I run in iOS. The mmap is enable in recent version. So, once a mmap enable, data may lost after os crash unless msync. But I can’t find anywhere in the source of SQLite call the msync. Is it a bug?
原始邮件 发件人:Dan [email protected] 收件人:[email protected] 发送时间:2016年11月3日(周四) 17:38 主题:Re: [sqlite] Is msync necessary for SQLite? On 11/03/2016 02:13 PM, sanhua.zh wrote: I notice that SQLite may not call msync for mmap. Instead, it calls the fsync. As my search, fsync does not imply the msync. See this,https://groups.google.com/forum/#!topic/comp.unix.programmer/pIiaQ6CUKjU So, is it necessary call a msync for SQLite? Probably not in the default configuration, at any rate. SQLite mmap-mode only works if the system has a unified page-cache. Which is why it is disabled on some platforms (OpenBSD and others IIRC). Also, unless SQLITE_MMAP_READWRITE is defined at compile time, SQLite uses write() calls to modify to the db file, even though it reads the file by memory mapping it. Dan. _______________________________________________ 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
