I have never seen such a dramatic difference in non-sqlite3 operations. For example, cat has some difference but is ~13%.
$ time cat file.sqa > /dev/null real 0m7.282s user 0m0.067s sys 0m2.371s $ time cat file.sqa > /dev/null real 0m6.316s user 0m0.062s sys 0m2.319s How to prove the large time difference of sqlite3 is indeed due to cache and where is the cache? Why the caching used by sqlite3 can not persist for a longer time? On Sat, Oct 19, 2019 at 7:29 PM Keith Medcalf <kmedc...@dessus.com> wrote: > > > On Saturday, 19 October, 2019 18:05, Peng Yu <pengyu...@gmail.com> wrote: > > Looks like the difference between reading from disk and reading from cache. > > >I see that sqlite3 can be very different in terms of run time. > > >$ time sqlite3 file.sqa -Atv > /dev/null > > > >real 0m3.259s > >user 0m0.193s > >sys 0m0.704s > >$ time sqlite3 file.sqa -Atv > /dev/null > > > >real 0m0.148s > >user 0m0.086s > >sys 0m0.057s > > > ># Then do some else briefly > > > >$ time sqlite3 file.sqa -Atv > /dev/null > > > >real 0m3.853s > >user 0m0.200s > >sys 0m0.828s > > > >$ time sqlite3 gncdhgncsym2htmlsqa.sqa -Atv > /dev/null > > > >real 0m0.172s > >user 0m0.094s > >sys 0m0.065s > > > >file.sqa is of size 4.1G and 42282 rows. > > > >Does anybody know why there can be such big differences in speed? > > > >My testing machine is a MacbookAir. > > > > -- > The fact that there's a Highway to Hell but only a Stairway to Heaven says a > lot about anticipated traffic volume. > > > > _______________________________________________ > sqlite-users mailing list > sqlite-users@mailinglists.sqlite.org > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users -- Regards, Peng _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
