Hello everybody, I know there are lots of documentation about sqlite and multithreading and yes, I have read all of it! ;) I'm to the point where I think about restructuring my application in order to make it more reactive, and I'd like to ask for your wise comments.
The scheme I would like to implement is as follow: - The main thread (which displays the GUI and must therefore not be frozen by some long query) is the only thread that does write accesses to the database. Writing remains very seldom and fast, though. - Around this thread, several other threads may exist that run read-only queries on demand by the main thread (typically, when the user wants to display something in the user interface. I need to use a different thread because I don't want to block the GUI while the request is running). When the request is finished, the result is displayed by the main thread. However, the main thread may also want to abort that request, for instance if the user decides to display something else by the meantime. The problem is that there may be several of these peripheral threads (I estimate up to 5), and they must all be interruptible individually. This is where my problem lies: sqlite has a function to interrupt queries (sqlite3_interrupt), but it stops all the queries of a given connection. Therefore, to ensure all queries are individually interruptible, I must open one sqlite connection per thread. By doing so, and considering that the main thread only writes seldomly, I think I would not experience any GUI is freeze, as all the lengthly queries would be executed by other threads that can be interrupted if the user decides to take some further action before they complete. The only freeze condition that I may have would be when the main thread wants to write to the database while other threads are still reading it. In that case, the GUI may freeze while the main thread tries to acquire its lock. However, I think I can easily workaround that using another thread that is only dedicated to writing and buffers write requests as they arrive. This design will require a major overhaul of my application, so I'd like to make sure it is a good idea. I'd like to avoid using multiple connections, but I feel like I have no choice there. Would anyone have something to say against that design or would suggest a better idea? Thanks, Alex. _______________________________________________ sqlite-users mailing list sqlite-users@sqlite.org http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
