Setting sqlite config SQLITE_CONFIG_SERIALIZED returns SQLITE_MISUSE on iOS 5

Question

With the release of iOS 5 we are getting more and more errors when setting the serialized option for the sqlite database (so its save to be used for multithreading). We are getting SQLITE_MISUSE error code on sqlite3_config. Has someone noticed this odd behavior? And does someone know how I can fix this? It works perfectly fine on previous iOS versions.

here is the code:

- (sqlite3 *)getNewDBConnection {
    NSLog(@"sqlite3 lib version: %s", sqlite3_libversion());

    //sqlite3_config() has to be called before any sqlite3_open calls.

    if (sqlite3_threadsafe() > 0) {
        int retCode = sqlite3_config(SQLITE_CONFIG_SERIALIZED);
        if (retCode == SQLITE_OK) {
            NSLog(@"Can now use sqlite on multiple threads, using the same connection");
        } else {
            NSLog(@"setting sqlite thread safe mode to serialized failed!!! return code: %d", retCode);
        }
    } else {
        NSLog(@"Your SQLite database is not compiled to be threadsafe.");
    }

    sqlite3 *newDBconnection;

    // Open the database
    if (sqlite3_open([[self getDatabaseFilePath] UTF8String], &newDBconnection) == SQLITE_OK) {
        NSLog(@"Database Successfully Opened :)");
    } else {
        sqlite3_close(newDBconnection);
        NSLog(@"Error in opening database :(");
    }

    return newDBconnection; 
}

and this is the output:

sqlite3 lib version: 3.7.7
setting sqlite thread safe mode to serialized failed!!! return code: 21
Database Successfully Opened :)

I'm experiencing the same issue, and calling sqlite3_initialize() after sqlite3_config() does not resolve the issue. The call to config() still returns SQLITE_MISUSE (code 21). Anyone was able to figure this out? — , Oct 28 '11 at 20:47

score 12 · Accepted Answer · edited Feb 16 '18 at 00:57

12

I struggled long and hard with this as well and finally got the solution.

As @enobufs said, sqlite3_config() needs to be called before sqlite3_initialize(). However, the OS might initialize SQLite for us so I also do a sqlite3_shutdown() before the sqlite3_config().

sqlite3_shutdown()
sqlite3_config()
sqlite3_initialize().

Then its also necessary to use the same connection for every query as it is the access to the database connection that gets serialized. As described here http://www.sqlite.org/capi3ref.html#sqliteconfigserialized

So I create a connection as soon as the app starts up and the pass that connection to every class that needs it.

edited Feb 16 '18 at 00:57

patridge

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answered Mar 22 '12 at 15:18

naudecruywagen

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thanks for the tipp. it seems to work now but this needs further testing if it really fixes our problem and it will not have any side effects. – Buju Apr 17 '12 at 18:14
@naudec at what point in the application do you call the 3 methods? is it in the `appdeleage.cs`? and what parameters do you pass into `sqlite3_config()` – JKennedy Nov 04 '19 at 15:38
Apologies @user1 I don't have access to this codebase anymore and it's too long ago for me to remember – naudecruywagen Nov 13 '19 at 07:36

score 1 · Answer 2 · edited Feb 16 '18 at 00:57

1

Is the sqlite3_config() called before sqlite3_initialize()? The function returns SQLITE_MISUSE if called after sqlite3_initialize() and before sqlite3_shutdown(). See http://www.sqlite.org/c3ref/config.html for more details.

edited Feb 16 '18 at 00:57

patridge

26,385
18
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answered Oct 17 '11 at 20:14

enobufs

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I'm not calling any of these methods. It works fine in previous versions. – Buju Oct 18 '11 at 08:17
1

I wasn't calling *_initialize()/*_shutdown() functions with earlier versions of ios either and working fine. But multithread operations failed with ios 5. Apparently, sqlite3_initialize() is called automatically if the library is compiled without SQLITE_OMIT_AUTOINIT. To resolve my problem with ios, I explicitly called sqlite3_initialize() after sqlite3_config() before any other sqlite3 function calls. Now my sqlite3_config() returns SQLITE_OK and multithreaded access working properly on ios 5. I agree something has changed with ios5. Good luck! – enobufs Oct 18 '11 at 22:34

Setting sqlite config SQLITE_CONFIG_SERIALIZED returns SQLITE_MISUSE on iOS 5

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