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/ > 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 > > 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
