Update to default compression algorithm for Heroku Postgres WAL compression

Change effective on 12 November 2026

We changed the default compression algorithm for the Heroku Data Labs WAL compression feature. The new algorithms are more performant for WAL compression. The default compression algorithm depends on the Heroku Postgres plan:

  • Heroku Postgres databases on -5 and higher plans use ztsd.
  • Heroku Postgres databases on -4 and lower plans use lz4.

For more information, see Heroku Data Labs: WAL Compression for Postgres Add-ons.