Hi Jay, Definitely worth investigating. Thanks for the tip!
-- Tito On 9 Nov 2008, at 8:44 AM, Jay A. Kreibich wrote: > On Sat, Nov 08, 2008 at 03:34:29PM -0800, Tito Ciuro scratched on > the wall: >> Hello, >> >> If I open a SQLite database in memory (using :memory:), would it be >> possible to save it on disk? Here's the reason: > >> Manipulating data in memory is ~3.4x faster than using the file >> system >> (YMMV). If I could process the bulk of the data in RAM, then I could >> save the final database on disk saving precious time. > > > Another option is to use an on-disk database, but turn off most of > the safety and security features. > > -- Turn the page cache up so it is large enough to hold the whole > database in the cache. > > -- Turn the journal file off. > > -- Turn synchronous off. > > (See http://sqlite.org/pragma.html for how to do all that) > > There will be some start-up cost as the database is pulled into the > cache, and it won't be quite as fast as a true :memory: database, > since it still writes out data into the OS file-cache buffers. > Overall your performance will be very similar to a fully in-memory > database, plus you won't have to deal with shuffling data back and > forth between a memory database and a disk database. > > Of course, you get most of that performance by turning off most > of the safety and security features so the reliability of a database > in this mode is more or less the same as an in-memory database... > the database is very likely to get corrupt if you suffer a process or > system failure. > > But it is faster. And sometimes that's what counts. > > -j > > -- > Jay A. Kreibich < J A Y @ K R E I B I.C H > > > "Our opponent is an alien starship packed with atomic bombs. We have > a protractor." "I'll go home and see if I can scrounge up a ruler > and a piece of string." --from Anathem by Neal Stephenson > _______________________________________________ > sqlite-users mailing list > sqlite-users@sqlite.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
