You should synchronize your backup (copy). Try surrounding it with an exclusive transaction.
Stan Bielski wrote: > Sorry for the repost, but the original thread was hijacked by another > list user. This is a serious problem IMHO; it looks like the DB can't > be backed-up without rendering the machine unusable if a query hits it > while a copy is in progress. > > Hello, > > In the course of copying a largish (20 GB) database file while > accessing it via sqlite3, the machine became very unresponsive. I > opened task manager and found that the system was using a huge amount > of virtual memory, causing it to thrash. Per-process memory usage > looked normal and did not add up to anywhere near system-wide VM > usage. > > I ran into this issue at a customer site and was able to reproduce it > using a local Windows 2008 installation. I have not installed any > backup software or a virus scanner. Storage is local disk, SQLite > version is 3.3.17. > > At first I thought that this was a general Windows problem involving a > process accessing a file that is being copied, but other binaries I > tested do not cause the same behavior that sqlite3 does. I performed > the following experiments to try to diagnose the issue. > > Case 1: > > * I copy a 20 GB sqlite DB using Windows' own copy utility (e.g. via > explorer). > * At any point during the copy, I open the file being copied in sqlite3 > * I exit sqlite3. > * During the rest of the copy the OS will consume virtual memory > linear (seemingly identical) to the amount of data copied since the > process opened the file. > > I repeated this experiment using a similarly-sized file created from > /dev/zero (i.e. an invalid DB) and the results were the same. > > Case 2: > > * I copy the sqlite DB using Windows' own copy utility (e.g. via explorer). > * At any point during the copy, I run 'strings' with the file as an argument. > * I exit strings. > * The copy does not result in the OS consuming additional virtual memory. > > Case 3: > > * I open the DB in sqlite3 > * I let sqlite3 idle and do not input any commands. > * I copy a sqlite DB using Windows' own copy utility (e.g. via explorer). > * I continue to let sqlite3 idle and do not input any commands. > * During the rest of the copy the OS will consume virtual memory > linear (seemingly identical) to the amount of data copied since the > process opened the file. > > Is there a workaround for this issue? Any assistance or info is appreciated. > > Thanks, > -Stan > _______________________________________________ > 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
