ok, I'll wait for the walk around. I always use a BEGIN; COMMIT; transaction but often, after a COMMIT; the -wal file does not change in size, it seams it's not checkponted. Anyway do you think that with WAL journal mode I should continue to use BEGIN; COMMIT; statement? or not?
Il 02/09/2010 14.43, Richard Hipp ha scritto: > On Thu, Sep 2, 2010 at 8:34 AM, Michele Pradella<michele.prade...@selea.com >> wrote: >> Hi, >> I found a strange behavior of the sqlite 3.7.2 with WAL journal mode. >> Yesterday I found my application DB with a -wal file of 1,5GB and a -shm >> file of few MB (about 9MB) with a DB file of 1,2GB: in this >> situation I got the process memory wasted by "mapped file" of the -shm >> file. It seams that the file is mapped a lot of times in memory so the >> process memory become 2GB and it can't allocate more memory. In that >> situation operation made on the DB cause I/O disk errors probably due to >> the wasted memory. >> > By coincidence, the SQLite developers were just discussing this problem > earlier this morning. There are technical issues with windows that make a > solution difficult. We are trying to come up with a work-around. (The > problem you describe is specific to the windows backend and does not come up > in unix.) > > >> I'm doing some other test to reproduce the problem, but I think that >> could be when I got a lot of operation between a BEGIN; COMMIT; >> So is it ok to use the BEGIN; COMMIT; with the WAL journal activated? >> is there some kind of limit in the number of operation between a BEGIN; >> COMMIT; statement? >> > SQLite will not checkpoint the journal until you commit your transaction. > So if you leave the transaction open too long, the WAL file and the -shm > file will grow excessively large. WAL works best with many smaller > transactions. If you have one or two big transactions, then using a > traditional rollback-journal mode works better. > > > >> I try to use the PRAGMA wal_checkpoint; to try resolve this situation, >> but seams that command was ignored by sqlite because the -wal file does >> not change in size, even the DB file. >> _______________________________________________ >> sqlite-users mailing list >> sqlite-users@sqlite.org >> http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users >> > > -- Selea s.r.l. Michele Pradella R&D SELEA s.r.l. Via Aldo Moro 69 Italy - 46019 Cicognara (MN) Tel +39 0375 889091 Fax +39 0375 889080 *michele.prade...@selea.com* <mailto:michele.prade...@selea.com> *http://www.selea.com* _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
