> However, I am surprised that it does not at least possess a > list of all open handles to a given database. If I had that, then I could > close all DB connections either before the delete or after. Are you sure > that such a list does not exist?
If SQLite was able to obtain such list (not in the same process but among several different processes, remember?) that would be a serious security breach in the kernel. Let alone the possibility of closing file handles in other processes. > Wouldn't it use it for mechanisms like > 'unlock notify' and 'busy handler', etc? It's implemented using simple polling technique: try to lock; if it's unsuccessful sleep for some small time; try to lock again and repeat that until lock is successful or the total waiting time is too long. Pavel On Fri, Nov 12, 2010 at 11:44 AM, Dennis Suehr <den...@suehr.me.uk> wrote: > Simon, > > Many thanks for your prompt and thorough response. > > Just a couple of follow-up questions if I may: > > Firstly, a bit more background information. The system will be running on > Linux (kernel > 2.6.0) and all accesses to the database will be via local > disk (ext3 or similar). > > 1) I appreciate your explanation about any any open connections to the file > still being able to write to it until they close it. I suppose that 'fuser' > could be used to send a SIGTERM or similar to the processes holding open > file handles. I will have to give some additional thought to how I go about > this 'delete' operation. > > 2) Regarding, SQLite and open handles to a database, that is fair enough > that it does not have a mechanism send alerts to all processes connected to > a given DB. However, I am surprised that it does not at least possess a > list of all open handles to a given database. If I had that, then I could > close all DB connections either before the delete or after. Are you sure > that such a list does not exist? Wouldn't it use it for mechanisms like > 'unlock notify' and 'busy handler', etc? > > 3) Finally, am I correct in thinking that if I used 'pragma locking > exclusive' that I can lock the entire database even after closing my > connection? > > Cheers, > > Dennis > _______________________________________________ > sqlite-users mailing list > firstname.lastname@example.org > http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users > _______________________________________________ sqlite-users mailing list email@example.com http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users