Out of memory errors when using AWS S3 SDFS backend

Detail name	Value
Changelog Number	26571
Type	Bug
Status	Resolved
Affected Versions	Exasol 7.1.0, Exasol 8.0.0
Fix Versions	Exasol 2025.1.3, Exasol 2025.2.0
Resolution Date	2025-09-17

Description

The AWS S3 SDFS backend for remote volumes can allocate an unbounded amount of memory. This can lead to “out of memory” errors during backups (both writing and restoring) and eventually to DB crashes.

The issue only affects creating backups on S3 and S3 compatible remote volumes.

The affected backend is the default in database version 8 and is activated on-demand in version 7.1 via remote volume option cloud_backend_v2.

Workaround

Version 8: add option cloud_backend_v1 to the remote volume.

Version 7.1: remove option cloud_backend_v2 from the remote volume.

Fix

The AWS S3 SDFS backup backend uses a limited amount of memory.