The Linux kernel used to default to writeback for a while until 2.6.36 where it then defaulted to ordered. So you're seeing the ordered behavior now which is the safest mode. http://forum.linode.com/viewtopic.php?t=7815
How to convert to writeback if that's what you want...it is a more dangerous option. http://ubuntuforums.org/showthread.php?t=107856 Michael D. Black Senior Scientist Advanced Analytics Directorate Advanced GEOINT Solutions Operating Unit Northrop Grumman Information Systems ________________________________________ From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on behalf of Kevin Liao [kevin...@gmail.com] Sent: Thursday, November 29, 2012 11:47 AM To: sqlite-users@sqlite.org Subject: EXT :[sqlite] Sqlite 3.4.1 write performance difference between linux kernel 2.6.33 and 3.4.6 I have a simple propram that issues sqlite update command every few seconds. The platform is linux based with kernel 2.6.33 and sqlite version is 3.4.1. The db file is on the partition with EXT3 format. Usually it takes only 11-13 ms to execute the update commands. Recently I upgrade the kernel to 3.4.6 but find one problem. It takes about 43-51 ms to finish the update command now. That is, the write performance is almost four times slower that kernel 2.6.33. The following is source code of the function I used for updating sqlite. Is there anything I do wrong or does anyone have the similar problem? Thanks a lot. int my_db_update_progress(int value) { sqlite3* db; char* zSQL = NULL; int ret = 0; int changed = 0; zSQL = sqlite3_mprintf("UPDATE MY_TASK SET progress = %d WHERE \ task_pid = %d;", value, getpid()); ret = sqlite3_open("/etc/mydb.db", &db); if (ret) { sqlite3_free(zSQL); return -1; } sqlite3_busy_timeout(db, 20000); ret = sqlite3_exec(db, zSQL, NULL, NULL, NULL); if (sqlite3_total_changes(db)) changed = 1; sqlite3_close(db); sqlite3_free(zSQL); if (ret != SQLITE_OK || !changed) return -1; return 0; } Regards, Kevin _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
