Ok, they are two individual ways to vacuum the db file size. Thanks. On Sat, Sep 2, 2017 at 1:17 AM, Darko Volaric <[email protected]> wrote:
> Maybe you misunderstood that sentence: "auto_vacuum=FULL" mode will > reduce the file size but so will a "VACUUM" command, independent of the > auto_vacuum setting. It makes that crystal clear by detailing how it works > later on that page: > > > The VACUUM command works by copying the contents of the database into a > temporary database file and then overwriting the original with the contents > of the temporary file. > > > So it will by definition use the minimum possible amount of space for the > resulting database file. > > > > > On Sep 1, 2017, at 6:53 PM, Jacky Lam <[email protected]> wrote: > > > > What I am understood from the answer is explicit code must be used during > > creating db, for example, auto_vacuum=FULL. > > If no, the file size will not reduce even deleting a number of records > and > > this is normal. > > > > > > On Sat, Sep 2, 2017 at 12:47 AM, Stephen Chrzanowski < > [email protected]> > > 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 <[email protected]> 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 <[email protected]> > >>> wrote: > >>> > >>>> > >>>> > >>>> On 9 Aug 2017, at 3:31am, Jacky Lam <[email protected]> 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/ > >>> mutex_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 > >>>> [email protected] > >>>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > >>>> > >>> _______________________________________________ > >>> sqlite-users mailing list > >>> [email protected] > >>> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > >>> > >> _______________________________________________ > >> sqlite-users mailing list > >> [email protected] > >> http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > >> > > _______________________________________________ > > sqlite-users mailing list > > [email protected] > > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > > _______________________________________________ > sqlite-users mailing list > [email protected] > http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list [email protected] http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
