Thank you Pete for that clarification. Jérôme
Le 7 mars 2012 à 17:37, Pete a écrit : > I emailed sqlitemanager support re the manage/sql tab performance > difference. Mystery solved by the reply: > > "In the Manage panel when you see SELECT * FROM table the real query > executed is SELECT rowid FROM table and then a SELECT * FROM table WHERE > rowid=N is execute for each visible row of the listbox. In the SQL panel > query executed is just what you type" > On Mar 6, 2012 5:47 PM, "Pete" <p...@mollysrevenge.com> wrote: > >> I just noticed that the same vendor that makes SQLiteManager also makes an >> SQLite server package (cubeSQL) that does implement MVCC. But you're >> right, it's definitely not there in standard SQLite. An SQLite server >> sounds interesting though. >> Pete >> >> On Tue, Mar 6, 2012 at 11:35 AM, Bernard Devlin <bdrun...@gmail.com>wrote: >> >>> I notice from things discussed on the Valentina list that they >>> recommend using API methods rather than SQL calls, because the former >>> will be faster due to less overhead. So these different ways of >>> interacting with a sqlite database might well represent an application >>> using the sqlite API. >>> >>> Although when I use the Valentina VStudio SQL interface I will still >>> see results being returned in 25 ms, compared to 500 ms going through >>> sql yoga > revdb > v4rev sql > valentina. This is doing a "select *" >>> from a table with 22k rows (10mb in size). That's not to say that I'm >>> outraged at 500ms. There are other steps one can take to make an >>> interface responsive at these timescales. >>> >>> The Valentina guys are pretty used to comparing Livecode with the >>> other platforms for which they provide Valentina. On 19/12/2010 >>> Ruslan had this to say about Livecode: >>> >>> "REALbasic - as I remember -- was very fast, near to C code...so it >>> gives e.g. 5% overhead to pure C engine... Revolution and Director >>> give me x4-x10 overhead I think....Revolution because all params are >>> packed to strings ... Director because quite complex SDK similar to MS >>> COM ..." This conclusion by Ruslan appears to be only in the >>> discussion of calling the Valentina API, therefore one would expect >>> that adding other layers (sql, revdb, etc.) one would see other layers >>> adding their own torpor to the action. >>> >>> Does using explict transation control make any difference with sqlite? >>> It shouldn't matter in a case where the data is only being read. I >>> know on MVCC databases this is still a factor if one has a cursor >>> containing the read data, as such data might still be altered from the >>> cursor and the currency control of the MVCC requires a handle on such >>> data to be able to maintain consistency. I can't see that it would >>> apply to sqlite, and this site confirms that sqlite does not implement >>> MVCC: http://www.sqliteconcepts.org/SI_index.html >>> >>> Bernard >>> >>> On Tue, Mar 6, 2012 at 5:15 PM, Pete <p...@mollysrevenge.com> wrote: >>>> I got the same results on the movies database and even more pronounced >>>> differences on a table in one of my own databases with ~48k records in >>> it: >>>> SQL tab 0.519secs, Manage tab 0.045 secs, more than a 10-fold >>> difference! >>>> Just a straight SELECT * in each case. >>>> Pete >>> >>> _______________________________________________ >>> use-livecode mailing list >>> use-livecode@lists.runrev.com >>> Please visit this url to subscribe, unsubscribe and manage your >>> subscription preferences: >>> http://lists.runrev.com/mailman/listinfo/use-livecode >>> >>> >> >> >> -- >> Pete >> Molly's Revenge <http://www.mollysrevenge.com> >> >> >> > _______________________________________________ > use-livecode mailing list > use-livecode@lists.runrev.com > Please visit this url to subscribe, unsubscribe and manage your subscription > preferences: > http://lists.runrev.com/mailman/listinfo/use-livecode _______________________________________________ use-livecode mailing list use-livecode@lists.runrev.com Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-livecode
