A followup. Keeping it in this thread for some context.
The Linode host I’ve been running tt-rss/mysql on for years killed the export process after some number of hours. My thought was to move the mysql DB to a much beefier local box and do the migration from mysql to postgres there (and probably just leave it running on the local box).
So I installed your containers on the local box. I also added a mariadb container and modified the tt-rss config.php to point to that db, then I exported the DB on the Linode server (mysqldump -u root -p ttrss > ~/ttrss.sql), copied that to the local host, mounted that dir in the mariadb container, got a shell in that container, created the db and then imported the tables (mysql -u root -p ttrss < /mnt/ttrss.sql).
After I did that, tt-rss couldn’t see any articles in the new DB. So I exported opml from the original and imported it on the new one. That didn’t help. The data is in the DB tables but tt-rss must not be able to relate the feeds I imported via opml to the articles in the DB.
In one of my sql-level export/import experiments I did end up being able to see articles in the new db but many/most articles were marked read, unlike from the original DB.
Is there a better way to migrate the mysql DB to a new host, with the same set of feeds and article read/unread status?