> Because my concern is this, I don't know how SQLite will do > > Delete from table where col not in (select from large temp dataset) > > How the delete will actually be walked, if it will create a serverside > cursor and walk the values in the in statement then it will > be fine and > fast, > If however it loads all the values into memory and then walk > the dataset > it would require a large amount of memory,
I believe that it will write the results of the subquery to a temporary table, so I doubt that memory usage will be a problem. I'm only about 98% sure though, so no guarantees. :) EXPLAIN will tell you for sure though. > Your suggestion to drop the table and recreate from temp > although a good > idea will probably modify the database which means that if I version > control it, it will create a large amount of changes each > time an import > is run, even though nothing might have been changed. I think you have issues here either way though - one way or another you need to know that nothing changed. You may be able to determine that for free, depending on your approach, or you may need to go out of your way to determine that, it depends on your approach. But I wouldn't assume that you can know this for free and that any solution that requires work to know that is inherently bad. -Tom ----------------------------------------------------------------------------- To unsubscribe, send email to [EMAIL PROTECTED] -----------------------------------------------------------------------------
