Dear all, I experience some performance issues with SQLite.
I have an application that uses SQLite to store user data, including agenda information. One of my client has a relatively big database (around 1.3Gb). I have indexed the database so that the queries take a reasonable time to execute. In the general case, the complete update process of the more demanding tasks (handling of user action, search in database and screen refresh) takes less than 1 second. But, at very sparse moments, for reasons I cannot identify, one of my clients experiences freezes in the application that can raise up to several minutes ! After those freezes, the application continues to work normally I instrumented my application to find the origin of the freeze. From this instrumentation, I can guarantee that the time is spent in the database request. But what is strange is that executing exactly the same request, with exactly the same parameters on exactly the same database content just after, or just before the problem occurs does not cause any performance issue. I logged all information on what was happening on my client database (I currently only have one client that encounters this strange behaviour), and the only strange thing that I collected from his computer is the following kind log from sqlite : 08-11-2015 (13h25): Exception: SQLiteDataBase : Error callback -> 27 : delayed 25ms for lock/sharing conflict at line 39428 08-11-2015 (13h25): Exception: SQLiteDataBase : Error callback -> 27 : delayed 75ms for lock/sharing conflict at line 39428 27 is the SQLIte error code, and the text located after is the sqlite message. The occurrence of such warnings do not seem to be direcly linked to my problem, as they can appear on database access that do not suffer from performance issues, and some database access with performance issues can appear without those strange logs. But, for me, those logs are strange because : - I never encountered them on other computers (even if it's true that I did not pay attention to those logs before this problem was reported by my client) - my application is supposed to be the only process to access the database, and only one thread of my application is accessing the database. So, does someone has an idea on what can cause such performance issues on some sqlite DB requests ? Thanks in advance, Brice PS: the problem is present at a client computer running a Windows 7 over a relatively old computer (intel core 2 duo) with 4G ram. The version of sqlite is the last one (because I upgraded hoping this would solve the issue), but was also observerd with an older version of sqlite.
