Hello everybody, I'm hoping someone might have some insights on a particular issue I've been running into. Here some details:
I'm working on a multi-platform app that uses a cross-platform library with SQLite 3.7.16.1 built into it (i.e. not using the built-in SQLite version in Android or other platforms). We make (re)use of prepared statements for INSERT and UPDATE on the database, and we use FULLMUTEX serialized threading mode. We use explicit transactions for some bulk INSERT operations, but most other calls use implicit transactions. Everything worked fine until I switched journal_mode from MEMORY to WAL. Now when I run the app I started seeing SQLite errors pop up, the first error is sqlite3_step failed: unable to open database file (error code: 14) and after that I get a lot of follow-up errors from my prepared statements such as sqlite3_bind_text failed: library routine called out of sequence (error code: 21) This does not happen on iOS or other platforms using the same cross-platform library, leading me to believe this might be an Android specific issue, maybe due to VFS differences or something like that. There are multiple threads in the same process accessing the database, all using the same shared connection. My understanding is that due to the FULLMUTEX mode SQLite is serializing all these calls. Now WAL basically reenables concurrent reads and writes, my suspicion is that the error is caused by trying to do concurrent writes even though it shouldn't. However, in that case I would expect to see a database locked error instead of this weird unable to open database file issue. Does any of this sound familiar to anyone? I wasn't able to fix it by any means other than setting journal_mode back, actually all other journaling modes work fine except WAL. I looked around and couldn't really find much on people having issues with WAL on Android, so it might be something about the combination of WAL with prepared statements and FULLMUTEX? Any help is appreciated! // Sascha _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
