On 3 Feb 2011, at 12:45am, Jeff Rogers wrote: > Any idea why pg does ok on these queries without the extra index - > Maybe they're created by default?
Both PostgreSQL and SQLite will make indexes on the fly if that's the most efficient way of scanning the table. However, PostgreSQL can keep the index around and reuse it any number of times, at the expense of using up disk space and memory to store the index. SQLite is better designed for small light systems and has to place minimal load on disk space and memory, so it doesn't keep indexes around between uses. What it comes down to is that if you use SQLite you have to work out what indexes are worthwhile for yourself whereas Postgres does some of the work for you but takes up more memory and disk space to do so. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
