# Treat pg_basebackup throttling and WAL streaming as separate budgets

> Budget data-copy traffic and streamed WAL separately when throttling a PostgreSQL base backup.

- Canonical URL: https://update.dsesecurity.com/updates/treat-pg-basebackup-throttling-and-wal-streaming-as-separate-budgets/
- Publisher: Detection Systems & Engineering (DSE Security)
- Author: DSE Security Editorial Team
- Published: 2026-10-15T13:32:27+00:00
- Modified: 2026-10-15T13:36:15+00:00
- Last reviewed by DSE: 2026-10-15
- Resource type: Guide
- DSE priority: Information
- Topics: Business Continuity, IT
- Reading time: 2 minutes

## What you need to know

Budget data-copy traffic and streamed WAL separately when throttling a PostgreSQL base backup.

## Potentially affected

This guidance applies to PostgreSQL 17 pg_basebackup planning, particularly streamed-WAL backups. It does not prescribe a transfer rate or infer available replication capacity for a particular server.

## DSE recommendation

DSE recommends putting data transfer, WAL generation, replication connections, and destination capacity into the same change worksheet.

## Article

Budget data-copy traffic and streamed WAL separately when throttling a PostgreSQL base backup.

## Source facts

In PostgreSQL 17, pg_basebackup can stream WAL alongside the base backup using its stream collection method. That opens a second replication connection, so the run needs two replication connections rather than one. The max-rate setting limits data-directory transfer, but it limits WAL transfer only when the collection method is fetch. Consequently, setting a base-backup rate cap does not also cap the separate streamed WAL traffic. An incremental backup also requires combination with its prerequisite backups before use.

Source: [PostgreSQL 17 — pg_basebackup](https://www.postgresql.org/docs/17/app-pgbasebackup.html).

## Applicability

This guidance applies to PostgreSQL 17 pg_basebackup planning, particularly streamed-WAL backups. It does not prescribe a transfer rate or infer available replication capacity for a particular server.

## DSE recommendation

DSE recommends putting data transfer, WAL generation, replication connections, and destination capacity into the same change worksheet. State explicitly which traffic the configured rate limit controls. Prefer a conservative trial during a supervised window before increasing throughput. Keep the selected WAL method and any incremental dependencies attached to the backup record, so recovery staff do not mistake an individual incremental directory for a self-contained recovery image.

## Verification

Use a test cluster to observe replication connections and data transfer with the intended WAL mode. Confirm that monitoring distinguishes data-copy throughput from WAL traffic. Reconstruct and start the resulting backup in isolation, including the combination stage if an incremental backup was selected.

## Official reference

[PostgreSQL 17 — pg_basebackup](https://www.postgresql.org/docs/17/app-pgbasebackup.html). Reviewed October 15, 2026.

## Primary reference

- Name: PostgreSQL 17 — pg_basebackup
- Authority: www.postgresql.org
- URL: https://www.postgresql.org/docs/17/app-pgbasebackup.html
- Source publication date: Not stated by the source

## Citation and use

Preferred citation: “Treat pg_basebackup throttling and WAL streaming as separate budgets,” DSE Security, https://update.dsesecurity.com/updates/treat-pg-basebackup-throttling-and-wal-streaming-as-separate-budgets/
Publishing principles: https://update.dsesecurity.com/updates/dse-updates-editorial-methodology/
Usage and citation policy: https://update.dsesecurity.com/usage/
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