So, it means that this is a bug in old version of SQLite ?
原始邮件 发件人:Dan kennedydanielk1...@gmail.com 收件人:sqlite-userssqlite-us...@mailinglists.sqlite.org 发送时间:2016年11月3日(周四) 18:38 主题:Re: [sqlite] Is msync necessary for SQLite? On 11/03/2016 04:53 PM, sanhua.zh wrote: Here is a part of code in [unixWrite]. (os_unix.h) Is not it written by mmap ? It changed to avoid writing via mmap for version 3.10.0. http://www.sqlite.org/src/info/67c5d3c646 And I don't think mmap() was used on IOS until 3.11.0. http://www.sqlite.org/src/info/e9a51d2a580daa0f Dan. #if SQLITE_MAX_MMAP_SIZE0 /* Deal with as much of this write request as possible by transfering ** data from the memory mapping using memcpy(). */ if( offsetpFile-mmapSize ){ if( offset+amt = pFile-mmapSize ){ int size = -1; struct stat buf; /* Used to hold return values of fstat() */ if( !osFstat(pFile-h, buf) ){ size = (int)buf.st_size; } memcpy(((u8 *)(pFile-pMapRegion))[offset], pBuf, amt); return SQLITE_OK; }else{ int nCopy = (int)(pFile-mmapSize - offset); memcpy(((u8 *)(pFile-pMapRegion))[offset], pBuf, nCopy); pBuf = ((u8 *)pBuf)[nCopy]; amt -= nCopy; offset += nCopy; } } #endif 原始邮件 发件人:Richard hipp...@sqlite.org 收件人:SQLite mailing listsqlite-us...@mailinglists.sqlite.org 发送时间:2016年11月3日(周四) 17:49 主题:Re: [sqlite] Is msync necessary for SQLite? On 11/3/16, sanhua.zh sanhua...@foxmail.com wrote: 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? No. Mmap() is only used for reading, not writing. All changes are implemented by calling write() and fsync(). -- D. Richard Hipp d...@sqlite.org _______________________________________________ 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 _______________________________________________ sqlite-users mailing list sqlite-users@mailinglists.sqlite.org http://mailinglists.sqlite.org/cgi-bin/mailman/listinfo/sqlite-users
