Performance issue with large attachments in default storage in DB on HANA

[mofterdinger]

Hi, I did some tests with very large attachments and the default storage (DB / HANA) in cds-feature-attachments.

The test environment:

• Bookshop single-tenant application with cds-feature-attachments
• Using default storage for attachment content in DB
• Bookshop deployed to BTP using HANA as DB

The following performance issue are found:

• Uploading an attachment with about 3,5 GB content size takes 4:04 min from home location
• Saving the draft entity with an attachment of 3,5 GB content size takes about
• Switching a draft-enabled entity with an attachment of size 3,5 GB to edit mode takes about 5:30min. To avoid Gateway Timeouts the app-router needs to be configured with a larger timeout for backend calls.

Running bookshop locally with h2 in-memory via command line mvn spring-boot:run -Dspring-boot.run.jvmArguments="-Xms8048m -Xmx16096m":

• Upload: 4s
• Save draft: 2s
• Edit draft: 2s