On 2 Jul 2014, at 12:02pm, Grzegorz Sikorski <g.sikor...@kelvatek.com> wrote:
> My code works fine up to about 1020 connections to the database. After around > this number, I get an error "unable to open database file". [snip] This should not happen. But I don't know why it would happen. I have seen individual apps make more than 5000 connections to SQLite databases (not concurrently, but closing one before opening another) without problems. Mind you, that was on a desktop computer, not under iOS. Please make sure you are checking the results returned by /all/ sqlite3_ calls, including _close(), and reporting all errors. Don't check just the results returned by operations which make changes to the database. But if everything returns SQLITE_OK then you shouldn't be having those problems. Please post more info, perhaps with the extended error code. > I am not sure if there is any reason why keeping opened connection in whole > application lifetime is really something I should do? I would prefer to open > database only when it is needed, to avoid risk of file corruption on power > loss. If your app uses one database during one 'run', and need frequent access to it, there is no need to keep closing and reopening your database. As long as you use transactions properly and do not disable proper journal handing, you will find that SQLite is rock solid and you do not need to keep closing a database to make sure it is updated. Under iOS you should, of course, close the database when your app quits. And you may also want to close it for the following notifications: applicationWillResignActive: applicationDidEnterBackground: and reopen it for applicationDidBecomeActive: applicationWillEnterForeground: It's possible that your app might want to do processing while in the background so you might not want to close in response to 'applicationDidEnterBackground:'. Alternatively instead of opening the database on 'start' and 'wake' you can keep track of its 'open' status in a boolean variable and check it before each database operation. This would allow an application to open a database connection only when needed, then keep it open until the next suspend, background, or quit. Simon. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
