On 16 Aug 2016, at 1:46pm, Dominique Devienne <ddevie...@gmail.com> wrote:
> On Tue, Aug 16, 2016 at 2:29 PM, Simon Slavin <slav...@bigfraud.org> wrote: > >> VACUUM destroys tables (and indexes) and makes new ones, so it frees pages >> and allocates new ones. The content of the 'unused' bytes in the >> newly-allocated pages would not have anything to do with the content of the >> pages which used to exist. I don't know if those bytes would dependably >> contain zero or just gibberish. >> > > That's one way to look at it. Another (mine) is that is "moves" pages and > "fills holes", My understanding is that for each table (and all the indexes on that table) VACUUM creates a new copy by reading the rows, not the pages) then deletes the old copy. In other words there's a brief instant when both copies exist. This would contrast with the idea that VACUUM intelligently moves data from page to page to use the free space. I don't think that's how VACUUM works. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
