On Tue, Sep 27, 2011 at 8:14 AM, Black, Michael (IS) <michael.bla...@ngc.com > wrote:
> > Richard almost got it. According to this link JFFS doesn't support > MMAP_SHARED. Can another flag be used? > No. The whole point of doing the mmap() is so that different processes accessing the same database file can share some memory in order to coordinate their activities. MMAP_SHARED is absolutely required in this context. If JFFS does not support MMAP_SHARED, then it won't support WAL. Except, if you only have a single process accessing the database file, then you can set "PRAGMA locking_mode=EXCLUSIVE" and the shared memory will not be used. > > http://lists.busybox.net/pipermail/uclibc/2006-November/016838.html > > Michael D. Black > Senior Scientist > NG Information Systems > Advanced Analytics Directorate > > > > > From: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on > behalf of Richard Hipp [d...@sqlite.org] > Sent: Monday, September 26, 2011 1:54 PM > To: General Discussion of SQLite Database > Subject: EXT :Re: [sqlite] Problem with using WAL journal mode in embedded > system (disk I/O error) > > > On Mon, Sep 26, 2011 at 2:48 PM, Korey Calmettes <kcalmet...@icontime.com > >wrote: > > > Richard, > > > > Thanks for the tip of recreating the experiment in a separate directory. > > However the same error occurs. > > > > sqlite> .tables > > (5386) os_unix.c:28414: (22) mmap(/data/test.db-shm) - > > (5386) statement aborts at 109: [SELECT name FROM sqlite_master WHERE > > type IN ('table','view') AND name NOT LIKE 'sqlite_%' UNION ALL SELECT > > name FROM sqlite_temp_master WHERE type IN ('table','view') ORDER BY 1] > > disk I/O error > > Error: disk I/O error > > sqlite> > > > > Any additional ideas why mmap would be failing? > > > > > Perhaps your kernel doesn't support mmap() on JFFS filesystems? (That's > just a guess.) > > > > > Korey > > > > -----Original Message----- > > From: sqlite-users-boun...@sqlite.org > > [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Richard Hipp > > Sent: September 26, 2011 11:36 AM > > To: General Discussion of SQLite Database > > Subject: Re: [sqlite] Problem with using WAL journal mode in embedded > > system (disk I/O error) > > > > On Mon, Sep 26, 2011 at 2:21 PM, Korey Calmettes > > <kcalmet...@icontime.com>wrote: > > > > > Thanks for responding so quickly. > > > > > > I performed the same general experiment. Here is the output when the > > > error occurred. > > > > > > sqlite> .tables > > > (5386) os_unix.c:28414: (22) mmap(//test.db-shm) - > > > > > > > Looks like a mmap() call is failing here: > > http://www.sqlite.org/src/artifact/10e0c4dcdb?ln=4009-4011 > > > > Looks like you are using a database in the root of the filesystem > > ("/test.db"). Do you get the same error if you put the database file in > > a directory someplace? > > > > > > > (5386) statement aborts at 109: [SELECT name FROM sqlite_master WHERE > > > type IN ('table','view') AND name NOT LIKE 'sqlite_%' UNION ALL SELECT > > > > > name FROM sqlite_temp_master WHERE type IN ('table','view') ORDER BY > > > 1] disk I/O error > > > Error: disk I/O error > > > sqlite> > > > > > > Any ideas? > > > > > > Korey > > > > > > > > > -----Original Message----- > > > From: sqlite-users-boun...@sqlite.org > > > [mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Richard Hipp > > > Sent: September 26, 2011 8:38 AM > > > To: General Discussion of SQLite Database > > > Subject: Re: [sqlite] Problem with using WAL journal mode in embedded > > > system (disk I/O error) > > > > > > On Mon, Sep 26, 2011 at 11:30 AM, Korey Calmettes > > > <kcalmet...@icontime.com>wrote: > > > > > > > ~ # sqlite3 test.db > > > > SQLite version 3.7.7.1 2011-06-28 17:39:05 Enter ".help" for > > > > instructions Enter SQL statements terminated with a ";" > > > > sqlite> .tables > > > > test > > > > sqlite> pragma journal_mode=wal; > > > > wal > > > > sqlite> .tables > > > > Error: disk I/O error > > > > sqlite> > > > > > > > > > > > > Any ideas on what may be causing this error and any suggestions for > > > > a work-around? > > > > > > > > > > Type: > > > > > > .log stdout > > > > > > at the beginning of this session and run your experiment again please. > > > The extra output might give some clues. > > > > > > > > > -- > > > D. Richard Hipp > > > d...@sqlite.org > > > _______________________________________________ > > > 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 > > > > > > > > > > > -- > > D. Richard Hipp > > d...@sqlite.org > > _______________________________________________ > > 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 > > > > > > -- > D. Richard Hipp > d...@sqlite.org > _______________________________________________ > 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 > -- D. Richard Hipp d...@sqlite.org _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
