1.3. pg_probackup3 Backup Data Source Modes #
The pg_probackup3 utility supports the following backup data source modes: BASE, DIRECT, and PRO. The chosen mode determines how the connection to the database server is established and how the files for creating the backup are obtained.
The table below provides a concise overview of the key differences between these backup data source modes.
| Backup Data Source Mode | Data Transfer Method | libpgprobackup Library Required | Validation | CFS Support | Additional Extensions Required |
|---|---|---|---|---|---|
| BASE | Via the pg_basebackup replication protocol | No | Yes | No | None |
| DIRECT | Direct filesystem access | No | Yes | Yes | PTRACK (for incremental backups) |
| PRO | Via the proprietary replication protocol | Yes | Yes | Yes | pgpro_bindump (for protocol implementation), PTRACK (for incremental backups) |
A detailed description of each mode is provided in the sections below.
1.3.1. BASE #
The BASE mode uses the standard pg_basebackup replication protocol. Data is copied without using advanced change-tracking and segmentation mechanisms.
Features:
Copies data via the replication protocol using the
libpqlibrary.Compatible with PostgreSQL and requires no additional extensions.
Limitations:
Requires access to system functions.
Does not support accelerated incremental mechanisms (PTRACK).
Generally slower for large data volumes compared to other modes.
1.3.2. DIRECT #
In the DIRECT mode, the pg_probackup3 utility gains direct access to the PGDATA directory via the filesystem, bypassing the replication protocol for file transfer.
Features:
Uses a standard database connection.
Performs data integrity checks during transfer.
Suitable for cases where access via the replication protocol is unavailable or undesirable.
Limitations:
Requires direct access to the server filesystem.
Requires access to system functions.
For remote servers, requires SSH-based filesystem access. SSH is not required for accessing
PGDATA.
1.3.3. PRO #
The PRO mode uses a dedicated library, which includes data processing logic, and its own backup protocol. This protocol is specifically designed for secure and fast data transfer from the server.
Features:
Connects to the database via the system
libpqlibrary.Transfers data via its own proprietary replication protocol.
Supports all backup types: FULL, DELTA, and PTRACK.
Optimized for performance and reduced server load.
Performs data integrity checks during transfer.
Limitations:
Requires the pgpro_bindump plugin to be installed on the server side.
Requires the
libpb3_encoder.solibrary to be installed on the server. No separate library is required for pg_probackup3.Can only be used with Postgres Pro.
Configuring continuous WAL archiving to a remote server requires an SSH connection (not required for STREAM mode).