err.. Clarification... It can be set to automatically vacuum the database on connection close when setting a particular pragma.
On Fri, Sep 1, 2017 at 12:47 PM, Stephen Chrzanowski <pontia...@gmail.com> wrote: > You'll want to vacuum the database. > > https://sqlite.org/lang_vacuum.html > > Deleting records from a SQLite database only changes the pages that > already exist within the file. It doesn't prune anything automatically. > It can do so, though, if you set the appropriate pragma. > > On Fri, Sep 1, 2017 at 12:41 PM, Jacky Lam <jacky...@gmail.com> wrote: > >> Hi All, >> While using my own implemented file system, the db file size will only >> expand and not prune even remove record from the db. >> Could anyone advise me that what I am missing in order to pruning the db >> size when removing a number of records? >> Jacky >> >> On Wed, Aug 9, 2017 at 11:02 AM, Simon Slavin <slav...@bigfraud.org> >> wrote: >> >> > >> > >> > On 9 Aug 2017, at 3:31am, Jacky Lam <jacky...@gmail.com> wrote: >> > >> > > 1. Can I call sqlite3_open more than one times before calling >> > sqlite3_close >> > > and sqlite3_free? >> > >> > Call sqlite3_open() for each database you want to open. You can have >> any >> > number of databases open at the same time. Call sqlite3_close() for >> each >> > database you have open when you no longer need it. After closing the >> last >> > connection call sqlite3_shutdown() as described in >> > >> > <https://sqlite.org/c3ref/initialize.html> >> > >> > (The above ignores use of SQL's ATTACH command.) >> > >> > You are not expected to ever call sqlite3_free() unless you are using >> > SQLite to do other memory-handing tasks for you. Most people who use >> > SQLite never call sqlite3_free(). >> > >> > > 2. If the above mentioned devices change to mutli-thread setting but >> no >> > > thread safe functions such as mutex, is this setting still fine? >> > >> > You have explicitly declared SQLITE_THREADSAFE=0 . That means you will >> > arrange that only one thread will be doing SQLite calls at once. As >> long >> > as you can ensure this, SQLite will function correctly. >> > >> > > If not, how can I make it thread safe with lack of mutex support >> in >> > > the system? >> > >> > Do any of the following: >> > >> > A) Implement your own mutex system. >> > >> > B) Use SQLite’s mutex system ( <https://sqlite.org/c3ref/mute >> x_alloc.html> >> > ) >> > >> > C) Supply the value SQLITE_OPEN_FULLMUTEX when you open connections >> using >> > sqlite3_open_v2(), as described in <https://sqlite.org/c3ref/open.html> >> . >> > >> > Please note that the above is a top-of-the-head answer and I have not >> > personally tries each of the options to make sure it works. >> > >> > Simon. >> > _______________________________________________ >> > sqlite-users mailing list >> > sqlite-users@mailinglists.sqlite.org >> > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> > >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@mailinglists.sqlite.org >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users >> > > _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
