FYI, this overrides what you configure as your connection string in your applications service configuration, so probably should remove it.

Unless I'm mistaken somehow, this is the connection string that will be used at design time while developing only (to run migrations). In your own app, this whole class should never be used. That's supposedly what IDesignTimeDbContextFactory does. Can you explain why you think this will override that in the app?

postgres didn't like this field syntax. seems to need everything fully qualified with schema. this worked for me:

return $@"
DELETE
FROM ""{schema}"".""{table}""
WHERE ""{schema}"".""{table}"".""ExpiresAt"" < @now
AND ctid IN (
    SELECT ctid
    FROM  ""{schema}"".""{table}""
    ORDER BY ""{schema}"".""{table}"".""ExpiresAt""
    LIMIT @count
)";

Thanks. I have little experience with postgres, and not enough time to test things out (which is why this PR is still pending).

With little simplification, I'd guess this should also work:

return $@"
DELETE
FROM ""{schema}"".""{table}""
WHERE ""ExpiresAt"" < @now
AND ctid IN (
    SELECT ctid
    FROM  ""{schema}"".""{table}""
    ORDER BY ""ExpiresAt""
    LIMIT @count
)";

The problem is with the LIMIT not being accepted without using CTID, I think.