> >> het volgende geschreven: > >>> I included 5 databases that we used for testing in this link: > http://wikisend.com/download/570088/test_databases.zip > >>> > >>> The query performed on these databases is: > >>> delete from A where id=1; > >> > >> I could not resist trying this but the tables in the databases > >> appear all empty and I get neglectible timings. Do I need to run an > >> insert script first? > > > > No, it is all about preparing, so there is no need to insert data. > > When we perform the query "delete from A where id=1;" on the > > databases from the zip file, we get the following timings: > > > > 500 tables - 10 msec in total > > 1000 tables - 25 msec in total > > 5000 tables - 298 msec in total > > 10000 tables - 985 msec in total > > > > What we would indeed expect is to have neglectible timings. Perhaps > > our interpretation of neglectible differs? Could you please tell me > > what your timing is on the 10000 tables database? > > > > We used the .timer ON command in the SQLite command shell utility as > > well as timing from our own application that has SQLite integrated.
The vdbe program is 20 times larger for 10000 tables versus 500 tables (400K instructions for the later -vs- 20K for the former), and this appears to be where the time is spent -- generating all the foreign key checking and trigger code. Perhaps the memory allocator has issues when building such a huge vdbe set (I haven't looked at the code, but is it perchance doing a lot of realloc's as more triggers are added?) _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
