The 179148 failures on 'access' system call is due to access check of two files - the journal file and the wal-file. The journal mode was OFF as also WAL mode. Why is sqlite checking access permissions for this file 179140 times? Removing or optimising this will make it faster by 20% atleast!
access("/dev/shm/test.db-journal", F_OK) = -1 ENOENT (No such file or directory) access("/dev/shm/test.db-wal", F_OK) = -1 ENOENT (No such file or directory) -Sreekumar On Wed, Aug 10, 2011 at 5:28 PM, Sreekumar TP <sreekumar...@gmail.com>wrote: > Hi, > > I have the results from the tests (below). Alot of the time is spent in > checking file permissions and locking the file (40 %). > > > Inmem > > % time seconds usecs/call calls errors syscall > > ------ ----------- ----------- --------- --------- ---------------- > > 28.53 0.124727 1 118524 write > > 23.42 0.102382 0 414624 gettimeofday > > 20.78 0.090840 1 76513 read > > 13.72 0.059977 0 191255 _llseek > > > > Db in tmpfs > > % time seconds usecs/call calls errors syscall > > ------ ----------- ----------- --------- --------- ---------------- > > 21.83 0.257073 1 263306 write > > 21.18 0.249488 1 179148 179148 access > > 20.61 0.242725 0 509292 fcntl64 > > 13.04 0.153551 0 448720 _llseek > > 9.44 0.111194 1 189370 read > > 8.16 0.096124 0 414624 gettimeofday > 2.55 0.030000 3750 8 fdatasync > > On Tue, Aug 9, 2011 at 7:34 PM, Pavel Ivanov <paiva...@gmail.com> wrote: > >> > Journal mode is WAL >> >> I believe in-memory database can't have journal mode WAL. So you >> compare completely different settings. >> >> >> Pavel >> >> >> On Tue, Aug 9, 2011 at 5:15 AM, <sreekumar...@gmail.com> wrote: >> > >> > Journal mode is WAL >> > >> > >> > ------Original Message------ >> > From: Roger Binns >> > Sender: sqlite-users-boun...@sqlite.org >> > To: General Discussion of SQLite Database >> > ReplyTo: General Discussion of SQLite Database >> > Subject: Re: [sqlite] In memory v/s tmpfs >> > Sent: Aug 9, 2011 2:42 PM >> > >> > -----BEGIN PGP SIGNED MESSAGE----- >> > Hash: SHA1 >> > >> > On 08/08/2011 06:34 PM, sreekumar...@gmail.com wrote: >> >> From the point of view of performance, I expected similar performance , >> tmpfs being a little slower due to filesystem overhead. However, the >> operations on tmpfs was much slower than expected. >> > >> > Using tmpfs requires many kernel calls which is considerably more effort >> > than the occasional malloc call. Additionally files have to be locked, >> > journals made etc (you didn't mention your journal setting). >> > >> > Roger >> > -----BEGIN PGP SIGNATURE----- >> > Version: GnuPG v1.4.11 (GNU/Linux) >> > Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ >> > >> > iEYEARECAAYFAk5A+g0ACgkQmOOfHg372QTR8ACgqNeeuOxHRy7+hMH5RY/OAyV2 >> > Wq0AoMaSRtoFN4obCgmgHlpHthd9z5Zp >> > =pkJt >> > -----END PGP SIGNATURE----- >> > _______________________________________________ >> > sqlite-users mailing list >> > sqlite-users@sqlite.org >> > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >> > >> > >> > Sent from BlackBerry® on Airtel >> > _______________________________________________ >> > 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