When a user must shut down and restart in single-user mode to run vacuum on an entire database, that does a lot of work that's unnecessary for getting the system online again, even without index_cleanup. We had a recent case where a single-user vacuum took around 3 days to complete.
Now that we have a concept of a fail-safe vacuum, maybe it would be beneficial to skip a vacuum in single-user mode if the fail-safe criteria were not met at the beginning of vacuuming a relation. This is not without risk, of course, but it should be much faster than today and once up and running the admin would have a chance to get a handle on things. Thoughts? -- John Naylor EDB: http://www.enterprisedb.com
