Core data fails to open store: "Error validating url for store"

Question

I've been working on an app for quite a while and suddenly started to hit this error when the app tries to open a Core Data store. I hadn't made any changes to my data model or the data access code for over a month, so I don't think it can be anything that I'm doing wrong as far as interacting with Core Data. (Meaning, the URLs are ok, the call pattern is ok, etc...)

Interestingly, these are the log lines immediately before the error:

/SourceCache/GoogleMobileMaps/GoogleMobileMaps-217.2/googlenav/mac/TileStore.mm:209 unable to open /var/mobile/Library/Caches/MapTiles/MapTiles.sqlitedb: (14) unable to open database file /SourceCache/GoogleMobileMaps/GoogleMobileMaps-217.2/googlenav/mac/TileStore.mm:155 file doesn't exist /var/mobile/Library/Caches/MapTiles/MapTiles.sqlitedb: (2) /SourceCache/GoogleMobileMaps/GoogleMobileMaps-217.2/googlenav/mac/TileStore.mm:209 unable to open /var/mobile/Library/Caches/MapTiles/MapTiles.sqlitedb: (14) unable to open database file /SourceCache/GoogleMobileMaps/GoogleMobileMaps-217.2/googlenav/mac/TileStore.mm:235 unable to open /var/mobile/Library/Caches/MapTiles/MapTiles.sqlitedb: tile data will not be cached

So it looks like there is "something" wrong with the sqlite layer in general. Has anybody seen this before? Is there a recovery option besides wiping my device? It's currently running 3.1.3 and I'd really hate to upgrade to 4 because it's currently my only way to test that the app will run for people who haven't upgraded.

One thing I did notice: shortly after I first hit this error, I wanted to see if any other apps were having problems. Sure enough, the iPod app had forgotten everything about me, but it was able to recover after syncing. So maybe there is some recovery mode? (Although, even if I can recover for my app, the Maps APIs might burn a lot of bandwidth if they can't cache the map tiles...)

Ryan

Answer 1

For what it's worth, I found the culprit and it has nothing to do with Core Data, sqlite, or the file system. The app uses a lot of small audio clips and I was pre-caching them all as AVAudioPlayers. I knew this was probably a bad idea, but it was quick and easy so I figured I'd keep doing it that way until I hit some kind of problem. (I'd put a wrapper around the players so that I could delay instantiation if required without affecting the rest of the system, which is what I'm doing now.) I just assumed the problem would show up as an audio player problem and not somewhere else seemingly totally unrelated.

I realized there must be a code error when I found the simulator also misbehaving, but in a different totally inexplicable way (keyed archives weren't being written properly). When I backed out of the most recent change I'd made (adding a new batch of audio clips), the problems vanished.

Hopefully this helps someone in the future!