sign (=), escape it with a backslash. This option can be specified multiple times for multiple tablespaces. For example:
pg_probackup restore -Bbackup_dir--instanceinstance_name-Ddata_dir-j 4 -ibackup_id-T tablespace1_dir=tablespace1_newdir-T tablespace2_dir=tablespace2_newdir
To restore the cluster on a remote host, follow the instructions in the section called “Using pg_probackup in the Remote Mode”.
Note
By default, the restore command validates the specified backup before restoring the cluster. If you run regular backup validations and would like to save time when restoring the cluster, you can specify the --no-validate flag to skip validation and speed up the recovery.
Incremental Restore
The speed of restore from backup can be significantly improved by replacing only invalid and changed pages in already existing Postgres Pro data directory using incremental restore options with the restore command.
To restore the database cluster from a backup in incremental mode, run the restore command with the following options:
pg_probackup restore -Bbackup_dir--instanceinstance_name-Ddata_dir-Iincremental_mode
Where incremental_mode can take one of the following values:
CHECKSUM — read all data files in the data directory, validate header and checksum in every page and replace only invalid pages and those with checksum and LSN not matching with corresponding page in backup. This is the simplest, the most fool-proof incremental mode. Recommended to use by default.
LSN — read the
pg_controlin the data directory to obtain redo LSN and redo TLI, which allows you to determine a point in history(shiftpoint), where data directory state shifted from target backup chain history. If shiftpoint is not within reach of backup chain history, then restore is aborted. If shiftpoint is within reach of backup chain history, then read all data files in the data directory, validate header and checksum in every page and replace only invalid pages and those with LSN greater than shiftpoint. This mode offers a greater speed up compared to CHECKSUM, but rely on two conditions to be met. First, data_checksums parameter must be enabled in data directory (to avoid corruption due to hint bits). This condition will be checked at the start of incremental restore and the operation will be aborted if checksums are disabled. Second, thepg_controlfile must be synched with state of data directory. This condition cannot checked at the start of restore, so it is a user responsibility to ensure thatpg_controlcontain valid information. Therefore it is not recommended to use LSN mode in any situation, where pg_control cannot be trusted or has been tampered with: afterpg_resetxlogexecution, after restore from backup without recovery been run, etc.NONE — regular restore without any incremental optimizations.
Regardless of chosen incremental mode, pg_probackup will check, that postmaster in given destination directory is not running and system-identifier is the same as in the backup.
Suppose you want to return an old master as replica after switchover using incremental restore in LSN mode:
==================================================================================================================================================
Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status
==================================================================================================================================================
node 12 QBRNBP 2020-06-11 17:40:58+03 DELTA ARCHIVE 16/15 40s 194MB 16MB zlib 8.26 15/2C000028 15/2D000128 OK
node 12 QBRIDX 2020-06-11 15:51:42+03 PAGE ARCHIVE 15/15 11s 18MB 16MB lz4 5.10 14/DC000028 14/DD0000B8 OK
node 12 QBRIAJ 2020-06-11 15:51:08+03 PAGE ARCHIVE 15/15 20s 141MB 96MB pglz 6.22 14/D4BABFE0 14/DA9871D0 OK
node 12 QBRHT8 2020-06-11 15:45:56+03 FULL ARCHIVE 15/0 2m:11s 1371MB 416MB zstd 10.93 14/9D000028 14/B782E9A0 OK
pg_probackup restore -B /backup --instance node -R -I lsn
INFO: Running incremental restore into nonempty directory: "/var/lib/pgsql/12/data"
INFO: Destination directory redo point 15/2E000028 on tli 16 is within reach of backup QBRIDX with Stop LSN 14/DD0000B8 on tli 15
INFO: shift LSN: 14/DD0000B8
INFO: Restoring the database from backup at 2020-06-11 17:40:58+03
INFO: Extracting the content of destination directory for incremental restore
INFO: Destination directory content extracted, time elapsed: 1s
INFO: Removing redundant files in destination directory
INFO: Redundant files are removed, time elapsed: 1s
INFO: Start restoring backup files. PGDATA size: 15GB
INFO: Backup files are restored. Transferred bytes: 1693MB, time elapsed: 43s
INFO: Restore incremental ratio (less is better): 11% (1693MB/15GB)
INFO: Restore of backup QBRNBP completed.
Note
Incremental restore is possible only for backups with program_version equal or greater than 2.4.0.
Partial Restore
If you have enabled partial restore before taking backups, you can restore only some of the databases using partial restore options with the restore commands.
To restore the specified databases only, run the restore command with the following options:
pg_probackup restore -Bbackup_dir--instanceinstance_name--db-include=database_name
The --db-include option can be specified multiple times. For example, to restore only databases db1 and db2, run the following command:
pg_probackup restore -Bbackup_dir--instanceinstance_name--db-include=db1 --db-include=db2
To exclude one or more databases from restore, use the --db-exclude option:
pg_probackup restore -Bbackup_dir--instanceinstance_name--db-exclude=database_name
The --db-exclude option can be specified multiple times. For example, to exclude the databases db1 and db2 from restore, run the following command:
pg_probackup restore -Bbackup_dir--instanceinstance_name--db-exclude=db1 --db-exclude=db2
Partial restore relies on lax behavior of Postgres Pro recovery process toward truncated files. For recovery to work properly, files of excluded databases are restored as files of zero size. After the Postgres Pro cluster is successfully started, you must drop the excluded databases using DROP DATABASE command.
To decouple a single cluster containing multiple databases into separate clusters with minimal downtime, you can do partial restore of the cluster as a standby using the --restore-as-replica option for specific databases.
Note
The template0 and template1 databases are always restored.
Note
Due to recovery specifics of Postgres Pro versions earlier than 12, it is advisable that you set the hot_standby parameter to off when running partial restore of a Postgres Pro cluster of version earlier than 12. Otherwise the recovery may fail.
Performing Point-in-Time (PITR) Recovery
If you have enabled continuous WAL archiving before taking backups, you can restore the cluster to its state at an arbitrary point in time (recovery target) using recovery target options with the restore command.
You can use both STREAM and ARCHIVE backups for point in time recovery as long as the WAL archive is available at least starting from the time the backup was taken. If -i/--backup-id option is omitted, pg_probackup automatically chooses the backup that is the closest to the specified recovery target and starts the restore process, otherwise pg_probackup will try to restore the specified backup to the specified recovery target.
To restore the cluster state at the exact time, specify the
--recovery-target-timeoption, in the timestamp format. For example:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target-time="2017-05-18 14:18:11+03"To restore the cluster state up to a specific transaction ID, use the
--recovery-target-xidoption:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target-xid=687To restore the cluster state up to the specific LSN, use
--recovery-target-lsnoption:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target-lsn=16/B374D848To restore the cluster state up to the specific named restore point, use
--recovery-target-nameoption:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target-name="before_app_upgrade"To restore the backup to the latest state available in the WAL archive, use
--recovery-targetoption withlatestvalue:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target="latest"To restore the cluster to the earliest point of consistency, use
--recovery-targetoption with theimmediatevalue:pg_probackup restore -B
backup_dir--instanceinstance_name--recovery-target='immediate'
Using pg_probackup in the Remote Mode
pg_probackup supports the remote mode that allows you to perform backup and restore operations remotely via SSH. In this mode, the backup catalog is stored on a local system, while Postgres Pro instance to be backed up is located on a remote system. You must have pg_probackup installed on both systems.
Note
pg_probackup relies on passwordless SSH connection for communication between the hosts.
Note
In addition to SSH connection, pg_probackup uses a regular connection to the database to manage the remote operation. See the section Configuring the Database Cluster for details of how to set up a database connection.
The typical workflow is as follows:
On your backup host, configure pg_probackup as explained in the section Installation and Setup. For the add-instance and set-config commands, make sure to specify remote options that point to the database host with the Postgres Pro instance.
If you would like to take remote backups in PAGE mode, or rely on ARCHIVE WAL delivery mode, or use PITR, configure continuous WAL archiving from the database host to the backup host as explained in the section Setting up continuous WAL archiving. For the archive-push and archive-get commands, you must specify the remote options that point to the backup host with the backup catalog.
Run backup or restore commands with remote options on the backup host. pg_probackup connects to the remote system via SSH and creates a backup locally or restores the previously taken backup on the remote system, respectively.
For example, to create an archive full backup of a Postgres Pro cluster located on a remote system with host address 192.168.0.2 on behalf of the postgres user via SSH connection through port 2302, run:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --remote-user=postgres --remote-host=192.168.0.2 --remote-port=2302
To restore the latest available backup on a remote system with host address 192.168.0.2 on behalf of the postgres user via SSH connection through port 2302, run:
pg_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=postgres --remote-host=192.168.0.2 --remote-port=2302
Restoring an ARCHIVE backup or performing PITR in the remote mode require additional information: destination address, port and username for establishing an SSH connection from the host with database to the host with the backup catalog. This information will be used by the restore_command to copy WAL segments from the archive to the Postgres Pro pg_wal directory.
To solve this problem, you can use Remote WAL Archive Options.
For example, to restore latest backup on remote system using remote mode through SSH connection to user postgres on host with address 192.168.0.2 via port 2302 and user backup on backup catalog host with address 192.168.0.3 via port 2303, run:
pg_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=postgres --remote-host=192.168.0.2 --remote-port=2302 --archive-host=192.168.0.3 --archive-port=2303 --archive-user=backup
Provided arguments will be used to construct the restore_command:
restore_command = '"install_dir/pg_probackup" archive-get -B "backup_dir" --instanceinstance_name--wal-file-path=%p --wal-file-name=%f --remote-host=192.168.0.3 --remote-port=2303 --remote-user=backup'
Alternatively, you can use the --restore-command option to provide the entire restore_command:
pg_probackup restore -Bbackup_dir--instanceinstance_name--remote-user=postgres --remote-host=192.168.0.2 --remote-port=2302 --restore-command='"install_dir/pg_probackup" archive-get -B "backup_dir" --instanceinstance_name--wal-file-path=%p --wal-file-name=%f --remote-host=192.168.0.3 --remote-port=2303 --remote-user=backup'
Note
The remote mode is currently unavailable for Windows systems.
Running pg_probackup on Parallel Threads
backup, restore, merge, delete, catchup, checkdb, and validate processes can be executed on several parallel threads. This can significantly speed up pg_probackup operation given enough resources (CPU cores, disk, and network bandwidth).
Parallel execution is controlled by the -j/--threads command-line option. For example, to create a backup using four parallel threads, run:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL -j 4
Note
Parallel restore applies only to copying data from the backup catalog to the data directory of the cluster. When Postgres Pro server is started, WAL records need to be replayed, and this cannot be done in parallel.
Configuring pg_probackup
Once the backup catalog is initialized and a new backup instance is added, you can use the pg_probackup.conf configuration file located in the backup_dir/backups/instance_name
For example, backup and checkdb commands use a regular Postgres Pro connection. To avoid specifying connection options each time on the command line, you can set them in the pg_probackup.conf configuration file using the set-config command.
Note
It is not recommended to edit pg_probackup.conf manually.
Initially, pg_probackup.conf contains the following settings:
PGDATA— the path to the data directory of the cluster to back up.system-identifier— the unique identifier of the Postgres Pro instance.
Additionally, you can define remote, retention, logging, and compression settings using the set-config command:
pg_probackup set-config -Bbackup_dir--instanceinstance_name[--external-dirs=external_directory_path] [remote_options] [connection_options] [retention_options] [logging_options]
To view the current settings, run the following command:
pg_probackup show-config -Bbackup_dir--instanceinstance_name
You can override the settings defined in pg_probackup.conf when running pg_probackup commands via the corresponding environment variables and/or command line options.
Specifying Connection Settings
If you define connection settings in the pg_probackup.conf configuration file, you can omit connection options in all the subsequent pg_probackup commands. However, if the corresponding environment variables are set, they get higher priority. The options provided on the command line overwrite both environment variables and configuration file settings.
If nothing is given, the default values are taken. By default pg_probackup tries to use local connection via Unix domain socket (localhost on Windows) and tries to get the database name and the user name from the PGUSER environment variable or the current OS user name.
Managing the Backup Catalog
With pg_probackup, you can manage backups from the command line:
Viewing Backup Information
To view the list of existing backups for every instance, run the command:
pg_probackup show -B backup_dir
pg_probackup displays the list of all the available backups. For example:
BACKUP INSTANCE 'node' =========================================================================================================================================== Instance Version ID Recovery time Mode WAL Mode TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status =========================================================================================================================================== node 10 PYSUE8 2019-10-03 15:51:48+03 FULL ARCHIVE 1/0 16s 9047kB 16MB lz4 4.31 0/12000028 0/12000160 OK node 10 P7XDQV 2018-04-29 05:32:59+03 DELTA STREAM 1/1 11s 19MB 16MB none 1.00 0/15000060 0/15000198 OK node 10 P7XDJA 2018-04-29 05:28:36+03 PTRACK STREAM 1/1 21s 32MB 32MB none 1.00 0/13000028 0/13000198 OK node 10 P7XDHU 2018-04-29 05:27:59+03 PAGE STREAM 1/1 15s 33MB 16MB none 1.00 0/11000028 0/110001D0 OK node 10 P7XDHB 2018-04-29 05:27:15+03 FULL STREAM 1/0 11s 39MB 16MB none 1.00 0/F000028 0/F000198 OK
For each backup, the following information is provided:
Instance— the instance name.Version— Postgres Pro major version.ID— the backup identifier.Recovery time— the earliest moment for which you can restore the state of the database cluster.Mode— the method used to take this backup. Possible values:FULL,PAGE,DELTA,PTRACK.WAL Mode— WAL delivery mode. Possible values:STREAMandARCHIVE.TLI— timeline identifiers of the current backup and its parent.Time— the time it took to perform the backup.Data— the size of the data files in this backup. This value does not include the size of WAL files. For STREAM backups, the total size of the backup can be calculated asData+WAL.WAL— the uncompressed size of WAL files that need to be applied during recovery for the backup to reach a consistent state.compress-alg— compression algorithm used during backup. Possible values:zlib,pglz,lz4,zstd,none.Zratio— compression ratio calculated as “uncompressed-bytes” / “data-bytes”.Start LSN— WAL log sequence number corresponding to the start of the backup process. REDO point for Postgres Pro recovery process to start from.Stop LSN— WAL log sequence number corresponding to the end of the backup process. Consistency point for Postgres Pro recovery process.Status— backup status. Possible values:OK— the backup is complete and valid.DONE— the backup is complete, but was not validated.RUNNING— the backup is in progress.MERGING— the backup is being merged.MERGED— the backup data files were successfully merged, but its metadata is in the process of being updated. Only full backups can have this status.DELETING— the backup files are being deleted.CORRUPT— some of the backup files are corrupt.ERROR— the backup was aborted because of an unexpected error.ORPHAN— the backup is invalid because one of its parent backups is corrupt or missing.HIDDEN_FOR_TEST— a test script marked the backup as nonexistent. (pg_probackup never sets this status by itself.)
You can restore the cluster from the backup only if the backup status is OK or DONE.
To get more detailed information about the backup, run the show command with the backup ID:
pg_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
The sample output is as follows:
#Configuration backup-mode = FULL stream = false compress-alg = zlib compress-level = 1 from-replica = false #Compatibility block-size = 8192 wal-block-size = 8192 checksum-version = 1 program-version = 2.1.3 server-version = 10 #Result backup info timelineid = 1 start-lsn = 0/04000028 stop-lsn = 0/040000f8 start-time = '2017-05-16 12:57:29' end-time = '2017-05-16 12:57:31' end-validation-time = '2017-05-16 12:58:10' recovery-xid = 597 recovery-time = '2017-05-16 12:57:31' expire-time = '2020-05-16 12:57:31' data-bytes = 22288792 wal-bytes = 16777216 uncompressed-bytes = 39961833 pgdata-bytes = 39859393 status = OK parent-backup-id = 'PT8XFX' primary_conninfo = 'user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any'
Detailed output has additional attributes:
compress-alg— compression algorithm used during backup. Possible values:zlib,pglz,lz4,zstd,none.compress-level— compression level used during backup.from-replica— was this backup taken on standby? Possible values:1,0.block-size— the block_size setting of Postgres Pro cluster at the backup start.checksum-version— are data_checksums enabled in the backed up Postgres Pro cluster? Possible values:1,0.program-version— full version of pg_probackup binary used to create the backup.start-time— the backup start time.end-time— the backup end time.end-validation-time— the backup validation end time.expire-time— the point in time when a pinned backup can be removed in accordance with retention policy. This attribute is only available for pinned backups.uncompressed-bytes— the size of data files before adding page headers and applying compression. You can evaluate the effectiveness of compression by comparinguncompressed-bytestodata-bytesif compression if used.pgdata-bytes— the size of Postgres Pro cluster data files at the time of backup. You can evaluate the effectiveness of an incremental backup by comparingpgdata-bytestouncompressed-bytes.recovery-xid— transaction ID at the backup end time.parent-backup-id— ID of the parent backup. Available only for incremental backups.primary_conninfo— libpq connection parameters used to connect to the Postgres Pro cluster to take this backup. The password is not included.note— text note attached to backup.content-crc— CRC32 checksum ofbackup_content.controlfile. It is used to detect corruption of backup metainformation.
You can also get the detailed information about the backup in the JSON format:
pg_probackup show -Bbackup_dir--instanceinstance_name--format=json -i backup_id
The sample output is as follows:
[
{
"instance": "node",
"backups": [
{
"id": "PT91HZ",
"parent-backup-id": "PT8XFX",
"backup-mode": "DELTA",
"wal": "ARCHIVE",
"compress-alg": "zlib",
"compress-level": 1,
"from-replica": false,
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.3",
"server-version": "10",
"current-tli": 16,
"parent-tli": 2,
"start-lsn": "0/8000028",
"stop-lsn": "0/8000160",
"start-time": "2019-06-17 18:25:11+03",
"end-time": "2019-06-17 18:25:16+03",
"end-validation-time": "2019-06-17 18:25:17+03",
"recovery-xid": 0,
"recovery-time": "2019-06-17 18:25:15+03",
"data-bytes": 106733,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
Viewing WAL Archive Information
To view the information about WAL archive for every instance, run the command:
pg_probackup show -Bbackup_dir[--instanceinstance_name] --archive
pg_probackup displays the list of all the available WAL files grouped by timelines. For example:
ARCHIVE INSTANCE 'node' =================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zalg Zratio N backups Status =================================================================================================================================== 5 1 0/B000000 00000005000000000000000B 00000005000000000000000C 2 685kB lz4 48.00 0 OK 4 3 0/18000000 000000040000000000000018 00000004000000000000001A 3 648kB zstd 77.00 0 OK 3 2 0/15000000 000000030000000000000015 000000030000000000000017 3 648kB zstd 77.00 0 OK 2 1 0/B000108 00000002000000000000000B 000000020000000000000015 5 892kB zstd 94.00 1 DEGRADED 1 0 0/0 000000010000000000000001 00000001000000000000000A 10 8774kB zstd 19.00 1 OK
For each timeline, the following information is provided:
TLI— timeline identifier.Parent TLI— identifier of the timeline from which this timeline branched off.Switchpoint— LSN of the moment when the timeline branched off from its parent timeline.Min Segno— the first WAL segment belonging to the timeline.Max Segno— the last WAL segment belonging to the timeline.N segments— number of WAL segments belonging to the timeline.Size— the size that files take on disk.Zalg— compression algorithm used during backup. Possible values:zlib,pglz,lz4,zstd,none.Zratio— compression ratio calculated asN segments*wal_segment_size*wal_block_size/Size.N backups— number of backups belonging to the timeline. To get the details about backups, use the JSON format.Status— status of the WAL archive for this timeline. Possible values:OK— all WAL segments betweenMin SegnoandMax Segnoare present.DEGRADED— some WAL segments betweenMin SegnoandMax Segnoare missing. To find out which files are lost, view this report in the JSON format.
To get more detailed information about the WAL archive in the JSON format, run the command:
pg_probackup show -Bbackup_dir[--instanceinstance_name] --archive --format=json
The sample output is as follows:
[
{
"instance": "replica",
"timelines": [
{
"tli": 5,
"parent-tli": 1,
"switchpoint": "0/B000000",
"min-segno": "00000005000000000000000B",
"max-segno": "00000005000000000000000C",
"n-segments": 2,
"size": 685320,
"zratio": 48.00,
"closest-backup-id": "PXS92O",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 4,
"parent-tli": 3,
"switchpoint": "0/18000000",
"min-segno": "000000040000000000000018",
"max-segno": "00000004000000000000001A",
"n-segments": 3,
"size": 648625,
"zratio": 77.00,
"closest-backup-id": "PXS9CE",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 3,
"parent-tli": 2,
"switchpoint": "0/15000000",
"min-segno": "000000030000000000000015",
"max-segno": "000000030000000000000017",
"n-segments": 3,
"size": 648911,
"zratio": 77.00,
"closest-backup-id": "PXS9CE",
"status": "OK",
"lost-segments": [],
"backups": []
},
{
"tli": 2,
"parent-tli": 1,
"switchpoint": "0/B000108",
"min-segno": "00000002000000000000000B",
"max-segno": "000000020000000000000015",
"n-segments": 5,
"size": 892173,
"zratio": 94.00,
"closest-backup-id": "PXS92O",
"status": "DEGRADED",
"lost-segments": [
{
"begin-segno": "00000002000000000000000D",
"end-segno": "00000002000000000000000E"
},
{
"begin-segno": "000000020000000000000010",
"end-segno": "000000020000000000000012"
}
],
"backups": [
{
"id": "PXS9CE",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 2,
"parent-tli": 0,
"start-lsn": "0/C000028",
"stop-lsn": "0/C000160",
"start-time": "2019-09-13 21:43:26+03",
"end-time": "2019-09-13 21:43:30+03",
"end-validation-time": "2019-09-13 21:43:31+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:43:29+03",
"data-bytes": 104674852,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
},
{
"tli": 1,
"parent-tli": 0,
"switchpoint": "0/0",
"min-segno": "000000010000000000000001",
"max-segno": "00000001000000000000000A",
"n-segments": 10,
"size": 8774805,
"zratio": 19.00,
"closest-backup-id": "",
"status": "OK",
"lost-segments": [],
"backups": [
{
"id": "PXS92O",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "true",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 0,
"start-lsn": "0/4000028",
"stop-lsn": "0/6000028",
"start-time": "2019-09-13 21:37:36+03",
"end-time": "2019-09-13 21:38:45+03",
"end-validation-time": "2019-09-13 21:38:46+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:30+03",
"data-bytes": 25987319,
"wal-bytes": 50331648,
"primary_conninfo": "user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
},
{
"instance": "master",
"timelines": [
{
"tli": 1,
"parent-tli": 0,
"switchpoint": "0/0",
"min-segno": "000000010000000000000001",
"max-segno": "00000001000000000000000B",
"n-segments": 11,
"size": 8860892,
"zratio": 20.00,
"status": "OK",
"lost-segments": [],
"backups": [
{
"id": "PXS92H",
"parent-backup-id": "PXS92C",
"backup-mode": "PAGE",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 1,
"start-lsn": "0/4000028",
"stop-lsn": "0/50000B8",
"start-time": "2019-09-13 21:37:29+03",
"end-time": "2019-09-13 21:37:31+03",
"end-validation-time": "2019-09-13 21:37:32+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:30+03",
"data-bytes": 1328461,
"wal-bytes": 33554432,
"primary_conninfo": "user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
},
{
"id": "PXS92C",
"backup-mode": "FULL",
"wal": "ARCHIVE",
"compress-alg": "none",
"compress-level": 1,
"from-replica": "false",
"block-size": 8192,
"xlog-block-size": 8192,
"checksum-version": 1,
"program-version": "2.1.5",
"server-version": "10",
"current-tli": 1,
"parent-tli": 0,
"start-lsn": "0/2000028",
"stop-lsn": "0/2000160",
"start-time": "2019-09-13 21:37:24+03",
"end-time": "2019-09-13 21:37:29+03",
"end-validation-time": "2019-09-13 21:37:30+03",
"recovery-xid": 0,
"recovery-time": "2019-09-13 21:37:28+03",
"data-bytes": 24871902,
"wal-bytes": 16777216,
"primary_conninfo": "user=backup passfile=/var/lib/pgsql/.pgpass port=5432 sslmode=disable sslcompression=1 target_session_attrs=any",
"status": "OK"
}
]
}
]
}
]
Most fields are consistent with the plain format, with some exceptions:
The size is in bytes.
The
closest-backup-idattribute contains the ID of the most recent valid backup that belongs to one of the previous timelines. You can use this backup to perform point-in-time recovery to this timeline. If such a backup does not exist, this string is empty.The
lost-segmentsarray provides with information about intervals of missing segments inDEGRADEDtimelines. InOKtimelines, thelost-segmentsarray is empty.The
backupsarray lists all backups belonging to the timeline. If the timeline has no backups, this array is empty.
Configuring Retention Policy
With pg_probackup, you can configure retention policy to remove redundant backups, clean up unneeded WAL files, as well as pin specific backups to ensure they are kept for the specified time, as explained in the sections below. All these actions can be combined together in any way.
Removing Redundant Backups
By default, all backup copies created with pg_probackup are stored in the specified backup catalog. To save disk space, you can configure retention policy to remove redundant backup copies.
To configure retention policy, set one or more of the following variables in the pg_probackup.conf file via set-config:
--retention-redundancy=redundancy
Specifies the number of full backup copies to keep in the backup catalog.
--retention-window=window
Defines the earliest point in time for which pg_probackup can complete the recovery. This option is set in the number of days from the current moment. For example, if retention-window=7, pg_probackup must keep at least one backup copy that is older than seven days, with all the corresponding WAL files, and all the backups that follow.
If both --retention-redundancy and --retention-window options are set, both these conditions have to be taken into account when purging the backup catalog. For example, if you set --retention-redundancy=2 and --retention-window=7, pg_probackup has to keep two full backup copies, as well as all the backups required to ensure recoverability for the last seven days:
pg_probackup set-config -Bbackup_dir--instanceinstance_name--retention-redundancy=2 --retention-window=7
It is recommended to always keep at least two last parent full backups to avoid errors when creating incremental backups.
To clean up the backup catalog in accordance with retention policy, you have to run the delete command with retention flags, as shown below, or use the backup command with these flags to process the outdated backup copies right when the new backup is created.
For example, to remove all backup copies that no longer satisfy the defined retention policy, run the following command with the --delete-expired flag:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired
If you would like to also remove the WAL files that are no longer required for any of the backups, you should also specify the --delete-wal flag:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --delete-wal
You can also set or override the current retention policy by specifying --retention-redundancy and --retention-window options directly when running delete or backup commands:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --retention-window=7 --retention-redundancy=2
Since incremental backups require that their parent full backup and all the preceding incremental backups are available, if any of such backups expire, they still cannot be removed while at least one incremental backup in this chain satisfies the retention policy. To avoid keeping expired backups that are still required to restore an active incremental one, you can merge them with this backup using the --merge-expired flag when running backup or delete commands.
Suppose you have backed up the node instance in the backup_dir directory, with the --retention-window option set to 7, and you have the following backups available on April 10, 2019:
BACKUP INSTANCE 'node' ======================================================================================================================================== Instance Version ID Recovery time Mode WAL TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status ======================================================================================================================================== node 10 P7XDHR 2019-04-10 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB none 1.0 0/18000059 0/18000197 OK node 10 P7XDQV 2019-04-08 05:32:59+03 PAGE STREAM 1/0 11s 19MB 16MB none 1.0 0/15000060 0/15000198 OK node 10 P7XDJA 2019-04-03 05:28:36+03 DELTA STREAM 1/0 21s 32MB 16MB none 1.0 0/13000028 0/13000198 OK -------------------------------------------------------retention window-------------------------------------------------------- node 10 P7XDHU 2019-04-02 05:27:59+03 PAGE STREAM 1/0 31s 33MB 16MB none 1.0 0/11000028 0/110001D0 OK node 10 P7XDHB 2019-04-01 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB none 1.0 0/F000028 0/F000198 OK node 10 P7XDFT 2019-03-29 05:26:25+03 FULL STREAM 1/0 11s 200MB 16MB none 1.0 0/D000028 0/D000198 OK
Even though P7XDHB and P7XDHU backups are outside the retention window, they cannot be removed as it invalidates the succeeding incremental backups P7XDJA and P7XDQV that are still required, so, if you run the delete command with the --delete-expired flag, only the P7XDFT full backup will be removed.
With the --merge-expired option, the P7XDJA backup is merged with the underlying P7XDHU and P7XDHB backups and becomes a full one, so there is no need to keep these expired backups anymore:
pg_probackup delete -Bbackup_dir--instancenode--delete-expired --merge-expired pg_probackup show -Bbackup_dir
BACKUP INSTANCE 'node' ======================================================================================================================================= Instance Version ID Recovery time Mode WAL TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status ======================================================================================================================================= node 10 P7XDHR 2019-04-10 05:27:15+03 FULL STREAM 1/0 11s 200MB 16MB none 1.0 0/18000059 0/18000197 OK node 10 P7XDQV 2019-04-08 05:32:59+03 PAGE STREAM 1/0 11s 19MB 16MB none 1.0 0/15000060 0/15000198 OK node 10 P7XDJA 2019-04-03 05:28:36+03 FULL STREAM 1/0 21s 32MB 16MB none 1.0 0/13000028 0/13000198 OK
The Time field for the merged backup displays the time required for the merge.
Pinning Backups
If you need to keep certain backups longer than the established retention policy allows, you can pin them for arbitrary time. For example:
pg_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--ttl=30d
This command sets the expiration time of the specified backup to 30 days starting from the time indicated in its recovery-time attribute.
You can also explicitly set the expiration time for a backup using the --expire-time option. For example:
pg_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--expire-time="2020-01-01 00:00:00+03"
Alternatively, you can use the --ttl and --expire-time options with the backup command to pin the newly created backup:
pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --ttl=30d pg_probackup backup -Bbackup_dir--instanceinstance_name-b FULL --expire-time="2020-01-01 00:00:00+03"
To check if the backup is pinned, run the show command:
pg_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
If the backup is pinned, it has the expire-time attribute that displays its expiration time:
... recovery-time = '2017-05-16 12:57:31' expire-time = '2020-01-01 00:00:00+03' data-bytes = 22288792 ...
You can unpin the backup by setting the --ttl option to zero:
pg_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id--ttl=0
Note
A pinned incremental backup implicitly pins all its parent backups. If you unpin such a backup later, its implicitly pinned parents will also be automatically unpinned.
Configuring WAL Archive Retention Policy
When continuous WAL archiving is enabled, archived WAL segments can take a lot of disk space. Even if you delete old backup copies from time to time, the --delete-wal flag can purge only those WAL segments that do not apply to any of the remaining backups in the backup catalog. However, if point-in-time recovery is critical only for the most recent backups, you can configure WAL archive retention policy to keep WAL archive of limited depth and win back some more disk space.
To configure WAL archive retention policy, you have to run the set-config command with the --wal-depth option that specifies the number of backups that can be used for PITR. This setting applies to all the timelines, so you should be able to perform PITR for the same number of backups on each timeline, if available. Pinned backups are not included into this count: if one of the latest backups is pinned, pg_probackup ensures that PITR is possible for one extra backup.
To remove WAL segments that do not satisfy the defined WAL archive retention policy, you simply have to run the delete or backup command with the --delete-wal flag. For archive backups, WAL segments between Start LSN and Stop LSN are always kept intact, so such backups remain valid regardless of the --wal-depth setting and can still be restored, if required.
You can also use the --wal-depth option with the delete and backup commands to override the previously defined WAL archive retention policy and purge old WAL segments on the fly.
Suppose you have backed up the node instance in the backup_dir directory and configured continuous WAL archiving:
pg_probackup show -Bbackup_dir--instancenode
BACKUP INSTANCE 'node' ======================================================================================================================================= Instance Version ID Recovery Time Mode WAL Mode TLI Time Data WAL Zalg Zratio Start LSN Stop LSN Status ======================================================================================================================================= node 11 PZ9442 2019-10-12 10:43:21+03 DELTA STREAM 1/0 10s 121kB 16MB none 1.00 0/46000028 0/46000160 OK node 11 PZ943L 2019-10-12 10:43:04+03 FULL STREAM 1/0 10s 180MB 32MB none 1.00 0/44000028 0/44000160 OK node 11 PZ7YR5 2019-10-11 19:49:56+03 DELTA STREAM 1/1 10s 112kB 32MB none 1.00 0/41000028 0/41000160 OK node 11 PZ7YMP 2019-10-11 19:47:16+03 DELTA STREAM 1/1 10s 376kB 32MB none 1.00 0/3E000028 0/3F0000B8 OK node 11 PZ7YK2 2019-10-11 19:45:45+03 FULL STREAM 1/0 11s 180MB 16MB none 1.00 0/3C000028 0/3C000198 OK node 11 PZ7YFO 2019-10-11 19:43:04+03 FULL STREAM 1/0 10s 30MB 16MB none 1.00 0/2000028 0/200ADD8 OK
You can check the state of the WAL archive by running the show command with the --archive flag:
pg_probackup show -B backup_dir --instance node --archive
ARCHIVE INSTANCE 'node' ==================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zalg Zratio N backups Status ==================================================================================================================================== 1 0 0/0 000000010000000000000001 000000010000000000000047 71 36MB zstd 31.00 6 OK
WAL purge without --wal-depth cannot achieve much, only one segment is removed:
pg_probackup delete -B backup_dir --instance node --delete-wal
ARCHIVE INSTANCE 'node' ===================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zalg Zratio N backups Status ===================================================================================================================================== 1 0 0/0 000000010000000000000002 000000010000000000000047 70 34MB zstd 32.00 6 OK
If you would like, for example, to keep only those WAL segments that can be applied to the latest valid backup, set the --wal-depth option to 1:
pg_probackup delete -B backup_dir --instance node --delete-wal --wal-depth=1
ARCHIVE INSTANCE 'node' ===================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zalg Zratio N backups Status ===================================================================================================================================== 1 0 0/0 000000010000000000000046 000000010000000000000047 2 143kB zstd 228.00 6 OK
Alternatively, you can use the --wal-depth option with the backup command:
pg_probackup backup -B backup_dir --instance node -b DELTA --wal-depth=1 --delete-wal
ARCHIVE INSTANCE 'node' ==================================================================================================================================== TLI Parent TLI Switchpoint Min Segno Max Segno N segments Size Zalg Zratio N backups Status ==================================================================================================================================== 1 0 0/0 000000010000000000000048 000000010000000000000049 1 72kB zstd 228.00 7 OK
Merging Backups
As you take more and more incremental backups, the total size of the backup catalog can substantially grow. To save disk space, you can merge incremental backups to their parent full backup by running the merge command, specifying the backup ID of the most recent incremental backup you would like to merge:
pg_probackup merge -Bbackup_dir--instanceinstance_name-ibackup_id
This command merges backups that belong to a common incremental backup chain. If you specify a full backup, it will be merged with its first incremental backup. If you specify an incremental backup, it will be merged to its parent full backup, together with all incremental backups between them. Once the merge is complete, the full backup takes in all the merged data, and the incremental backups are removed as redundant. Thus, the merge operation is virtually equivalent to retaking a full backup and removing all the outdated backups, but it allows you to save much time, especially for large data volumes, as well as I/O and network traffic if you are using pg_probackup in the remote mode.
Before the merge, pg_probackup validates all the affected backups to ensure that they are valid. You can check the current backup status by running the show command with the backup ID:
pg_probackup show -Bbackup_dir--instanceinstance_name-ibackup_id
If the merge is still in progress, the backup status is displayed as MERGING. For full backups, it can also be shown as MERGED while the metadata is being updated at the final stage of the merge. The merge is idempotent, so you can restart the merge if it was interrupted.
Deleting Backups
To delete a backup that is no longer required, run the following command:
pg_probackup delete -Bbackup_dir--instanceinstance_name-ibackup_id
This command will delete the backup with the specified backup_id, together with all the incremental backups that descend from backup_id, if any. This way you can delete some recent incremental backups, retaining the underlying full backup and some of the incremental backups that follow it.
To delete obsolete WAL files that are not necessary to restore any of the remaining backups, use the --delete-wal flag:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-wal
To delete backups that are expired according to the current retention policy, use the --delete-expired flag:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired
Expired backups cannot be removed while at least one incremental backup that satisfies the retention policy is based on them. If you would like to minimize the number of backups still required to keep incremental backups valid, specify the --merge-expired flag when running this command:
pg_probackup delete -Bbackup_dir--instanceinstance_name--delete-expired --merge-expired
In this case, pg_probackup searches for the oldest incremental backup that satisfies the retention policy and merges this backup with the underlying full and incremental backups that have already expired, thus making it a full backup. Once the merge is complete, the remaining expired backups are deleted.
Before merging or deleting backups, you can run the delete command with the --dry-run flag, which displays the status of all the available backups according to the current retention policy, without performing any irreversible actions.
To delete all backups with specific status, use the --status:
pg_probackup delete -Bbackup_dir--instanceinstance_name--status=ERROR
Deleting backups by status ignores established retention policies.
Cloning and Synchronizing Postgres Pro Instance
pg_probackup can create a copy of a Postgres Pro instance directly, without using the backup catalog. To do this, you can run the catchup command. It can be useful in the following cases:
To add a new standby server.
Usually, pg_basebackup is used to create a copy of a Postgres Pro instance. If the data directory of the destination instance is empty, the
catchupcommand works similarly, but it can be faster if run in parallel mode.To have a fallen-behind standby server “catch up” with master.
Under write-intensive load, replicas may fail to replay WAL fast enough to keep up with master and hence may lag behind. A usual solution to create a new replica and switch to it requires a lot of extra space and data transfer. The
catchupcommand allows you to update an existing replica much faster by bringing differences from master.
catchup is different from other pg_probackup operations:
The backup catalog is not required.
STREAM WAL delivery mode is only supported.
Copying external directories is not supported.
DDL commands CREATE TABLESPACE/DROP TABLESPACE cannot be run simultaneously with
catchup.catchuptakes configuration files, such aspostgresql.conf,postgresql.auto.conf, orpg_hba.conf, from the source server and overwrites them on the target server. The--exclude-pathoption allows you to keep the configuration files intact.
To prepare for cloning/synchronizing a Postgres Pro instance, set up the source server as follows:
Configure the database cluster for the instance to copy.
To copy from a remote server, configure the remote mode.
To use the PTRACK catchup mode, set up PTRACK backups.
Before cloning/synchronizing a Postgres Pro instance, ensure that the source server is running and accepting connections. To clone/sync a Postgres Pro instance, on the server with the destination instance, you can run the catchup command as follows:
pg_probackup catchup -bcatchup_mode--source-pgdata=path_to_pgdata_on_remote_server--destination-pgdata=path_to_local_dir--stream [connection_options] [remote_options]
Where catchup_mode can take one of the following values:
FULL— creates a full copy of the Postgres Pro instance. The data directory of the destination instance must be empty for this mode.DELTA— reads all data files in the data directory and creates an incremental copy for pages that have changed since the destination instance was shut down.PTRACK— tracking page changes on the fly, only reads and copies pages that have changed since the point of divergence of the source and destination instances.Warning
PTRACK catchup mode requires PTRACK not earlier than 2.0 and hence, Postgres Pro not earlier than 11.
By specifying the --stream option, you can set STREAM WAL delivery mode of copying, which will include all the necessary WAL files by streaming them from the server via replication protocol.
You can use connection_options to specify the connection to the source database cluster. If it is located on a different server, also specify remote_options.
If the source database cluster contains tablespaces that must be located in a different directory, additionally specify the --tablespace-mapping option:
pg_probackup catchup -bcatchup_mode--source-pgdata=path_to_pgdata_on_remote_server--destination-pgdata=path_to_local_dir--stream --tablespace-mapping=OLDDIR=NEWDIR
To run the catchup command on parallel threads, specify the number of threads with the --threads option:
pg_probackup catchup -bcatchup_mode--source-pgdata=path_to_pgdata_on_remote_server--destination-pgdata=path_to_local_dir--stream --threads=num_threads
Before cloning/synchronising a Postgres Pro instance, you can run the catchup command with the --dry-run flag to estimate the size of data files to be transferred, but make no changes on disk:
pg_probackup catchup -bcatchup_mode--source-pgdata=path_to_pgdata_on_remote_server--destination-pgdata=path_to_local_dir--stream --dry-run
For example, assume that a remote standby server with the Postgres Pro instance having /replica-pgdata data directory has fallen behind. To sync this instance with the one in /master-pgdata data directory, you can run the catchup command in the PTRACK mode on four parallel threads as follows:
pg_probackup catchup --source-pgdata=/master-pgdata --destination-pgdata=/replica-pgdata -p 5432 -d postgres -U remote-postgres-user --stream --backup-mode=PTRACK --remote-host=remote-hostname --remote-user=remote-unix-username -j 4 --exclude-path=postgresql.conf --exclude-path=postgresql.auto.conf --exclude-path=pg_hba.conf --exclude-path=pg_ident.conf
Note that in this example, the configuration files will not be overwritten during synchronization.
Another example shows how you can add a new remote standby server with the Postgres Pro data directory /replica-pgdata by running the catchup command in the FULL mode on four parallel threads:
pg_probackup catchup --source-pgdata=/master-pgdata --destination-pgdata=/replica-pgdata -p 5432 -d postgres -U remote-postgres-user --stream --backup-mode=FULL --remote-host=remote-hostname --remote-user=remote-unix-username -j 4
Command-Line Reference
Commands
This section describes pg_probackup commands. Optional parameters are enclosed in square brackets. For detailed parameter descriptions, see the section Options.
version
pg_probackup version
Prints pg_probackup version and edition, as well as Postgres Pro version and edition.
help
pg_probackup help [command]
Displays the synopsis of pg_probackup commands. If one of the pg_probackup commands is specified, shows detailed information about the options that can be used with this command.
init
pg_probackup init -Bbackup_dir[--skip-if-exists] [--help] [logging_options]
Initializes the backup catalog in backup_dir that will store backup copies, WAL archive, and meta information for the backed up database clusters. If the specified backup_dir already exists, it must be empty. Otherwise, pg_probackup displays a corresponding error message. You can ignore this error by specifying the --skip-if-exists option. Although the backup will not be initialized, the application will return 0 code.
For details, see the section Initializing the Backup Catalog.
add-instance
pg_probackup add-instance -Bbackup_dir-Ddata_dir--instanceinstance_name[--skip-if-exists] [--help] [logging_options]
Initializes a new backup instance inside the backup catalog backup_dir and generates the pg_probackup.conf configuration file that controls pg_probackup settings for the cluster with the specified data_dir data directory. If the catalog was already initialized, you can ignore the error by specifying --skip-if-exists.
For details, see the section Adding a New Backup Instance.
del-instance
pg_probackup del-instance -Bbackup_dir--instanceinstance_name[--help] [logging_options]
Deletes all backups and WAL files associated with the specified instance.
set-config
pg_probackup set-config -Bbackup_dir--instanceinstance_name[--help] [--pgdata=pgdata-path] [--retention-redundancy=redundancy][--retention-window=window][--wal-depth=wal_depth] [--compress-algorithm=compression_algorithm] [--compress-level=compression_level] [-ddbname] [-hhost] [-pport] [-Uusername] [--archive-timeout=timeout] [--external-dirs=external_directory_path] [--restore-command=cmdline] [remote_options] [remote_wal_archive_options] [logging_options]
Adds the specified connection, compression, retention, logging, and external directory settings into the pg_probackup.conf configuration file, or modifies the previously defined values.
For all available settings, see the Options section.
It is not recommended to edit pg_probackup.conf manually.
set-backup
pg_probackup set-backup -Bbackup_dir--instanceinstance_name-ibackup_id{--ttl=ttl| --expire-time=time} [--note=backup_note] [--help] [logging_options]
Sets the provided backup-specific settings into the backup.control configuration file, or modifies the previously defined values.
--note=backup_noteSets the text note for backup copy. If
backup_notecontain newline characters, then only substring before first newline character will be saved. Max size of text note is 1 KB. The'none'value removes current note.
For all available pinning settings, see the section Pinning Options.
show-config
pg_probackup show-config -Bbackup_dir--instanceinstance_name[--format=plain|json] [--no-scale-units] [logging_options]
Displays all the current pg_probackup configuration settings, including those that are specified in the pg_probackup.conf configuration file located in the backup_dir/backups/instance_name--format=json option to get the result in the JSON format. By default, configuration settings are shown as plain text.
You can also specify the --no-scale-units option to display time and memory configuration settings in their base (unscaled) units. Otherwise, the values are scaled to larger units for optimal display. For example, if archive-timeout is 300, then 5min is displayed, but if archive-timeout is 301, then 301s is displayed. Also, if the --no-scale-units option is specified, configuration settings are displayed without units and for the JSON format, numeric and boolean values are not enclosed in quotes. This facilitates parsing the output.
To edit pg_probackup.conf, use the set-config command.
show
pg_probackup show -Bbackup_dir[--help] [--instanceinstance_name[-ibackup_id| --archive]] [--format=plain|json] [--no-color] [--show-symlinks] [logging_options]
Shows the contents of the backup catalog. If instance_name and backup_id are specified, shows detailed information about this backup. If the --archive option is specified, shows the contents of WAL archive of the backup catalog.
By default, the contents of the backup catalog is shown as plain text. You can specify the --format=json option to get the result in the JSON format. If --no-color flag is used, then the output is not colored.
If the --show-symlinks option is specified, the command also shows the links between merged backups and the original full backups that incremental backups were merged to.
For details on usage, see the sections Managing the Backup Catalog and Viewing WAL Archive Information.
backup
pg_probackup backup -Bbackup_dir-bbackup_mode--instanceinstance_name[--help] [-jnum_threads] [--progress] [-C] [--stream [-S slot_name] [--temp-slot[=true|false|on|off]]] [--backup-pg-log] [--no-validate] [--skip-block-validation] [-w --no-password] [-W --password] [--write-rate-limit=bitrate] [--archive-timeout=timeout] [--external-dirs=external_directory_path] [--no-sync] [--note=backup_note] [connection_options] [compression_options] [remote_options] [retention_options] [pinning_options] [logging_options]
Creates a backup copy of the Postgres Pro instance.
-bmode--backup-mode=modeSpecifies the backup mode to use. Possible values are:
FULL,DELTA,PAGE, andPTRACK.-C--smooth-checkpointSpreads out the checkpoint over a period of time. By default, pg_probackup tries to complete the checkpoint as soon as possible.
--streamMakes a STREAM backup, which includes all the necessary WAL files by streaming them from the database server via replication protocol.
--temp-slot[=true|false|on|off]Creates a temporary physical replication slot for streaming WAL from the backed up Postgres Pro instance.
--temp-slotis enabled by default. It ensures that all the required WAL segments remain available if WAL is rotated while the backup is in progress. This flag can only be used together with the--streamflag. The default slot name ispg_probackup_slot. To change it, use the--slot/-Soption and explicitly specify--temp-slotor--temp-slot=.true|on-Sslot_name--slot=slot_nameSpecifies the replication slot to connect to for WAL streaming. This option can only be used together with the
--streamflag.--backup-pg-logIncludes the log directory into the backup. This directory usually contains log messages. By default, log directory is excluded.
-Eexternal_directory_path--external-dirs=external_directory_pathIncludes the specified directory into the backup by recursively copying its contents into a separate subdirectory in the backup catalog. This option is useful to back up scripts, SQL dump files, and configuration files located outside of the data directory. If you would like to back up several external directories, separate their paths by a colon on Unix and a semicolon on Windows.
--write-rate-limit=bitrateSets the rate of writing data to disk, in MBps or GBps. The default unit is MBps. For example:
--write-rate-limit=1GBpsor--write-rate-limit=100(MBps). The default value is 0 — no limitation.If this option is specified, the following information is displayed at the end of the backup:
written— the amount of data written, in MB.total time— the time that elapsed between the first and last writes, in seconds. Note that this is not the total backup time.sleep time— the amount of forced delay time, in seconds.average rate— the actual average write rate, in MBps.
For example:
INFO: Rate limit: written 14975.445 MB, total time 17.163 s, sleep time 2.370 s, average rate 872.560715 MBps
--archive-timeout=wait_timeSets the timeout for WAL segment archiving and streaming, in seconds. By default, pg_probackup waits 300 seconds.
--skip-block-validationDisables block-level checksum verification to speed up the backup process.
--no-validateSkips automatic validation after the backup is taken. You can use this flag if you validate backups regularly and would like to save time when running backup operations.
--no-syncDo not sync backed up files to disk. You can use this flag to speed up the backup process. Using this flag can result in data corruption in case of operating system or hardware crash. If you use this option, it is recommended to run the validate command once the backup is complete to detect possible issues.
--note=backup_noteSets the text note for backup copy. If
backup_notecontain newline characters, then only substring before first newline character will be saved. Max size of text note is 1 KB. The'none'value removes current note.
Additionally, connection options, retention options, pinning options, remote mode options, compression options, logging options, and common options can be used.
For details on usage, see the section Creating a Backup.
restore
pg_probackup restore -Bbackup_dir--instanceinstance_name[--help] [-Ddata_dir] [-ibackup_id] [-jnum_threads] [--progress] [-TOLDDIR=NEWDIR] [--external-mapping=OLDDIR=NEWDIR] [--skip-external-dirs] [-R | --restore-as-replica] [--no-validate] [--skip-block-validation] [--force] [--no-sync] [--restore-command=cmdline] [--primary-conninfo=primary_conninfo] [-S | --primary-slot-name=slot_name] [-Xwal_dir| --waldir=wal_dir] [recovery_target_options] [logging_options] [remote_options] [partial_restore_options] [remote_wal_archive_options]
Restores the Postgres Pro instance from a backup copy located in the backup_dir backup catalog. If you specify a recovery target option, pg_probackup finds the closest backup and restores it to the specified recovery target. If neither the backup ID nor recovery target options are provided, pg_probackup uses the most recent backup to perform the recovery.
-R--restore-as-replicaCreates a minimal recovery configuration file to facilitate setting up a standby server. If the replication connection requires a password, you must specify the password manually in the primary_conninfo parameter as it is not included. For Postgres Pro 11 or lower, recovery settings are written into the
recovery.conffile. Starting from Postgres Pro 12, pg_probackup writes these settings into theprobackup_recovery.conffile in the data directory, and then includes them into thepostgresql.auto.confwhen the cluster is is started.--primary-conninfo=primary_conninfoSets the primary_conninfo parameter to the specified value. This option will be ignored unless the
-Rflag is specified.Example:
--primary-conninfo="host=192.168.1.50 port=5432 user=foo password=foopass"-S--primary-slot-name=slot_nameSets the primary_slot_name parameter to the specified value. This option will be ignored unless the
-Rflag is specified.-TOLDDIR=NEWDIR--tablespace-mapping=OLDDIR=NEWDIRRelocates the tablespace from the
OLDDIRto theNEWDIRdirectory at the time of recovery. BothOLDDIRandNEWDIRmust be absolute paths. If the path contains the equals sign (=), escape it with a backslash. This option can be specified multiple times for multiple tablespaces.--external-mapping=OLDDIR=NEWDIRRelocates an external directory included into the backup from the
OLDDIRto theNEWDIRdirectory at the time of recovery. BothOLDDIRandNEWDIRmust be absolute paths. If the path contains the equals sign (=), escape it with a backslash. This option can be specified multiple times for multiple directories.--skip-external-dirsSkip external directories included into the backup with the
--external-dirsoption. The contents of these directories will not be restored.--skip-block-validationDisables block-level checksum verification to speed up validation. During automatic validation before the restore only file-level checksums will be verified.
--no-validateSkips backup validation. You can use this flag if you validate backups regularly and would like to save time when running restore operations.
--restore-command=cmdlineSets the restore_command parameter to the specified command. For example:
--restore-command='cp /mnt/server/archivedir/%f "%p"'--forceAllows to ignore an invalid status of the backup. You can use this flag if you need to restore the Postgres Pro cluster from a corrupt or an invalid backup. Use with caution. If
PGDATAcontains a non-empty directory with system ID different from that of the backup being restored, incremental restore with this flag overwrites the directory contents (while an error occurs without the flag). If tablespaces are remapped through the--tablespace-mappingoption into non-empty directories, the contents of such directories will be deleted.--no-syncDo not sync restored files to disk. You can use this flag to speed up restore process. Using this flag can result in data corruption in case of operating system or hardware crash. If it happens, you have to run the restore command again.
-Xwal_dir--waldir=wal_dirSets the directory to write WAL files to. By default WAL files will be placed in the
pg_walsubdirectory of the target directory, but this option can be used to place them elsewhere.wal_dirmust be an absolute path, which must not already exist, but if it does, it must be empty.
Additionally, recovery target options, remote mode options, remote WAL archive options, logging options, partial restore options, and common options can be used.
For details on usage, see the section Restoring a Cluster.
checkdb
pg_probackup checkdb [-Bbackup_dir] [--instanceinstance_name] [-Ddata_dir] [--help] [-jnum_threads] [--progress] [--amcheck [--skip-block-validation] [--checkunique] [--heapallindexed]] [connection_options] [logging_options]
Verifies the Postgres Pro database cluster correctness by detecting physical and logical corruption.
--amcheckPerforms logical verification of indexes for the specified Postgres Pro instance if no corruption was found while checking data files. You must have the amcheck extension or the amcheck_next extension installed in the database to check its indexes. For databases without amcheck, index verification will be skipped. Additional options
--checkuniqueand--heapallindexedare effective depending on the version of amcheck installed.--checkuniqueVerifies unique constraints during logical verification of indexes. You can use this flag only together with the
--amcheckflag when the amcheck extension is installed in the database.The verification of unique constraints is only possible if in the version of the amcheck extension you are using, the
bt_index_checkfunction takes thecheckuniqueparameter.--heapallindexedChecks that all heap tuples that should be indexed are actually indexed. You can use this flag only together with the
--amcheckflag.This check is only possible if in the version of the amcheck/amcheck_next extension you are using, the
bt_index_checkfunction takes theheapallindexedparameter.--skip-block-validationSkip validation of data files. You can use this flag only together with the
--amcheckflag, so that only logical verification of indexes is performed.
Additionally, connection options and logging options can be used.
For details on usage, see the section Verifying a Cluster.
validate
pg_probackup validate -Bbackup_dir[--help] [--instanceinstance_name] [-ibackup_id] [-jnum_threads] [--progress] [--skip-block-validation] [recovery_target_options] [logging_options]
Verifies that all the files required to restore the cluster are present and are not corrupt. If instance_name is not specified, pg_probackup validates all backups available in the backup catalog. If you specify the instance_name without any additional options, pg_probackup validates all the backups available for this backup instance. If you specify the instance_name with a recovery target option and/or a backup_id, pg_probackup checks whether it is possible to restore the cluster using these options.
For details, see the section Validating a Backup.
merge
pg_probackup merge -Bbackup_dir--instanceinstance_name-ibackup_id[--help] [-jnum_threads] [--progress] [--no-validate] [--no-sync] [logging_options]
Merges backups that belong to a common incremental backup chain. If you specify a full backup, it will be merged with its first incremental backup. If you specify an incremental backup, it will be merged to its parent full backup, together with all incremental backups between them. Once the merge is complete, the full backup takes in all the merged data, and the incremental backups are removed as redundant.
--no-validateSkips automatic validation before and after merge.
--no-syncDo not sync merged files to disk. You can use this flag to speed up the merge process. Using this flag can result in data corruption in case of operating system or hardware crash.
For details, see the section Merging Backups.
delete
pg_probackup delete -Bbackup_dir--instanceinstance_name[--help] [-jnum_threads] [--progress] [--retention-redundancy=redundancy][--retention-window=window][--wal-depth=wal_depth] [--delete-wal] {-ibackup_id| --delete-expired [--merge-expired] | --merge-expired | --status=backup_status} [--dry-run] [--no-validate] [--no-sync] [logging_options]
Deletes backup with specified backup_id or launches the retention purge of backups and archived WAL that do not satisfy the current retention policies.
--no-validateSkips automatic validation before and after retention merge.
--no-syncDo not sync merged files to disk. You can use this flag to speed up the retention merge process. Using this flag can result in data corruption in case of operating system or hardware crash.
For details, see the sections Deleting Backups, Retention Options, and Configuring Retention Policy.
archive-push
pg_probackup archive-push -Bbackup_dir--instanceinstance_name--wal-file-name=wal_file_name[--wal-file-path=wal_file_path] [--help] [--no-sync] [--compress] [--no-ready-rename] [--overwrite] [-jnum_threads] [--batch-size=batch_size] [--archive-timeout=timeout] [--compress-algorithm=compression_algorithm] [--compress-level=compression_level] [remote_options] [logging_options]
Copies WAL files into the corresponding subdirectory of the backup catalog and validates the backup instance by instance_name and system-identifier. If parameters of the backup instance and the cluster do not match, this command fails with the following error message: Refuse to push WAL segment segment_name into archive. Instance parameters mismatch.
If the files to be copied already exists in the backup catalog, pg_probackup computes and compares their checksums. If the checksums match, archive-push skips the corresponding file and returns a successful execution code. Otherwise, archive-push fails with an error. If you would like to replace WAL files in the case of checksum mismatch, run the archive-push command with the --overwrite flag.
Each file is copied to a temporary file with the .part suffix. If the temporary file already exists, pg_probackup will wait archive_timeout seconds before discarding it. After the copy is done, atomic rename is performed. This algorithm ensures that a failed archive-push will not stall continuous archiving and that concurrent archiving from multiple sources into a single WAL archive has no risk of archive corruption.
The postgres server requests WAL segments one at a time. To speed up archiving, you can specify the --batch-size option to copy WAL segments in batches of the specified size. If --batch-size option is used, then you can also specify the -j option to copy the batch of WAL segments on multiple threads.
WAL segments copied to the archive are synced to disk unless the --no-sync flag is used.
You can use archive-push in the archive_command Postgres Pro parameter to set up continuous WAL archiving.
For details, see sections Archiving Options and Compression Options.
archive-get
pg_probackup archive-get -Bbackup_dir--instanceinstance_name--wal-file-path=wal_file_path--wal-file-name=wal_file_name[-jnum_threads] [--batch-size=batch_size] [--prefetch-dir=prefetch_dir_path] [--no-validate-wal] [--help] [remote_options] [logging_options]
Copies WAL files from the corresponding subdirectory of the backup catalog to the cluster's write-ahead log location. This command is automatically set by pg_probackup as part of the restore_command when restoring backups using a WAL archive. You do not need to set it manually.
The postgres server requests WAL segments one at a time. To speed up recovery, you can specify the --batch-size option to copy WAL segments in batches of the specified size. If --batch-size option is used, then you can also specify the -j option to copy the batch of WAL segments on multiple threads.
For details, see section Archiving Options.
catchup
pg_probackup catchup -bcatchup_mode--source-pgdata=path_to_pgdata_on_remote_server--destination-pgdata=path_to_local_dir[--help] [-j | --threads=num_threads] [--dry-run] [--write-rate-limit=bitrate] [--stream [--temp-slot[=true|false|on|off]] [-P | --perm-slot] [-S | --slot=slot_name]] [--exclude-path=PATHNAME] [-TOLDDIR=NEWDIR] [-X | --waldir=wal_dir] [connection_options] [remote_options] [logging_options]
Creates a copy of a Postgres Pro instance without using the backup catalog.
-bcatchup_mode--backup-mode=catchup_modeSpecifies the catchup mode to use. Possible values are:
FULL,DELTA, andPTRACK.--source-pgdata=path_to_pgdata_on_remote_serverSpecifies the path to the data directory of the instance to be copied. The path can be local or remote.
--destination-pgdata=path_to_local_dirSpecifies the path to the local data directory to copy to.
-jnum_threads--threads=num_threadsSets the number of parallel threads for
catchupprocess.--streamCopies the instance in STREAM WAL delivery mode, including all the necessary WAL files by streaming them from the server via replication protocol. For
catchup, it is enabled by default.--dry-runDisplays the total size of the files to be transferred by
catchup. This flag initiates a trial run ofcatchup, which does not actually create, delete or move files on disk. WAL streaming is skipped with--dry-run. This flag also allows you to check that all the options are correct and cloning/synchronising is ready to run.--write-rate-limit=bitrateSets the rate of writing data to disk, in MBps or GBps. The default unit is MBps. For example:
--write-rate-limit=1GBpsor--write-rate-limit=100(MBps). The default value is 0 — no limitation.If this option is specified, the following information is displayed at the end of the
catchupoperation:written— the amount of data written, in MB.total time— the time that elapsed between the first and last writes, in seconds. Note that this is not the total duration of thecatchupoperation.sleep time— the amount of forced delay time, in seconds.average rate— the actual average write rate, in MBps.
For example:
INFO: Rate limit: written 14975.445 MB, total time 17.163 s, sleep time 2.370 s, average rate 872.560715 MBps
-x=path_prefix--exclude-path=path_prefixSpecifies a prefix for files to exclude from the synchronization of Postgres Pro instances during copying. The prefix must contain a path relative to the data directory of an instance. If the prefix specifies a directory, all files in this directory will not be synchronized.
Warning
This option is dangerous since excluding files from synchronization can result in incomplete synchronization; use with care.
--temp-slot[=true|false|on|off]Creates a temporary physical replication slot for streaming WAL from the Postgres Pro instance being copied.
--temp-slotis enabled by default. It ensures that all the required WAL segments remain available if WAL is rotated while the backup is in progress. This flag can only be used together with the--streamflag and cannot be used together with the--perm-slotflag. The default slot name ispg_probackup_slot. To change it, use the--slot/-Soption and explicitly specify--temp-slotor--temp-slot=.true|on-P--perm-slotCreates a permanent physical replication slot for streaming WAL from the Postgres Pro instance being copied. This flag can only be used together with the
--streamflag and cannot be used together with the--temp-slotflag. The default slot name ispg_probackup_perm_slot, which can be changed using the--slot/-Soption.-Sslot_name--slot=slot_nameSpecifies the replication slot to connect to for WAL streaming. This option can only be used together with the
--streamflag.-TOLDDIR=NEWDIR--tablespace-mapping=OLDDIR=NEWDIRRelocates the tablespace from the
OLDDIRto theNEWDIRdirectory at the time of recovery. BothOLDDIRandNEWDIRmust be absolute paths. If the path contains the equals sign (=), escape it with a backslash. This option can be specified multiple times for multiple tablespaces.-Xwal_dir--waldir=wal_dirSets the directory to write WAL files to. By default WAL files will be placed in the
pg_walsubdirectory of the target directory, but this option can be used to place them elsewhere.wal_dirmust be an absolute path, which must not already exist, but if it does, it must be empty to performcatchupwith--catchup-mode=FULL.
Additionally, connection options, remote mode options can be used.
For details on usage, see the section Cloning and Synchronizing Postgres Pro Instance.
Options
This section describes command-line options for pg_probackup commands. If the option value can be derived from an environment variable, this variable is specified below the command-line option, in the uppercase. Some values can be taken from the pg_probackup.conf configuration file located in the backup catalog.
For details, see the section called “Configuring pg_probackup”.
If an option is specified using more than one method, command-line input has the highest priority, while the pg_probackup.conf settings have the lowest priority.
Common Options
The list of general options.
-Bdirectory--backup-path=directoryBACKUP_PATHSpecifies the absolute path to the backup catalog. Backup catalog is a directory where all backup files and meta information are stored. Since this option is required for most of the pg_probackup commands, you are recommended to specify it once in the
BACKUP_PATHenvironment variable. In this case, you do not need to use this option each time on the command line.-Ddirectory--pgdata=directoryPGDATASpecifies the absolute path to the data directory of the database cluster. This option is mandatory only for the add-instance command. Other commands can take its value from the
PGDATAenvironment variable, or from thepg_probackup.confconfiguration file.-ibackup_id--backup-id=backup_idSpecifies the unique identifier of the backup.
-jnum_threads--threads=num_threadsSets the number of parallel threads for
backup,restore,merge,validate,checkdb, andarchive-pushprocesses.--progressShows the progress of operations.
--helpShows detailed information about the options that can be used with this command.
Recovery Target Options
If continuous WAL archiving is configured, you can use one of these options together with restore or validate commands to specify the moment up to which the database cluster must be restored or validated.
--recovery-target=immediate|latestDefines when to stop the recovery:
The
immediatevalue stops the recovery after reaching the consistent state of the specified backup, or the latest available backup if the-i/--backup-idoption is omitted. This is the default behavior for STREAM backups.The
latestvalue continues the recovery until all WAL segments available in the archive are applied. Setting this value of--recovery-targetalso sets--recovery-target-timelinetolatest.
--recovery-target-timeline=timelineSpecifies a particular timeline to be used for recovery:
current— the timeline of the specified backup, default.
latest— the timeline of the latest available backup.A numeric value.
--recovery-target-lsn=lsnSpecifies the LSN of the write-ahead log location up to which recovery will proceed.
--recovery-target-name=recovery_target_nameSpecifies a named savepoint up to which to restore the cluster.
--recovery-target-time=timeSpecifies the timestamp up to which recovery will proceed. If the time zone offset is not specified, the local time zone is used.
Example:
--recovery-target-time="2020-01-01 00:00:00+03"--recovery-target-xid=xidSpecifies the transaction ID up to which recovery will proceed.
--recovery-target-inclusive=booleanSpecifies whether to stop just after the specified recovery target (
true), or just before the recovery target (false). This option can only be used together with--recovery-target-name,--recovery-target-time,--recovery-target-lsnor--recovery-target-xidoptions. The default depends on the recovery_target_inclusive parameter.--recovery-target-action=pause|promote|shutdownSpecifies recovery_target_action the server should take when the recovery target is reached.
Default:
pause
Retention Options
You can use these options together with backup and delete commands.
For details on configuring retention policy, see the section Configuring Retention Policy.
--retention-redundancy=redundancySpecifies the number of full backup copies to keep in the data directory. Must be a non-negative integer. The zero value disables this setting.
Default:
0--retention-window=windowNumber of days of recoverability. Must be a non-negative integer. The zero value disables this setting.
Default:
0--wal-depth=wal_depthNumber of latest valid backups on every timeline that must retain the ability to perform PITR. Must be a non-negative integer. The zero value disables this setting.
Default:
0--delete-walDeletes WAL files that are no longer required to restore the cluster from any of the existing backups.
--delete-expiredDeletes backups that do not conform to the retention policy defined in the
pg_probackup.confconfiguration file.--merge-expiredMerges the oldest incremental backup that satisfies the requirements of retention policy with its parent backups that have already expired.
--dry-runDisplays the current status of all the available backups, without deleting or merging expired backups, if any.
Pinning Options
You can use these options together with backup and set-backup commands.
For details on backup pinning, see the section Backup Pinning.
--ttl=ttlSpecifies the amount of time the backup should be pinned. Must be a non-negative integer. The zero value unpins the already pinned backup. Supported units: ms, s, min, h, d (s by default).
Example:
--ttl=30d--expire-time=timeSpecifies the timestamp up to which the backup will stay pinned. Must be an ISO-8601 complaint timestamp. If the time zone offset is not specified, the local time zone is used.
Example:
--expire-time="2020-01-01 00:00:00+03"
Logging Options
You can use these options with any command.
--no-colorDisable coloring for console log messages of
warninganderrorlevels.--log-level-console=log_levelControls which message levels are sent to the console log. Valid values are
verbose,log,info,warning,errorandoff. Each level includes all the levels that follow it. The later the level, the fewer messages are sent. Theofflevel disables console logging.Default:
infoNote
All console log messages are going to stderr, so the output of show and show-config commands does not mingle with log messages.
--log-level-file=log_levelControls which message levels are sent to a log file. Valid values are
verbose,log,info,warning,error, andoff. Each level includes all the levels that follow it. The later the level, the fewer messages are sent. Theofflevel disables file logging.Default:
off--log-filename=log_filenameDefines the filenames of the created log files. The filenames are treated as a
strftimepattern, so you can use %-escapes to specify time-varying filenames.Default:
pg_probackup.logFor example, if you specify the
pg_probackup-%u.logpattern, pg_probackup generates a separate log file for each day of the week, with%ureplaced by the corresponding decimal number:pg_probackup-1.logfor Monday,pg_probackup-2.logfor Tuesday, and so on.This option takes effect if file logging is enabled by the
--log-level-fileoption.--error-log-filename=error_log_filenameDefines the filenames of log files for error messages only. The filenames are treated as a
strftimepattern, so you can use %-escapes to specify time-varying filenames.Default: none
For example, if you specify the
error-pg_probackup-%u.logpattern, pg_probackup generates a separate log file for each day of the week, with%ureplaced by the corresponding decimal number:error-pg_probackup-1.logfor Monday,error-pg_probackup-2.logfor Tuesday, and so on.This option is useful for troubleshooting and monitoring.
--log-directory=log_directoryDefines the directory in which log files will be created. You must specify the absolute path. This directory is created lazily, when the first log message is written.
Default:
$BACKUP_PATH/log/--log-format-console=log_formatDefines the format of the console log. Only set from the command line. Note that you cannot specify this option in the
pg_probackup.confconfiguration file through the set-config command and that the backup command also treats this option specified in the configuration file as an error. Possible values are:plain— sets the plain-text format of the console log.json— sets the JSON format of the console log.
Default:
plain--log-format-file=log_formatDefines the format of log files used. Possible values are:
plain— sets the plain-text format of log files.json— sets the JSON format of log files.
Default:
plain--log-rotation-size=log_rotation_sizeMaximum size of an individual log file. If this value is reached, the log file is rotated once a pg_probackup command is launched, except
helpandversioncommands. The zero value disables size-based rotation. Supported units: kB, MB, GB, TB (kB by default).Default:
0--log-rotation-age=log_rotation_ageMaximum lifetime of an individual log file. If this value is reached, the log file is rotated once a pg_probackup command is launched, except
helpandversioncommands. The time of the last log file creation is stored in$BACKUP_PATH/log/log_rotation. The zero value disables time-based rotation. Supported units: ms, s, min, h, d (min by default).Default:
0
Connection Options
You can use these options together with backup, catchup, and checkdb commands.
All libpq environment variables are supported.
-ddbname--pgdatabase=dbnamePGDATABASESpecifies the name of the database to connect to. The connection is used only for managing backup process, so you can connect to any existing database. If this option is not provided on the command line,
PGDATABASEenvironment variable, or thepg_probackup.confconfiguration file, pg_probackup tries to take this value from thePGUSERenvironment variable, or from the current user name ifPGUSERvariable is not set.-hhost--pghost=hostPGHOSTSpecifies the host name of the system on which the server is running. If the value begins with a slash, it is used as a directory for the Unix domain socket.
Default:
localhost-pport--pgport=portPGPORTSpecifies the TCP port or the local Unix domain socket file extension on which the server is listening for connections.
Default:
5432-Uusername--pguser=usernamePGUSERUser name to connect as.
-w--no-passwordDisables a password prompt. If the server requires password authentication and a password is not available by other means such as a .pgpass file or
PGPASSWORDenvironment variable, the connection attempt will fail. This flag can be useful in batch jobs and scripts where no user is present to enter a password.-W--passwordForces a password prompt. (Deprecated)
Compression Options
You can use these options together with backup and archive-push commands.
--compress-algorithm=compression_algorithmDefines the algorithm to use for compressing data files. Possible values are
zlib,lz4,zstd,pglz, andnone. If set to any value, butnone, this option enables compression that uses the corresponding algorithm. Both data files and WAL files are compressed. By default, compression is disabled. For the archive-push command, thepglzcompression algorithm is not supported.Note
pg_probackup supports compression algorithms included in the Postgres Pro version. In particular:
lz4 is supported for Postgres Pro 14 and higher.
zstd is supported for Postgres Pro 15 and higher.
Default:
none--compress-level=compression_levelDefines the compression level. This option can be used together with the
--compress-algorithmoption. Possible values depend on the compression algorithm specified:0 — 9 for
zlib1 for
pglz0 — 12 for
lz40 — 22 for
zstd
The value of 0 sets the default compression level for the specified algorithm:
6 for
zlib1 for
pglz9 for
lz43 for
zstd
Note
The pure lz4 algorithmn has only one compression level — 1. So, if the specified compression algorithm is
lz4and--compress-levelis greater than 1, the lz4hc algorithm is actually used, which is much slower although does better compression.Default:
1--compressSpecifies the default compression algorithm and
--compress-level=1. The default algorithm is selected among those supported by Postgres Pro according to the priorities:zstd(highest) ->lz4->zlib->pglz. The--compressoption overrides the--compression-algorithmand--compress-levelsettings and cannot be specified together with them.
Archiving Options
These options can be used with the archive-push command in the archive_command setting and the archive-get command in the restore_command setting.
Additionally, remote mode options and logging options can be used.
--wal-file-path=wal_file_pathProvides the path to the WAL file in
archive_commandandrestore_command. Use the%pvariable as the value for this option or explicitly specify the path to a file outside of the data directory. If you skip this option, the path specified inpg_probackup.confwill be used.--wal-file-name=wal_file_nameProvides the name of the WAL file in
archive_commandandrestore_command. Use the%fvariable as the value for this option for correct processing. If the value of--wal-file-pathis a path outside of the data directory, explicitly specify the filename.--overwriteOverwrites archived WAL file. Use this flag together with the archive-push command if the specified subdirectory of the backup catalog already contains this WAL file and it needs to be replaced with its newer copy. Otherwise,
archive-pushreports that a WAL segment already exists, and aborts the operation. If the file to replace has not changed,archive-pushskips this file regardless of the--overwriteflag.--batch-size=batch_sizeUsed to speed up archiving in case of
archive-pushor to speed up recovery in case ofarchive-get. Sets the maximum number of WAL files that can be copied into the archive by a singlearchive-pushprocess, or from the archive by a singlearchive-getprocess.--archive-timeout=wait_timeSets the timeout for considering existing
.partfiles to be stale. By default, pg_probackup waits 300 seconds. This option can be used only with archive-push command.--no-ready-renameDo not rename status files in the
archive_statusdirectory. This option should be used only ifarchive_commandcontains multiple commands. This option can be used only with archive-push command.--no-syncDo not sync copied WAL files to disk. You can use this flag to speed up archiving process. Using this flag can result in WAL archive corruption in case of operating system or hardware crash. This option can be used only with archive-push command.
--prefetch-dir=pathDirectory used to store prefetched WAL segments if
--batch-sizeoption is used. Directory must be located on the same filesystem and on the same mountpoint thePGDATA/pg_walis located. By default files are stored inPGDATA/pg_wal/pbk_prefetchdirectory. This option can be used only with archive-get command.--no-validate-walDo not validate prefetched WAL file before using it. Use this option if you want to increase the speed of recovery. This option can be used only with archive-get command.
Remote Mode Options
This section describes the options related to running pg_probackup operations remotely via SSH. These options can be used with add-instance, set-config, backup, catchup, restore, archive-push, and archive-get commands.
For details on configuring and using the remote mode, see the section called “Configuring the Remote Mode” and the section called “Using pg_probackup in the Remote Mode”.
--remote-proto=protoSpecifies the protocol to use for remote operations. Currently only the SSH protocol is supported. Possible values are:
sshenables the remote mode via SSH. This is the default value.noneexplicitly disables the remote mode.
You can omit this option if the
--remote-hostoption is specified.--remote-host=destinationSpecifies the remote host IP address or hostname to connect to.
--remote-port=portSpecifies the remote host port to connect to.
Default:
22--remote-user=usernameSpecifies remote host user for SSH connection. If you omit this option, the current user initiating the SSH connection is used.
--remote-path=pathSpecifies pg_probackup installation directory on the remote system.
--ssh-options=ssh_optionsProvides a string of SSH command-line options. For example, the following options can be used to set
keep-alivefor SSH connections opened by pg_probackup:--ssh-options="-o ServerAliveCountMax=5 -o ServerAliveInterval=60". For the full list of possible options, see ssh_config manual page.
Remote WAL Archive Options
This section describes the options used to provide the arguments for remote mode options in archive-get used in the restore_command command when restoring ARCHIVE backups or performing PITR.
--archive-host=destinationProvides the argument for the
--remote-hostoption in thearchive-getcommand.--archive-port=portProvides the argument for the
--remote-portoption in thearchive-getcommand.Default:
22--archive-user=usernameProvides the argument for the
--remote-useroption in thearchive-getcommand. If you omit this option, the user that has started the Postgres Pro cluster is used.Default: Postgres Pro user
Incremental Restore Options
This section describes the options for incremental cluster restore. These options can be used with the restore command.
-Iincremental_mode--incremental-mode=incremental_modeSpecifies the incremental mode to be used. Possible values are:
CHECKSUM— replace only pages with mismatched checksum and LSN.LSN— replace only pages with LSN greater than point of divergence.NONE— regular restore.
Partial Restore Options
This section describes the options for partial cluster restore. These options can be used with the restore command.
--db-exclude=dbnameSpecifies the name of the database to exclude from restore. All other databases in the cluster will be restored as usual, including
template0andtemplate1. This option can be specified multiple times for multiple databases.--db-include=dbnameSpecifies the name of the database to restore from a backup. All other databases in the cluster will not be restored, with the exception of
template0andtemplate1. This option can be specified multiple times for multiple databases.
Testing and Debugging Options
This section describes options useful only in a test or development environment.
PGPROBACKUP_TESTS_SKIP_HIDDENInstructs pg_probackup to ignore backups marked as hidden. Note that pg_probackup can never mark a backup as hidden. It can only be done by directly editing the
backup.controlfile. This option can only be set with environment variables.--destroy-all-other-dbsBy default, pg_probackup exits with an error if an attempt is made to perform a partial incremental restore since this destroys databases not included in the restore set. This flag allows you to suppress the error and proceed with the partial incremental restore (e.g., to keep a development database snapshot up-to-date with a production one). This option can be used with the restore command.
Important
Never use this flag in a production cluster.
PGPROBACKUP_TESTS_SKIP_EMPTY_COMMITInstructs pg_probackup to skip empty commits after pg_backup_stop.
Versioning
pg_probackup follows semantic versioning.
Authors
Postgres Professional, Moscow, Russia.
Credits
pg_probackup utility is based on pg_arman, which was originally written by NTT and then developed and maintained by Michael Paquier.