On 28 Dec 2015, at 10:13am, Simon Slavin <slavins at bigfraud.org> wrote:
> Well I have a 43 Gigabyte database at work. I bet it doesn't take more than > a few hours to check. But I can't do it from home so it'll have to wait > until I get back to work next week for me to test that theory. Got back to work today and tried it. The database is actually 38.4 gigabytes at the moment. Almost all that space is taken up by one thin table with 713,099,083 (713 million) rows. I restored a server backup to the hard disk of my office computer and ran VACUUM on it. Run Time: real 12206.707 user 1219.335537 sys 514.479783 That's 3 hours 23 minutes. For a 38 Gigabyte database including a table with half a billion rows. Details: Running in the SQLite 3.8.5 shell tool on a four year old iMac with a spinning rust storage system. VACUUM was running in the background while I was doing light work (editing web pages, a bit of email, etc.) in the foreground. So you can criticise how VACUUM works if you like, but on a cheap old iMac, working in the background, it can still get through a big database in just a few hours. Simon.
